Indoor Missile Ballistics

I wrote a bit about missile ballistics previously. Part of that discussion is predicated on the observations that (a) the move and range statistics given in Chainmail show signs of excellent research, and are very historically accurate, but (b) the transition in OD&D from outdoors-to-indoor via a simple yards-to-feet conversion (and no time scale conversion at all) was pretty much not thought out at all. Here's a bit more on that.

If we take the original Chainmail maximum ranges for missiles as a starting point (assuming base level of historical accuracy), in each case we can use some ballistics calculations to back-calculate the launch speed of the missile in question. Then we can use that value to calculate the indoor range of the missile, under different ceiling heights. Consider the following results:


Tools and Assumptions

• I used the "Ballistic Trajectory Calculator" by Stephen R. Schmitt to compute outdoor launch speeds, the greatest possible angle for a given ceiling height, and the resulting maximum ranges.
  
• Maximum outdoor range is automatically given by a 45-degree shot, but with a limited ceiling overhead the maximum possible launch angle (to avoid hitting the ceiling) is usually between 5 and 20 degrees or so.
• Distances have been crudely converted using a simple 1 meter = 1 yard = 3 feet assumption. Resulting ranges in inches have been rounded to the nearest multiple of 3, the same as in classic D&D.
• We presume Earth-like gravity (9.8 m/sec^2) and an initial launch height of about a normal man's shoulder (1.5m).
• The "Thrown" category includes spears, hand axes, daggers, etc. The "Crossbow" has the same range parameters as a Composite Bow.
  

Results and Analysis

Obviously, the range of the maximum possible shot indoors is dependent on the ceiling height; a higher ceiling allows for a longer potential shot. Also, the effect on different missiles is not linear; that is, the more powerful weapons suffer more than the lighter weapons. The overall effect is to "bunch up" the ranges of the weapons closer together, minimizing differences.

An interesting data point to look at is under the 10' ceiling, played with the "old school" game scale of 1"=10'. It turns out that the Shortbow has exactly the same game range as we started with; it's 15" in both Chainmail and our ballistics-accurate indoor conversion. However, Thrown weapons are not as hamstrung by the low ceiling, and in fact their in-game range has doubled to 6". Meanwhile, a weapon like the Heavy Crossbow is relatively more disadvantaged, with a resulting game range of 18" (a quarter less than its Chainmail range of 24").

Note that Thrown weapons outdoors actually have a maximum-shot height of only 8.8 meters (27 feet) -- so as soon as the indoor ceiling height reaches something above 20 feet, they can effectively achieve the maximum-possible shot range of 90 feet (30 yards/meters), the same as outdoors.

Suggestions and Options

What to do with this? Here are several different options for using this in your D&D game:

1. One option is to use the tables above directly in your game for indoor missile fire. That may be overly complicated, however, and unnecessary: ranged combat will usually be much more limited by room size or extent of lighting.
2. If you actually game at an "old school" scale of 1"=10 feet, then you can use the standard Chainmail ranges in inches and you'll be pretty close to the physically realistic results above (however, see below).
   
3. Assuming a "new school" game scale of 1"= 5 feet, you might take the classic game ranges for bows and just double them (giving max ranges like 30/36/42/48 inches); thrown weapons quadruple (to 12"). This is pretty close to the ranges shown above for a 10' ceiling, but it's still pretty complicated, and is overly generous to the more powerful weapon types.
4. We might approximate the different bows as being practically of equal range in a typical 10' high corridor or room. For example, stipulate that every type of bow has a 30" range indoors (150 ft); again, thrown weapons travel 12" (60 feet). That's probably close enough to our improved-accuracy model.
   
5. Or, you might choose to basically dodge the whole issue, saying that additional obstruction issues reduce ranges back to the Chainmail givens of 15/18/21/24 inches (again, thinking 1"=5 feet here); lighting will probably always be less than that anyway, and we thereby keep the same balance with other movement/spell/special abilities in the game. Nevertheless, I'd strongly recommend increasing the thrown weapons range to either 6" or 12", depending on your taste in the matter.
6. Whichever option you pick above, it's pretty easy to account for different ceiling heights (if you want to). Take a 10' ceiling as your base. For a 20' ceiling add +50% to the chosen ranges. For a 40' ceiling, double the listed ranges. Regardless, thrown weapons can't ever travel more than 90 feet (the maximum outdoor range, effectively achieved with a 20 foot ceiling).
   

At the moment, for simplicity I'm going with suggestion #5 above (range in inches as in classic Chainmail, except for thrown weapons which can be hurled 12" indoors, i.e., 60 feet). If anyone uses a more sophisticated option, I'd be delighted to hear how it works out.

Wandering Monster Summary

So, I actually spent, like, the last 5 blog posts or so considering issues springing out of OD&D's Underworld Wandering Monster tables (Vol-3, p. 10-11), considering these as a presentation of a "basic" D&D monster ecology, and a comprehensive presentation of all the most common hostile monsters in the game. Here's some final thoughts:

First, it's pretty freaking cool. The different levels of OD&D monsters are fairly well balanced in both overall power (Hit Dice) and nicely scaling up the perceived frequency of exotic special abilities (poison, paralysis, spells, etc.) They're mostly all recognizable to the new or casual player, leaving crazy "wahoo" new monsters for later editions (and by necessity, special hand-placement by the DM); I think that's a good thing.

Secondly, it's specialized for one particular game campaign/setting (Castle Greyhawk, with its idiosyncratic Giant Hogs, Weasels, White Apes, Thouls, etc.), and you really should customize these tables if you use them elsewhere. The tables are so short and simple that it's really super-easy to do this customization. In comparison, I think the attempt in AD&D to create more expansive tables incorporating every one of a much larger encyclopedia of possible creatures is really a failed experiment. (Other examples of AD&D's frustrating project to generalize and disconnect rules from any specific setting/referent: Disease, Outdoor Movement.)

Finally, speaking as one of the rare gamers who received a copy of the old blue Basic D&D set tabula rasa (i.e., no contact with any older gaming community, always the initial point of contact for the game in my neighborhood using the official written text only), it's something of a shame that the original 1974 edition, with all of its intimacy and call to customization, underwent an effective "cover up" by TSR in the AD&D period. Literally not knowing what it was for many years, it's now definitely my favorite and most immediate version of the game.

Missing Monsters

So here's a bit about the monsters that appear in the OD&D Wandering Monster lists, but don't actually have explicit statistics given in those rules. A rundown by category, from most common to least:

Giant Animals. We're all familiar with these. Things listed as "Giant X" where X is some normal animal type include: Rats, Hogs, Ants, Snakes, Weasels, Beetles, and Scorpions. Most of these are in monster levels 3 or 4 (although Giant Rats are level 1). All of these have some analogous entry in the AD&D Monster Manual, so post-1977 you could use that resource to fill things in (recognizing that some monsters got boosted in the OD&D --> AD&D switch; see the last post). But what would the DM do running with just OD&D itself? Some guidelines in Vol-2:

LARGE INSECTS OR ANIMALS: This category includes giant ants and prehistoric monsters. Armor Class can be anything from 8 to 2. Hit Dice should range from 2 to anywhere near 20, let us say, for a Tyrannasaurus Rex. Also included in this group are the optionally usable "Martian" animals such as Apts, Banths, Thoats, etc. If the referee is not personally familiar with the various monsters included in this category the participants of the campaign can be polled to decide all characteristics. Damage caused by hits should range between 2-4 dice (2-24 points). [OD&D Vol-2, p. 20]

A few comments here: Taken literally, the rule in the text above (min 2HD) would make for really heavyweight Giant Rats, which are of course level 1 and given only 1/2 hit die in AD&D. Note also that the damage parameters are rather terrifying -- in OD&D, 2 dice is the same as a Hill Giant, while 3-4 dice is the same as a double- or triple-size Purple Worm (i.e., Sea Monster). Personally, looking at the Wandering Monster charts, my first guess would have been to assign a number of Hit Dice according to whatever monster level is indicated -- and you'd be accurate to the AD&D Hit Dice (or one less) in each case.

Normal Animals. Oddly, there are a few animals pointedly listed without the "Giant" identifier. These are: Centipedes, Spiders (level 1 each), and Lizards (level 2). What to make of these? Obviously, in AD&D they're each listed as a Giant type with attacks like weak poison, but there's no indication of that in OD&D. They seem to be referenced in this entry from the monsters book:

INSECTS OR SMALL ANIMALS: These can be any of a huge variety of creatures such as wolves, centipedes, snakes and spiders. Any hit will kill the smaller, while larger beasts (such as wolves) will receive one Hit Die. Generally speaking they will be Armor Class 8. [OD&D Vol-2, p. 20]

So perhaps at one point the Centipedes and Spiders listed in OD&D effectively had just 1hp? Were we meant to intuit a poison attack, if anything? It's hard to tell here. (One other thing that I point out elsewhere is how ridiculously huge the 3HD Giant Lizard is in AD&D -- pretty much like every monster given a specific size in feet there -- 15' long, whereas all other monsters in OD&D from levels 1-4 are basically human-scaled.)

Thouls. So, Thouls are listed in the OD&D monster level 2 chart, but they were never given statistics in any OD&D or AD&D publication. Looking only there, I might think to give them 2HD (by level) and some abilities like Ghouls (of whom they seem cognate, and they come immediately prior to in the encounter table). Of course, Moldvay Basic D&D later gave them 3HD, paralysis, regeneration like a troll, and the appearance of a hobgoblin. Perhaps more interestingly, we have evidence that the original Greyhawk Castle notes show the monster with 4HD and similar abilities -- which would make it distressingly powerful compared to other creatures on the level 2 list. (This information from Gygax, via Gene Weigel, via T. Foster over at the Dragonsfoot boards.)

White Apes. These occur in the level 4 listing. Granted all the "John Carter from Mars" references, it's pretty obvious that these refer to the White Apes of Barsoom, who appear alongside such types as Apts, Banths, etc. (mentioned in the first quote above). These are huge, 4-armed, semi-intelligent gorillas lacking any direct statistics in D&D. I assume that AD&D's "Ape, Carnivorous" (5HD) is the replacement here, although it only has standard limbs. 3E D&D has the "Girallon" monster which is quite obviously the White Ape under different trade dress (7HD, huge, white-furred, and 4-armed; stats here and picture here).

Other Considerations. The preceding account for all of the OD&D Wandering Monsters that lack statistics in that game. Here's a few other thoughts:

Let's say you think to replace the missing monster stats with stuff from the AD&D Monster Manual. You've got to be careful for a few reasons. First, note that some animals may not have been intended as "giant", but that's all you have available in the MM. Second (and related), note that some amount of Hit Die inflation occurred between OD&D and AD&D, and that might be true for the missing monsters as they appear in the MM. Third, you've got to make some decisions about exactly which AD&D monster of several sub-types should fill the slot (my suggestions, generally looking for appropriate Hit Dice and size: Spiders-->Large Spiders, Lizards-->Giant Lizard, Giant Hogs-->Wild Boar, Giant Beetles-->Boring Beetles, Giant Snakes-->Poisonous or Constrictor Snakes?) Fourth, and again related, some of these types will skew more dangerous than others on the same list (e.g., poisonous large spiders HD1+1 at level 1, giant lizards HD3+1 at level 2). In particular, using either of AD&D's Poisonous or Constrictor Giant Snakes at level 3 is really dangerous (respectively HD 4+2 or 6+1 by special attacks each; compare to Ogres listed at level 4 without any instant-death ability) -- I recommend a 3HD Constrictor type at that level.

One final peculiarity is that, for some reason, most of these types have damage entries listed in Sup-I Greyhawk, but are still missing the more basic stats (AC, MV, HD, etc.) To see this, remember that throughout OD&D, basic monster stats were in a separate table/location from attacks and damage (those being introduced in Sup-I -- and really this whole issue is what made the Monster Manual product so highly desirable and the first publication in the AD&D line). So if you look at the new, large Sup-I attacks/damage table, although they're all strung one-after-the-other in a single unified listing, you see three identifiable sections: 1st, all the original monsters from Vol-2 (Sup-I p. 16-18); 2nd, "missing monsters" of the type we discuss here (midway down p. 18); and 3rd, all the monsters being introduced elsewhere in Sup-I (p. 18-19).

Just looking for a moment at these orphaned damage entries, we see these types -- Giant (Sumatran) Rat, Wolf, Dire Wolf, Lion, Sabre-tooth Tiger, Giant Weasel, Mastodon, Giant Spider, Giant Lizard, Giant Toad, Giant Snake, Giant Crab, Giant Beetle, Giant Scorpion, Crocodile, Tyrannosaurus Rex. Note that the spider and lizard are now explicitly "Giant". While many of these damage stats match what you see in the Monster Manual, that's not the case for any of the monsters with multiple sub-types in AD&D, so you can't use that to synchronize them (e.g., snakes, spiders, beetles). For example, the entry for the Giant Snake indicates Attacks: 1 bite/1 constriction, Damage: 1-6 bite (poison noted), and 2-8/turn of constricting; now, if I allege above that the poisonous or constrictor snakes from AD&D are particularly scary, imagine an OD&D snake of the same hit dice that's both poisonous AND constricting. Holy smoke! (Recommend bumping that to a higher monster level if you use it.)

But irrespective of these Sup-I damage listings, there are still no basic stats anywhere in OD&D for our "missing monsters". Were they originally intended to be in Sup-I Greyhawk and got edited out at some point? Interesting to think about.

Hit Dice Inflation

Did you know that, in the switch from OD&D to AD&D, all undead were given a 1-hit-die addition (excepting ghouls)?

Most other monsters were, no surprise, simply copy-and-pasted into the Monster Manual -- sometimes with minor hit-point adjustments. Other monsters that got a hit-die boost were the Draft Horse (from 2 to 3), the Ochre Jelly (5 to 6), and the Medusa (4 to 6). Rocs went from 6 to 18, but even in OD&D the 6HD figure was noted as being for a "small variety", and subject to being "doubled or even trebled". The Pegasus went from 2 to 4HD, thereby flip-flopping the old Pegasus-Hippogriff rivalry (the latter keeping its 3HD in both editions).

Oddly, the Balrog (i.e., Type VI Demon) managed to go down in Hit Dice, from 10 to 8, and here's why: Earliest printings of OD&D included the Balrog at 10 Hit Dice (exceeded only by the biggest giants, dragons, and hydras/worms in the game), later redacted for intellectual-property issues. They later re-appeared as the Type VI Demon in Sup-III Eldritch Wizardry -- here with the novel listing of 8 hit dice footnoted as being 10-sided, i.e., the same basic expectation for hit points as the earlier 10d8 (as of Sup-II). Then in the switch from OD&D to AD&D, this footnote was stripped out, leaving them with the fairly meager 8 Hit Dice that you see in the Monster Manual.

(Personally, I have to condemn this kind of overly-clever fiddliness in Sup-III as being a totally unnecessary complication, poorly thought out in its implications such as for saves and to-hit scores, a symmetry-breaking anomaly in the core mechanics of the game, and precisely the kind of weak link that causes glitches in the AD&D version of the Balrog-based demon that we see here.)

Obviously, every edition has various inflations built into different parts of the product: for an analysis of changes from AD&D to 3E D&D, see here.

Wandering Monster Numbers

After you've generated a specific wandering monster type via OD&D Vol-3 (p. 10-11), now you've got to determine the number of these monsters. Unfortunately, OD&D pretty scrupulously refuses to set any specific number for monsters found in the dungeon.

Number of Wandering Monsters Appearing: If the level beneath the surface roughly corresponds with the level of the monster then the number of monsters will be based on a single creature, modified by type (that is Orcs and the like will be in groups) and the number of adventurers in the party. A party of from 1-3 would draw the basic number of monsters, 4-6 would bring about twice as many, and so on. The referee is advised to exercise his discretion in regard to exact determinations, for the number of variables is too great to make a hard and fast rule... [Vol-3, p. 11-12]

I've posed this question before and got some good feedback. Probably the best suggestion was "if in doubt, roll 1d6". Let's expand on that just a bit.

The quote above makes a distinction for a "type... [that] will be in groups" -- I guess that would be the humanoid types in Vol-2 that potentially come in the hundreds in the wilderness? Anyway, I'm not sure the distinction makes sense. Let's say at level 1 you generate Skeletons or Spiders or Giant Rats or something. Would you really want this to be "based on a single creature", i.e., you just encounter Skeletons or Spiders or Rats one at a time? That seems quite seriously deflating.

Personally, I don't see any reason why you wouldn't also want to see these non-humanoids in a group (such as 1d6 in size), both generally for interest, and also for game-balance sake (an intent which is implied in several places in OD&D). These other level 1 creatures are not more powerful than Orcs; since they're all about equal danger level, you'd think they should appear in approximately the same group sizes. Extrapolate this further -- while 1 Ogre makes intuitive sense on level 1, once you're on level 4 I wouldn't expect to see solo Ogres by default, I'd expect to see a whole bunch of them (possibly "a street of masses of ogres", as on Greyhawk's 7th level).

Obviously, my intuition was not used in later editions, which did explicate numbers appearing in later Wandering Monster charts, and show the Gygaxian naturalistic inclination of big groups of humanoids (7-12 orcs, 6-15 goblins in DMG) and much smaller collections of other types (1-4 fire beetles, 1-4 skeletons) -- even though the latter are clearly weaker encounters overall. I think that's a mistake; but fortunately OD&D directly advises that the DM "exercise his discretion" on this point, so we have a lot more freedom here.

So let's keep it simple -- Make the "basic number" for monsters just 1d6 in all cases (excepting creatures listed in the singular). Modify this by level as follows: Multiply/divide by 2 cumulatively for each level that the dungeon exceeds/undervalues the monster level.

This is what I've started using recently, and it seems to work well in the tests that I've run. It sort of follows the 3E observation that a x2 increase in number is worth a +2 increase in challenge rating (borne out as pretty accurate when I tested it) -- although in OD&D the levels are more compressed (only 6 categories, e.g., one monster level spans two character levels of fighters/wizards), so it's looking to me like x2 numbers per +1 monster/dungeon level is most fitting. (As a side note, I'm also awarding XP on the same basis, starting at 50XP for a level 1 monster, 100XP for level 2, etc.)

The playtests that I've been doing with a slightly modified OD&D Monster Level Matrix and Wandering Monster Tables seem to work very well -- dangerous but conceivably survivable with a bit of luck for PCs of an appropriate level. In summary I currently recommend:

• Basic 1d6 of any monster per encounter (exceptions: Ochre Jelly, Hydra).
  
• Multiply or divide by 2 for each level the dungeon differs from the monster, i.e.:

1. Multiply/divide by 2.
2. Multiply/divide by 4.
3. Multiply/divide by 8.
4. Multiply/divide by 16
5. Multiply/divide by 32.

For deeper dungeon levels, roll the indicated multiple of dice and add. For lesser dungeon levels, roll one die and divide by the indicated number, rounding up on a fraction of 0.5 or more (minimum 1 monster).

Wandering Monster Tables

Today we'll look at the Wandering Monster tables ("Monster Level Tables") in OD&D Vol-3, p. 10-11. I won't recreate all of the tables here; I'll just present some summary analysis and comments.

These tables come in Monster Levels 1 to 6 (like most things in OD&D), and you'll be consulting some random one based on a roll on the Monster Level Matrix before it (see previous post). The 1st-level table has 8 monsters, levels 2-4 have 10 monsters each, and levels 5-6 have 12 monsters each. (Compare to the OD&D spell lists which also have increasing numbers of entries at the higher levels.) The specific monster you get is determined by a simple roll of the equivalent die (i.e., a uniform probability distribution and a one-to-one correspondence).

Now, analysis is somewhat complicated because many of the lower-level monsters (mostly giant varieties of normal insects and animals) are not given specific statistics in OD&D. You get some very general guidelines in Vol-2, p. 20, but basically the individual DM has to intuit appropriate stats. I'll write more about this in a later post -- but for now let's agree to fill in the missing stats from the AD&D Monster Manual and use that as an approximation.

Here's a summary of the Hit Dice at each level (after discarding a small number of outliers). Analysis follows:

1. Range: Up to 1+1. Average: 1.
2. Range: 1+1 to 2+1. Average: 2.
3. Range: 3 to 5+1. Average: 4.
4. Range: 4 to 6. Average: 5.
5. Range: 4 to 8+2. Average: 6.
6. Range: 5 to 12. Average: 9.

Monster levels are based directly on Hit Dice. It's pretty easy to see that monster levels are based simply on Hit Dice. 1 HD creatures are all in the 1st level chart. 2 HD creatures are all at 2nd level, all 3 HD creatures at the 3rd level, etc. At higher levels, you get a wider range, but the bounds are always increasing (or at least, nondecreasing). On the one hand, there's no provision for a low-HD but powerful-special-ability monster to get bumped up to a higher level (that would be a development for later editions of the game), but at the same time, OD&D special abilities are more-or-less scaled to the Hit Dice of the monster anyway.

NPC classes are also based on Hit Dice. A number of entries specify NPC class types, and their positioning is again dictated purely by OD&D-style Hit Dice (always d6-based). For example, consider the magic-users: the 2nd-level chart includes Conjurers and Theurgists (HD 2 and 2+1 in Vol-1); the 3rd-level chart includes Thaumaturgists and Magicians (HD 3 and 3+1); and so on and so forth. This is one case where the danger level of magic-users is probably underestimated by looking solely at Hit Dice. (Note also that different levels of a given class generate multiple entries in the charts, so, lots of NPC entries; I think I'd prefer if these were merged to a single entry in each table, i.e., more room for non-human types.)

Clerics are largely missing. Guess what? Whereas there are entries for almost every level of fighter or magic-user from 1-9 or so, clerics are uniquely missing from the majority of the tables. In fact, they only appear in two places: Evil Priests at level 4 (cleric level 3, HD 3), and Evil High Priests at level 6 (cleric level 8, HD 7). I'd argue that this is yet another example of the game resisting a full commitment to integrating Catholic-style clerics into the milieu, partly due to the clash in thematics that they represent.

Inclusion if and only if the monster is hostile. Look at the OD&D Monster Reference Table, which spans two pages at the beginning of Vol-2 (pages 3-4). The first page (p. 3) covers all the basically hostile-to-men, dungeon-dwelling monster types (humanoids, undead, and classical chimera-types), and everything on this page is included in the OD&D Wandering Monster charts. The second page (p. 4) covers all the benign-to-men and/or fey/enchanted-woods-types, and almost nothing on this page is included in the dungeon Wandering Monster charts (with two exceptions: Minotaurs and the Ochre Jelly). Later D&D products include entries such as for dwarves and elves in the dungeon wandering monsters, but they do not appear here for OD&D -- and I personally find this to be highly laudable. Consider how this neatly implies the "always attack by default" rule for the OD&D Reaction Table (discussed previously here).

Frequency of special abilities increase with level. While it appears that monster level determination is based largely on Hit Dice (see above), the tables also have the very satisfying quality that the prevalence of monsters with powerful special abilities increases monotonically by level. If we count up monsters with major special abilities (such as poison, paralysis, regeneration, hit only by silver or magic, spell-casting etc.) we obtain this:

1. 2/8 = 25%
2. 4/10 = 40%
3. 6/10 = 60%
4. 6/10 = 60%
5. 8/12 = 67%
6. 9/12 = 75%

(I suppose if I gave full reign to my tiny bit of number-OCD, I'd want to see that statistic at the 3rd level be 50%; perhaps by making the snakes there non-poisonous, or something. A longer rant on those snakes in particular awaits for the later post.)

Idiosycratic animal inclusions. The insect/animal types included on these tables (mostly missing stats as noted above) are not exactly what I would think to initially associate with D&D. First of all, while most are noted as "Giant" types (rats at level 1; hogs, ants, snakes, weasels, beetles, and scorpions at levels 3-4), several are not. At levels 1-2 you've got Centipedes, Spiders, and Lizards listed without that identifier. While later AD&D shows Giant versions of each of these, it's unclear exactly what's meant in OD&D; poison is not suggested for them in the LBBs, and Vol-2 suggests "any hit will kill the smaller" in its guidelines for types like these (p. 20). Secondly, the common inclusion of above-ground mammals like Weasels and Hogs (not even boars at this point) on deep-level dungeon charts really rubs me the wrong way -- noting, of course, that among the many levels of Greyhawk Castle, "The sixth was a repeating maze with dozens of wild hogs (3 dice) in inconvenient spots, naturally backed up by appropriate numbers of Wereboars." (Gygax writing in Europa Magazine #6-8, April 1975 -- thanks to Allan Grohe for documenting that here, 1st paragraph).

Mostly missing the clean-up crew. As noted above, the Ochre Jelly appears at level 3 (uniquely, but for the Hydra, listed in the singular), yet none of the other "clean-up crew" amoeba/slime types do. This is particularly odd because elsewhere it's implied that these types should be found only as wandering monsters. ("Note that Ochre Jellies, Black Puddings, Green Slime, etc., are generally distributed randomly, usually in passages, without treasure."; Vol-3 p. 7).

Outliers. I mentioned above that for Hit Dice analysis purposes, I discarded a small number of outliers, so I should detail what they are. At the 2nd level you've got Thouls, which are entirely missing from OD&D and AD&D (more in a future post). You also have Lizards at the 2nd level; if this is the same as AD&D's Giant Lizards, then they have higher Hit Dice than anything else at that level (HD 3+1), and they're also the only huge-sized creature until levels 5-6 (15' long; noting that I think the size listings introduced for AD&D are generally over-inflated, and could be cut in half). At level 4, those troublesome Evil Priests have significantly lower hit dice than anything else (3), and at a level 6 the Purple Worms have much higher dice (15), so each of these I've precluded from the Hit Dice statistics above.

Conclusions. In general, I think the OD&D wandering monster tables are highly praiseworthy in being meaty, well-themed for D&D, highly playable, and sufficiently limited in scope as to be easy to use and highly manageable and comprehensible. They present mostly mythic, recognizable-to-the-layman creatures. There are just enough monsters present to believe that they could possibly all exist in some particular megadungeon somewhere (i.e., Greyhawk). They compare favorably to later iterations such as the AD&D DMG tables which are overly large and fiddly, reduce interesting creatures like Skeletons and Zombies to near-absence in favor of a truckload of rats/beetles/shriekers, and are subject to the complaint that they don't make any sense as a presentation of a particular dungeon ecology. In the few OD&D cases where some particular entry presents a monster that is missing, duplicated, undesirable, or overly idiosyncratic, then it's a trivial operation to use the slot for something more common in your own personal dungeon or campaign (notably Thieves, for example).

I really like the simplicity of these tables for the most common basic D&D monsters, and I wouldn't think that anything more complicated is really desirable (e.g., see AD&D DMG, FF, or MM2). If monsters more rare than those on these lists require hand-placement by the DM, then I think that's a good thing, as well.

Wandering Monster Levels

This is the first in a series of posts on the math behind the presumed dungeon-monster ecology in OD&D. Specifically, we'll be looking at the various Wandering Monster tables and figures presented in OD&D Vol-3, p. 10-11. Interestingly, there's significant evidence that these tables came out of particular Greyhawk Castle play (thereby being representative of that specific setting), whereas later publications moved in a direction of greater generality.

In each edition of D&D, there have been tables for Wandering Monsters, and they're often dual-purposed for such things as random dungeon stocking, etc. Before these tables are accessed, there is something like a "Monster Level Matrix", which I'll look at here; consider the versions in Holmes, OD&D, and AD&D (in order of increasing complexity):


Now, what I've done here is not directly transcribe the tables themselves, but rather convert them to frequency statistics (i.e., showing which possibilities are most likely; OD&D rolls 1d6, Holmes 1d12, and AD&D 1d20).

Holmes has about what you would expect. In each dungeon level, the equivalent level of monster is most common; the others are sequentially less likely, or, at 2nd level, they're equally split between small numbers of 1st & 3rd-level monsters. Simple.

Now look at the Original D&D tables. They're tough, man. At 1st level, the possibilities are even between 1st & 2nd level monsters. On the 2nd dungeon level, the most likely encounter is already 3rd-level monsters! (For example: Wights, ochre jelly, giant snakes, 4th-5th level fighters, 5th-6th level magic-users.) By the 3rd dungeon level, 4th-level monsters predominate (Including: Wraiths, giant scorpions, lycanthropes, gargoyles, white apes, 6th level fighters, 7th level magic-users). Notice how many of these require magic weapons to hit, or have energy drain or poison abilities, or are just generally very tough at this level.

I think I can come out and just directly say that this OD&D table was pretty much in error and not terribly well thought out. It just gets excessively tough really quickly; there's no balanced place for 2nd-level PCs to explore, for example.

Now let's look at Gygax's follow-up with the AD&D tables (stretched out from 6 to now 10 levels of monsters). Here, the 1st-level monsters are most likely at both the 1st dungeon level, and also the 2-3rd dungeon level category. Not until the 4th dungeon level are 3rd-level monsters more common than others -- and that's still the case at the 5th dungeon level. Rather oddly, low-level monsters continue to appear at every possible level of the dungeon. Clearly the advancing deadliness has been much toned down compared to OD&D. (Still, 2nd-level monsters fail to be most common at any level. And why are dungeon levels 2-3 singularly merged? Possibly an overreaction to the 2nd level jump in OD&D?)

I think this is a case where Holmes presents a reasonable, happy medium, one that seemed to escape Gygax as he veered from too-deadly in OD&D to somewhat too-fiddly and forgiving in AD&D. My personal preference would be an OD&D-style table (based on d6 and 6 levels of monster) that had a more regulated increase in risk level.

Alignment in MMOs

I don't play MMO's. I don't think many include a concept of alignment (hell, plenty of D&D players work to discard it). Turbine's Dungeons & Dragons Online does (in a fairly vanilla mechanical version as per 3.5E, noting that Evil alignments are prohibited); the same company's Lord of the Rings Online was originally slated to use basically the same mechanic, but had it yanked out during development. *

We'll stipulate that for most participants in these games, player-versus-player (PVP) combat is undesirable, but some small numbers (I've seen statistics saying 10% or less) do desire it. The major problem is that free-for-all PVP tends to cultivate "griefers" who beat up on new players/customers, take their stuff, and generally befoul the experience.

Let's meld the two issues into a proposed MMO mechanic.

Imagine that an MMO had a simple one-axis alignment; on character-creation, PCs are Lawful. At any point during the game, a PC can opt to switch to Chaotic, but this switch is irreversible. Lawful PCs are mechanically unable to attack other Lawful PCs; Chaotic PCs can attack, and be attacked by, anyone.

Suppose we also say that there's a very low-level spell (detect evil) that "marks" Chaotic characters for some extended time, making them officially open to attack by Lawfuls. Would that be functional? Discuss.

(* Full disclosure: My girlfriend worked at Turbine on the Asheron's Call game. I had an interview there to work on the AO live team at one point, and later I sent an inquiry about work on the DDO team, but didn't hear anything back about that.)

Reaction Tables

How much do you use Reaction Tables for the initial responses of D&D monsters? I don't very much. I kind of don't want half the monsters in every dungeon to all turn pacifist-friendly.

Interesting historical note: OD&D has such tables, but they are prefaced by the following text:

Monsters will automatically attack and/or pursue any characters they "see", with the exception of those monsters which are intelligent enough to avoid an obviously superior force. [OD&D Vol-3, p. 12]

Further down the page, you get a table for reactions of those "more intelligent monsters [which] will act randomly according to the results of the score rolled on two (six-sided) dice". This being 2-5 negative, 6-8 uncertain, and 9-12 positive, noting "The dice score is to be modified by additions and subtractions for such things as bribes offered, fear, alignment of the parties concerned, etc."

I'll emphasize the very limited extent to which monsters won't automatically attack, namely that they must both (a) be intelligent, and (b) be confronted by an "obviously superior force". Consultation of the random reaction table happens very rarely under this rule. I like that. (I'll point out that there's a different reaction table on Vol-1 p. 12, this one used if monsters are offered hire as henchman status, and this requiring similar alignment and offer of some award, etc.)

Now, in one example of several that I've pointed out before, as time advanced, the visually striking nature of the table/illustration became lodged in collective memory, while the introductory text governing its use was disconnected and lost from the whole.

For example, Holmes simply says this, having just introduced the concept of wandering monsters:

Obviously, some of these creatures will not always be hostile. Some may offer aid and assistance. To determine the reaction of such creatures, roll 2 dice... [Holmes, p. 11]

Holmes follows this with a copy of the OD&D Vol-1 table. Note that the requirement in which most monsters will automatically attack has been removed, implying that this roll should now be made for all monsters in the dungeon. (Or maybe it could be argued just for all wandering monsters?)

Gygax later writes this in the AD&D DMG:

Any intelligent creature which can be conversed with will react in some way to the character that is speaking. Reaction is determined by rolling percentile dice, adjusting the score for charisma and applicable loyalty adjustment as if the creature were a henchman of the character speaking, and the modified score of the percentile dice is compared to the table below... [AD&D DMG, p. 63]

This is followed by a broadly similar chart using percentile dice. Again, having edited out the introductory text from OD&D Vol-1, this passage indicates more widespread usage, for any creature that the PCs might possibly exchange words with. A modifier for Charisma is indicated (which is very much in the PCs' favor, if they have only the highest-Charisma PC speaking), but gone are the suggestions of modifiers for "bribes offered, fear, alignment", etc.

In general, I feel that these latter rules (which are all I had to consult circa 1980-2005) are too generous towards the PCs if used literally as written in the book, ultimately giving a 50/50+ chance for any dungeon monster to turn friendly. This is one of the many instances where I find the OD&D rule more direct and to my liking, intuitively the way I would want to play with most monsters I place engaging in "automatic... attack" except for exceptional cases where I decide some other possibility is in order.

Dante's Inferno

So I was visiting my folks' place the other weekend, and in the evening went hunting from the bookshelves for something to read. One thing I picked up was Dante's Inferno -- assigned in a class in college, I failed in a half-dozen attempts to read past the first 10 pages or so. Now 20 years later I've finally finished it.

(In hindsight, a major reason that I couldn't finish it before is that I've got a translation by Mark Musa for Penguin Classics -- pictured above -- and the guy went nuts with the annotations: 60-page introduction, header summary to each Canto, and Notes after each Canto, frequently longer than the text itself. The header summary in particular gives away all the plot in advance, and then you have to slog through the longer poetry about stuff you already know is going to happen -- that's what killed me in college. By avoiding those header summaries, I could read it the other week and find it fresh and compelling.)

Now, there's not a whole lot to say about it beyond what people like Milton, Longfellow, T.S. Eliot, Rodin, Mike Watt, and an imperial legion of literature PHDs haven't already said. But I figured it's worth a few bullet points here, seeing as it directly contributed its nine-descending-concentric-circles architecture to the D&D conception of Hell -- from Gygax's first presentation of the Outer Planes in Dragon #8, to devils in the AD&D Monster Manual, Greenwood's influential articles on the subject, and all the way to 4E today -- with some slight topical/naming rearrangements. (D&D's Heaven is similarly inspired by the structure of Dante's Purgatorio/Paradiso.) So here goes:

1. It's torture porn. There's no other way to put it. The truly enduring allure of the Inferno is the monumental creativity behind pages and pages and pages of ingenious, surprisingly graphic, ever-mounting tortures inflicted upon the damned in hell, and the quasi-ironic poetic justice (contrapasso) which relates each punishment to the associated sin and sub-sin. Much like a modern Saw movie, you can wrap this in a facade of moral meditation, but the deeper attraction is really not that. You get the same moral themes in Purgatorio and Paradisio, but most people don't bother to read those.
2. The classical allusions are great. For some reason it's still exciting (in a comic-book-crossover-kind-of-way) to see Dante's character running into, and interacting with, some legendary figure in each section such as Virgil, Homer, Odysseus, Achilles, Caesar, etc., etc. Dante sets an intriguing, powerful model for melding Christian with Classical mythology -- including positions for Cerberus, Centaurs, the Minotaur, Medusa, and the Titans in the Christian cosmos -- much like Original D&D's establishment of Catholic clerics adventuring against an almost all-Greek-myth cast of antagonists (OD&D Vol-1 and 2). However, I'm now enormously sensitive to the faultlines of this approach: Are the Centaurs in Hell being punished, or are they devils themselves? If the Titans (and others) still shudder from Zeus' casting them down into the pit, how is it that Zeus and the other Olympian gods are themselves missing from the cosmology? Stuff like that.
3. The 14th-century Italian references kind of suck. In contrast to the preceding, Dante's character actually spends more time constantly running into contemporary Florentines and other Italians, speaking with them at length, and grinding various axes against rivals, competing merchant clans, out-of-favor politicians, etc. These are a bunch of people you've never heard of before, and really couldn't care about -- much like a TV show with too many topical references, it's aged fast compared to the other parts, and it's rather a bore to slog through these sections. Unfortunately, somewhat more ink is spent on these characters than the classical ones above. (Kudos to the translator Musa from providing annotations to all of these, although the fact that he included equally-long notes identifying who are Caesar, Achilles, Hannibal, the Minotaur, etc., makes it look pretty goofy.)
   

Part of me is left with a desire to sit down and write a top-to-bottom D&D campaign directly out of Dante's Inferno (sticking more closely to the text than the D&D version), but possibly someone's already done and/or published that at this point -- and in addition, I'm sort of committed to avoiding the Christian church/mythology in my own games these days, so it wouldn't mesh very well with other stuff I do. The overall construction and specification of Dante's Inferno remains novel and absolutely compelling (particularly to a math-oriented guy like myself).

Here's a couple cool ideas I'd consider using in a D&D campaign right now:

• The circle of Sorcerers has this intriguing passage:
  

  They built a city over her dead bones,
  and for her, the first to choose that place, they named it
  Mantua, without recourse to sorcery. [Canto XX, lines 91-93]
  

  So, this has two interesting seeds within it. One is to make it a practice of founding your cities over the bones of dead wizards for some sort of protective-power effect (I'm quickly thinking of Lankhmar's lich-like defenders here). The other related practice is to require a divinatory spell (contact other plane) to actually get some higher power to tell you the proper name of the place. (As Musa writes in the notes here, "The customs of ancient peoples dictated that the name of a newly founded city be obtained through sorcery.")
  
  
• The other idea is how to name your devils -- specifically, pick some simple descriptive phrase and run it through an online Italian translator, and you get an authentic-sounding, baroque Hellish name (at least to my ear). That's effectively what Dante did for his Malebranche devils in Canto XXI, and of course those were transcribed directly into the writeup on the same kind of devil in the AD&D Monster Manual (p. 22). Some quick examples: "Strong Hand" = "Manoforte", "Knobby Leg" = "Manopolagamba", "Angry Face" = "Facciarrabbiata". (I suppose this will be a lot less impressive if you actually know Italian, but I'm fond of it.)

(As a final aside, my picking up Dante's Inferno doesn't have anything to do with the recent EA video game using the same title -- that's just a coincidence.)

DMG Appendix A

In the last post, I made some analysis of Gygax's Dungeon Geomorphs product. I've also been playing around recently with AD&D DMG Appendix A: Random Dungeon Generation. Let's use the insights to the former product to fill in some of the hidden assumptions in the latter. When using Appendix A, I would highlight or recommend the following:

1. To start with, you should normally begin by going directly to a random room on Table V. (The "Start Areas" on p. 169 are visually arresting, but that's actually a secondary, optional start possibility. You don't want to re-use those a lot.)
2. The tables probably generate more 45-degree passages and 20'-wide corridors than Gygax himself would actually use by default. Be ready to ignore or override those results a lot if they don't fit well into your map; in particular, I make all 45-degree passages automatically 10' wide (ignoring the fact -- as Gygax did -- that running along vertices on the graph paper, they're really just 7' wide).
   
3. Rooms and Chambers (square/rectangular) should, for convenience, always be set up on the cardinal axes -- if accessed off a 45-degree passage, you should probably automatically make them Triangular or Trapezoidal. In addition, all Triangular/Trapezoidal rooms may as well be right-angled, setting them along the grid axes, and giving them a single 45-degree diagonal wall. Any side passage or "door ahead" in a 45-degree corridor should be set along a cardinal-direction, unless it explicitly states the angle at which it should be.
   
4. By default, Rooms should have Doors, and Chambers should have Passages (i.e., non-door openings) as exits. This isn't explicitly stated anywhere, but it's implied in places like Table I (corridors empty into chambers but never rooms), Table II (doors open to rooms 4 times more often than chambers), and Table V-C (result of 19-20 indicates exceptional case of "door in chamber, passage in room").
5. Note that the treasure containment tables (Tables V-H through V-J) are copied verbatim from the earlier Monster & Treasure Assortment product. Tables V-I and V-J (guarded by/hidden in) stand out in Appendix A because they don't have any game statistics associated with the entries. Particularly for solo play, I recommend ignoring these tables (per the "if desired" note -- contrast to Table VII: Trick/Trap, etc.)
6. Also, when making Rooms/Chambers for solo play, I change the generation order to (i) Room shape/size on Table V, (ii) Contents on Table V-F, and last (iii) Exits on Table V-C, etc. This lets any fight be played out before consideration of egress, which cognitively feels better to me (e.g., see the recent discussion on when room size/detail description is appropriate).
7. Note the somewhat unusual secret-door detection rates (by d20) on Table VII, result 1-5. I use this for all indicated secret door checks in Appendix A.
8. Finally, I delete the entry on Table III for "passage X's", since I don't like how it treats cardinal-versus-diagonal passages asymmetrically (i.e., biased towards yet more diagonal passages).
   

Item (3) seems particularly important to me. When using Appendix A in the past, I would tend to get into a diagonal corridor (e.g., Table III actually generates more 45-degree side passages than 90-degree ones), and from that point on I'd be struggling to draw a whole connected region of rectangular rooms, chambers, and passages all diagonal to the graph paper. If you think about it, that really abandons all the advantages to drawing on graph paper in the first place.

If we instead re-set to the cardinal grid every time we enter a room or chamber, then we get more limited diagonal elements, less frustration for DM & players alike, and a dungeon much more like the designs Gygax had in mind when he was laying out maps such as those in the Dungeon Geomorphs and other products.

Dungeon Geomorphs

This is the first of a two-part post on early dungeon layout tools, both by Gary Gygax. This first (longer, I expect) post is on the Dungeon Geomorphs product crica 1976-1980. The second one will be on AD&D DMG Appendix A: Random Dungeon Generation, and what some of the unstated assumptions might be for that resource.

The Dungeon Geomorphs were originally 3 separate products published in 1976 and 1977. (My digital version of the collected set -- as shown above -- doesn't actually credit Gygax anywhere, but his name was on the cover of the earlier sets that you can see at the Acaeum site over here.)

Thus, there are 3 different "sets" of geomorphs, identified as "Basic Dungeon", "Caves & Caverns", and "Lower Dungeons". Each has 15 different sections of dungeon architecture (lettered A-O) that can be combined and connected in different ways to create unique dungeon layouts. Each page of the product has 3 sections: 2 sections 21x21 squares each, and 1 section sized 10x42 squares (each square 10', per the introduction). All together, my estimate is that there's upwards of 1,000 separate rooms and passages pictured in the Geomorphs, so it provides a good look at Gygax's design sensibilities at the time.

First, a quick sense of each of the different set types:

1. Basic Dungeon. The first thing that strikes me here is that almost the entirety of each map page is covered with accessible rooms -- there is almost no "dark space" of solid rock to speak of. (Module B1, 1st level is the only other dungeon product that looks similar to me.) While it's easy to get lost here, the overall sense is one of "openness", of being able to access every part of the map with some effort. There are lots of rooms here (estimate: 35 rooms and 20 passages per map section).
   
2. Caves and Caverns. As to be expected, these levels have irregular, rough-hewn tunnels and cave systems. There's a lot more dark space, as adjacent areas are almost always separated by at least 10' of rock (instead of thin one-line walls like in the Basic Dungeon). Caves tend to be larger than the rooms elsewhere, and unlike the other sets, there are no doors anywhere. Due to the larger sized caves, there are far fewer of them per page (estimate: 6 caves and 20 tunnels per section).
3. Lower Dungeons. The lower dungeons have more of a "claustrophobic" feel to them. There's more dark space than in the Basic Dungeon (a balance between thin-line and 10' block room dividers), and I think the rooms are, on average, smaller. There are more odd-shaped rooms, zig-zag passages, several isolated 30' circles (possibly chutes/shafts bypassing the level?), a number of 10x10' room maze areas with many doors, etc. There are more rooms than in the caves levels, but fewer than the Basic Dungeon (estimate: 20 rooms and 20 passages per section).
   

Now, considerations of features shared across the different set types:

Doors: Excepting the Caves levels, there are doors (and secret doors) indicated throughout the different sections, although some rooms are missing doors, and thus disconnected from the rest. (The Introduction makes clear that you're expected add doors, delete or modify areas, etc.) There are a small number of these disconnected rooms in the Basic Dungeon, and a larger number of them in the Lower Dungeons areas (some sections more than others).

Passages: The vast majority of passages, corridors, and tunnels are 10' wide, rarely 20', and never any larger than that. About half of the Basic Dungeon tiles (8 of 15) have a single straight piece of 20' wide corridor, stretching about two-thirds the way across the tile. Arguably, there are no 20' corridors in any of the Caves or Lower sets; there are some 20' wide areas which might be interpreted as either cave/rooms or corridors, but in any case they're much shorter than in the Basic Dungeon. Even in the Caves levels, there are many 10' wide tunnels that run straight along a cardinal direction (to me, reminiscent of the sample tunnel sections in the module D1-3 product).

Central Areas: A common feature shared across all the sets is that each provides 3 sections that can be joined to create an enormous central area location -- perhaps a grand Arena/Cavern/Temple area. (Respectively these are sections ILF, ILO, and ILO in each of the 3 sets.) If joined, each of the versions of the huge central feature is about 22 squares on each side or somewhat larger (i.e., over 200 feet square).

Diagonals: One issue that motivated this overall article was the burning question: "How many diagonal features did Gygax expect to use on a typical dungeon map?". While design elements in the four cardinal directions (NSEW) are easy to deal with on graph paper, those on a non-cardinal 45 degree axis (NE, NW, SE, SW) tend to aggravate me, my players, my geometry sensibilities, and my software projects (see here). So I'll pay particularly close attention to those elements, to see how widespread they were expected to be.

Here's an overview of the diagonal situation: (1) While diagonal passages appear on almost every dungeon section, they are limited in scope -- usually only 30' of corridor or so. (2) Diagonal passages are always 10' wide, never a 20' wide passage or anything bigger. And importantly: (3) Practically every square/rectangular room in the product (the vast majority of rooms) is oriented in the cardinal direction, regardless of whether the approaching corridors are on a diagonal or not. (There are only two exceptional occurrences of square rooms oriented on the diagonal -- one in Basic Dungeon Section N, upper left corner; and a pair of connected rooms in Lower Dungeons Section C, upper left corner.)

Finally, a listing of recurring unusual room shape elements (having noted that the vast majority of rooms are square or rectangular in shape):

1. Circles. In the Basic Dungeon, there are some 20' wide circular areas, each one a dead-end with no door (4 of these). There are a few 30' wide round areas (3 of these), in each case the nexus of 4 diagonal corridors. As noted earlier, the Lower Dungeons have some 30' wide circular rooms (3) that are almost totally disconnected from their surroundings. There are also 3 zones of sweeping, curved corridor around these areas.
2. Triangles. Where a diagonal corridor is placed, this tends to create a triangular room on each side, at least in the Basic Dungeon sections (or else possibly a trapezoid; see below). Practically all of these are right-angle isosceles triangles (i.e., a right angle and two equal sides; or, a 45-45-90 degree triangle). Generally, the two equal legs are on the cardinal axes, with the hypotenuse on the diagonal -- in the Basic Dungeon, this is true 46/53 = 87% of the time, while in the Lower Dungeons it's only true 14/27 = 52% of the time. In the Lower Dungeons, it's common to construct triangular rooms by chopping a 20x20' square room in half (5 instances) or to cut one large "cardinal" triangle into two smaller "off-cardinal" triangles (3 instances).
3. Trapezoids. Where a diagonal corridor doesn't create a triangular room to the side, it might create a right-angle trapezoid -- almost a rectangle, but with one diagonal wall (at least in the Basic Dungeon). In almost every case of this, 3 walls are connected by right angles and lay in the cardinal directions; the 4th connecting wall is on the 45-degree diagonal.
   
4. Octagons. There are several locations in the Basic Dungeon (5) with 30'-wide octagons, always used in a similar fashion to the 30' circles -- as the junction for a 4-way corridor intersection. In these cases, the corridors are always running in the cardinal directions (not diagonal).
5. Stepwise. This would be a room that was perhaps trying to be triangular or trapezoidal, but was made "pixellated", with one or two of the walls running zig-zag along the boundaries between grid squares. This happens several times (6) in the Lower Dungeons.
   

Typical usage of each of these element types can be seen below:

Booming Boars

A bit of confusion today, I think purely due to my own curtness, as to whether I think giant boars are a good idea for a monster or not. As penance I'll post what I've been working on today a bit earlier than planned. Everything in the quote box below is designated as Open Game Content, as per the Open Game License Version 1.0a:

BOOMING BOARS

Number: 1-6
Armor Class: 5
Move: 15"
Hit Dice: 5
% in Lair: Nil
Treasure Type: Nil
No. of Attacks: 1
Damage: 1d6+2

Booming boars appear to be large but possibly normal boars or warthogs, 4' high at the shoulder. However, they have an explosive sonic/belching attack that can affect anyone in a cone-shaped area 6" by 3". Targets must save versus paralysis or become deafened (1d6 turns) and stunned (1d3 rounds). Individual boars can only belch once per day, but those in a group (called "sounders") may stagger their sonic attacks over several rounds (roll 3-in-6 for each boar to belch in any round). They are themselves immune to sonic attacks.

Radioactive Boars

Oddly, just last night I was scratching out the "Giant Hogs" entry in my OD&D encounter tables (actually Sup-I) as being too ridiculous for me -- and then I run into this article on the proliferation of actual "Radioactive Boars" today in Germany, here (a long-term effect from the Chernobyl meltdown). So perhaps that's inspiration if you run a post-nuke flavored campaign.

EDIT: I'm just talking about them being so common deep in dungeons, not that I'd avoid using them in general.