Oozes Through the Ages

Gygax liked his oozes. Most of the monsters in Original D&D (Vol-2) were either creatures out of Greek myth, or else monsters from Tolkien. The ones that were new to the game itself, created by Gygax, were the "cleanup crew" of scary amoeboids: ochre jelly, black pudding, green slime, and gray ooze. I got looking at these the other day and was surprised at how vague their functioning was, and how much they varied between editions. We've pointed out before that the Black Pudding is actually one of the most powerful monsters in the original game. Let's dig a bit deeper.

Original D&D

BLACK (or GRAY) PUDDING: Another member of the clean-up crew and nuisance monster, Black Puddings are not affected by cold. It is spread into smaller ones by chops or lightening bolts, but is killed by fire. Black Puddings dissolve wood, corrode metal at a reasonably fast rate, have no effect on stone, and cause three dice of damage to exposed flesh. If an armored character runs through a Black Pudding the monster's corrosive power will eat away the foot and leg protection of the armor so that it will fall-away next turn. Black Puddings can pass through fairly small openings, and they can travel as easily on ceilings as on floors.

One of the things I like about OD&D is that the monsters are sorted by category (all the humanoids, then all the undead, etc., usually by increasing power level). This makes it a bit easier to assess the common themes and features, and their differences, in monsters of a particular class. For space purposes I've just excerpted the Black Pudding above, the most powerful type, but you can see the others on the same or flip page in Vol-2 (p. 19-20), and they generally have the same format of description. The description specifies what kinds of attacks have effect, what kinds of materials are dissolved, and how much damage the thing does to flesh per round. Note that in OD&D, the only attacks that do damage in the system are of type fire, cold, lightning, or martial weaponry; when this was copied to future editions, it looked a bit strange, for not mentioning all the other types of damage that then existed. Here's a summary of the traits of the different oozes in OD&D, ranked in increasing level:

Note that in every case, as hit dice improve, so too do movement and armor class (monotonically). As noted, Black Pudding is the most powerful type -- immune to all attacks except fire exclusively (consider: what if you encounter one underwater?), dissolving all materials (except stonework), and doing the most damage of any creature in the game (3d6). The ochre jelly is like a half-strength pudding; vulnerable to twice the attacks (fire and cold), no effect on twice the materials (metal and stone). Gray ooze is effectively the inverse of ochre jelly; immune to the attacks that harm jelly, harmed by jelly's immunities, and reversed effect on non-stone materials (swapping wood for metal consumption). Green slime is the dumb, immobile cousin; harmed by the same attacks as jelly, and consuming all materials except stone.

Excepting the jelly, each of these types makes noise about eating away a character's metal armor, but the mechanic is left vague, possibly for each DM's adjudication on the fly. Reading the Black Pudding text above, I could imagine a whole host of possible ways of ruling on it:
  • Ooze makes normal to-hit rolls.
  • Ooze ignores armor for hits (always AC 9)
  • Armor is corroded only on a normal hit.
  • Armor is corroded on a miss (i.e., blocked by armor)
  • Weapons may or may not corrode on a hit.
  • Gray ooze, affected by "cuts and chops" may or may not only allow hits by swords and axes (disallowing clubs, spears, missile weapons). 
 What to do? So, I was looking to other editions for guidance.

Basic D&D

Gray Ooze: This seeping horror looks like wet stone and is difficult to see. It secretes an acid which does 2d8 points of damage if the gray ooze hits bare skin. This acid will dissolve and destroy magic armor in one turn. After the first hit, the ooze will stick to its victim, automatically destroying any normal armor and doing 2d8 points of damage each round. Gray ooze cannot be harmed by cold or fire, but can be harmed by weapons and lightning.
Holmes (1978), as usual, only restates what is in OD&D, with most of its oddities still intact. The text above is from Moldvay (1981), and the new feature that he has introduced is the fact that the ooze is sticky: "After the first hit, the ooze will stick to its victim, automatically destroying any normal armor and doing 2d8 points of damage each round," which is not something I would have ever intuited from the OD&D description. However, this particular feature is not included for ochre jellies in the same text, or for black puddings in Cook's Expert rules. These descriptions remained fixed through the Mentzer and Allston editions.

AD&D 1st Ed.

BLACK PUDDING: The black pudding is a monster composed of groups of single cells. It is a scavenger/hunter found only in underground areas normally. The body structure of a black pudding  is  such that it con pass (flow) through narrow openings (such as a  1"  crack under a door). The monster travels equally well on walls or ceilings as well as floors. Its tiny mouths and saliva do 3-24 hit points of damage per melee round to exposed flesh. If the monster needs to dissolve wood in order to obtain food, it can eat away about a two inch thickness of wood equal in area to its diameter in  1  melee round. Black puddings also eat away metal with their corrosive saliva: Chainmail in 1 melee round, plate mail in 2, and an additional melee round for magical armor at a rate of 1 melee round for each plus of armor. Thus, +1 magic (plate) armor would have to be in contact with a black pudding for 3 melee rounds before it dissolved. If chopped or struck, the monster is broken into two or more parts, each able to attack...
In the AD&D Monster Manual, we get a little more info about how quickly the pudding eats armor (chain in 1 round, plate in 2 rounds... note that in OD&D the text here said "turn", which I argue meant a Chainmail-style single 1 minute of combat at the time of writing). But this doesn't help resolve the question of exactly when armor starts to corrode, or the other questions noted above. Gray ooze refers back to this text for its own armor corrosion; it suggests for the first time, "Note, however, that in the latter case the weapons striking the creature may corrode and break.", but is not explicit about when or how likely that is to occur.

AD&D 2nd Ed.

The 2E descriptions show no important differences from the 1E text. The effective attacks, damage, materials consumed, and time to corrode metal are all exactly the same. No further detail is given on when to adjudicate the corrosive effects of the oozes.

D&D 3rd Ed.

Black Pudding

Improved Grab (Ex): To use this ability, the black pudding must hit with its slam attack. If it gets a hold, it can constrict.

Acid (Ex): The pudding secretes a digestive acid that dissolves organic material and metal quickly. Any melee hit deals acid damage. The pudding’s acidic touch deals 50 points of damage per round to wood or metal objects. The opponent’s armor and clothing dissolve and become useless immediately unless they succeed at Reflex saves (DC 19). The acid can dissolve stone, dealing 20 points of damage per round of contact. A metal or wooden weapon that strikes a black pudding also dissolves immediately unless it succeeds at a Reflex save (DC 19).

Constrict (Ex): A black pudding deals automatic slam and acid damage with a successful grapple check. The opponent’s clothing and armor suffer a -4 penalty to Reflex saves against the acid.
Split (Ex): Weapons deal no damage to a black pudding. Instead the creature splits into two identical puddings, each with half the original’s hit points (round down). A pudding with only 1 hit point cannot be further split.
Now with the 3rd Edition game, we do get added information that perhaps answers the questions we've been asking since OD&D. Black pudding is given abilities of "improved grab" and "constrict" that fold its mechanic into the more general rules on grappling in the 3E system; the monster must first hit, then can hold an an opponent as long as they do not counter, but require an additional check each round to actually do damage. In this sense it is "sticky" in a way only previously seen in Moldvay's gray ooze text. Weapons explicitly need a saving throw on contact or else they, too, corrode away. In 3E, each of the oozes considered here -- black pudding, ochre jelly, and gray ooze -- all work in this fashion. (In this edition, green slime is removed from the monster list and placed in the DMG under "Organic Hazards").

Poll Results

I asked my list of questions about ooze corrosion on the Facebook 1st Ed. AD&D group. This did not get nearly the attention that some other poll questions did (like, e.g., the question on how to adjudicate damage from dragon breath) -- seemingly this was not an issue that most people had strong opinions about. The majority choice, however, surprised me:

I say that this is surprising because -- while the group is dedicated to 1E AD&D rules, and is often downright militant about those texts' rulings -- in the case the preferred rule was the one from Moldvay's B/X (and echoed in 3E). Of the 26 respondents, most (54%) do like their puddings and oozes to be "sticky", which is not a trait suggested in either OD&D or AD&D. Only about one-quarter (27%) require the metal armor to fall off before attacking the "bare flesh". Only a single person was fond of corroding weapons that strike the ooze. No one selected any of the variant options for assessing when an ooze strikes a victim, or possibly corroding armor when failing to hit the person wearing it.


While OD&D/AD&D is ambiguous about adjudicating ooze armor corrosion, the editions that are explicit -- B/X for gray oozes, and 3E for all of the types -- make the oozes "sticky", effectively grappling victims automatically after the first hit; and it seems like the cultural memory of even AD&D players has incorporated this ruling. Perhaps this is the best way to rule on the creatures because, after all, a "grappling" type attack is in fact how real-world amoebas really capture their prey.

What do you think? Any other possible adjudications that I've overlooked?


  1. I've always presumed that the various puddings, especially the ochre jelly with its vulnerability to cold, were inspired from that old 50s film, The Blob. As such, I've modeled the behavior and such of jellies, oozes, and puddings on this creature (which includes some "sticking" scenes).

    On the other hand, I've always treated green slime, more or less, like an "environmental hazard" (similar to yellow mold), probably because of its depictions in Marvel comic book advertisements of the early 1980s (though also because of the way it is presented in most adventure modules: as a static obstacle, rather than a wandering destroyer).

  2. I wouldn't be at all surprised if Gygax drew his inspiration for the Black Pudding from the Clark Ashton Smith short story "The Tale of Satampra Zeiros". (http://www.eldritchdark.com/writings/short-stories/208/the-tale-of-satampra-zeiros)

    Or another strong contender is the 1953 story "Slime" by Joseph Payne Brennan, which you can find here: (http://www.www3.reocities.com/Paris/villa/4018/texts/Slime.html)

    I first ran across the latter one in an Alfred Hitchcock anthology called "Alfred Hitchcock's Monster Museum" when I was in elementary school and it gave me the willies.

    While I have no doubt "The Blob" was probably fodder for the profusion of D&D jellies, slimes, and oozes, similar creatures seemed to slither thru the general science fiction pulp zeitgeist before that.

    1. Oh wow, those are great references!

    2. They certainly seem to point to why the black pudding is such a heavy hitter, monster wise. If "Satampra Zeiros" doesn't read like a prototypical dungeon delve gone bad I dunno what does.

  3. I like the simplicity of "if it hits, it sticks", though I would be inclined to rule that it has to eat through armor before damaging flesh (gotta give the warriors a chance)

  4. "The Ecology of the Black Pudding" appeared in Dragon Magazine #219 (July 1995), visible here: