Spells Through The Ages – Animal Growth

This week we're looking at the 5th-level D&D wizard spell, animal growth. No need for artificial growth hormone with this bit of magic in your book. But how did the spell itself grow over the years?

Original D&D

Growth of Animals: A spell which will cause from 1-6 normal-sized animals (not merely mammals) to grow to giant-size with proportionate attack capabilities. Duration: 12 turns. Range 12".

Originally Gygax called the spell growth of animals. It can affect 1-6 animals; but is that a random roll, or at the election of the caster? Of course, the biggest problem is that while the spell says the targets "grow to giant-size", OD&D nowhere provides concrete statistics for any giant animals. There is one line in the table of Vol-2 that simply says "Variable" for all statistics; and a short block of text that essentially says they could be, well, anything at all. So with this spell the DM and players are utterly on their own about negotiating what benefit the caster gets. (Note that this spell was one of those excluded from Cook's D&D Expert rules, so next we'll go directly to the AD&D line.)

AD&D 1st Ed.

Animal Growth (Alteration) Reversible
Level: 5
Range: 8"
Components: V, S, M
Casting Time: 7 segments

Duration: 2 rounds/level
Area of Effect: Up to 8 animals in a 2" square area
Saving Throw: None

Explanation/Description: When this spell is cast, the druid causes all animals, up to a maximum of 8, within a 2" square area to grow to twice their normal size. The effects of this growth are doubled hit dice (with resultant improvement in attack potential) and doubled damage in combat. The spell lasts for 2 melee rounds for each level of experience of the druid casting the spell. Note that the spell is particularly useful in conjunction with a charm person or animal or a speak with animals spell. The reverse reduces animal size by one half, and likewise reduces hit dice, attack damage, etc.

Above, we're looking at the druid-spell entry, to which the magic-user section back-references. The name is now animal growth, as it will be in all later editions. The number affected has increased from 1-6 to a maximum of 8 (technically by the wording "all animals" not modifiable by the caster). The effect has changed in kind of a weird way: in OD&D, it said that animals "grow to giant size", even though OD&D lacked explicit giant animal stats. Here in AD&D, you now do have a catalog of specific giant animals available (via the Monster Manual), but the spell effect does not refer you to them, instead saying "effects of this growth are doubled hit dice" -- which is now a whole new problem, because what the MM generally does not have are the stats for the normal version of the animals which are getting doubled here (think: badgers, weasels, spiders, centipedes, etc.). That is: the spell zigged while the monsters zagged. Later on, the Monster Manual 2 gave lots of entries for "normal" animals that I suppose you could use as a basis for the wording of this spell. To me it seems like the best solution would be to extrapolate away from the exact language above and use those giant entries in the MM. But fundamentally this "doubling" rule will be retained consistently in 2E & 3E.

AD&D 2nd Ed.

Animal Growth
Range: 60 yds.

Duration: 1 rd./level
Area of Effect: Up to 8 animals in a 20-ft. cube

When this spell is cast, the wizard causes all designated animals, up to a maximum of eight, within a 20-foot-square area to grow to twice their normal size. The effects of this growth are doubled Hit Dice (with improvement in attack rolls) and doubled damage in combat. The spell lasts for one round for each level of experience of the wizard casting the spell. Only natural animals, including giant forms, can be affected by this spell.

The reverse, shrink animal, reduces animal size by half and likewise reduces Hit Dice, attack damage, etc.

The component of both versions of the spell is a pinch of powdered bone.

This is almost a direct copy-and-paste from 1E with some very minor edits (changing area in scale inches to feet, etc.). The "double Hit Dice" rule is kept intact. Cook does change the wording from "all animals" in the area to "all designated animals", so the caster can now clearly choose how many to gigantify.

D&D 3rd Ed.

Animal Growth
Level: Drd 5, Sor/Wiz 5
Components: V, S
Casting Time: 1 action
Range: Medium (100 ft. + 10 ft./level)
Targets: Up to one animal/two levels, no two of which can be more than 30 ft. apart
Duration: 1 minute/level
Saving Throw: None
Spell Resistance: Yes

A number of animals grow to twice their normal size. This doubles each animal's height, length, and width, increasing its weight by a factor of eight. This increase in size has a number of effects:

Hit Dice: The creature's HD double, doubling the creature's base attack bonus and increasing its saves accordingly.

Size: The creature's size increases one step. This increase reduces its AC (according to the new size), reduces its attack bonus (according to the new size), affects its ability to grapple, and so on. The creature gains an enlargement bonus to Strength and Constitution scores, and its damage with natural attacks increases. This spell does not affect Colossal creatures.

When the spell ends, the creature's hit points return to normal, and all damage the creature has taken while enlarged is divided by 2.

The spell gives the character no special means of command or influence over the enlarged animals.

This version still maintains the kernel of the spell since 1E -- doubling the normal creature's hit dice (and 3E did provide a fairly extensive list of normal animals in its core rules: see 3E Monster Manual Appendix 1.) The number grown has changed to a variable one-per-two-caster-levels. And consistent with 3E's elaborate rules for monster creation and size changes, you now have a whole gauntlet of math calculations that you're supposed to make from the spell: first increasing hit dice, base attack bonus, and saving throws (due to the hit dice basis). Then reducing AC and attack bonus (due to size penalties). Then increasing Strength and Constitution and subsequent attack bonus and damage (due to size bonuses). No matter how you slice it, if you do this extemporaneously during a session at the table, play will be halted for some extended amount of time while you assess these changes, which I personally find to be highly unacceptable. If I recall correctly, a lot of published 3E material would pick one "favored" type or companion for NPCs and present the long stat block for when that animal gets animal growth cast on it. In some sense you'd have to admit that the original simplicity of "double stats on the fly" (to the extent there was some source animal to double in the first place) is in fundamental conflict with the strictly-constructed 3E system for creating and calculating monsters.


In early editions (0-1-2E), how did you come up with stats for the grown animals? Did you actually take normal stats and double them, or did you turn to the Monster Manual and use the appropriate giant type? Were you ever troubled by the lack of an upper bound on the hit dice possibly created (for example: 15HD giant sharks and sea turtles in the AD&D MM)? Were you able to use the 3E spell on the fly as written at the table, or did that grind your game to a halt?


  1. I can't ever remember seeing this one used, probably because A) it's not present in B/X (which is how I started...I skipped OD&D), and B) we never had any druids PCs in our AD&D campaigns (other than the odd 1E bard, I suppose).

    However, I'd lie to point out that if you double the height, length, and width of a creature then you are increasing its volume by a factor of 8, not 2 (2x2x2), and HD should probably be increased accordingly.

    A good example of this is the hill giant: being 12' tall, it's twice the height of a man and (presumably) proportioned the same in width and length. It's HD? Eight...eight times that of a (1HD) human.

    Just saying.

    1. [*ahem* that should be "I'd LIKE to point out..." I'm not lying. Jeez!]

    2. Note that animal growth is on the wizard (magic-user) spell list in all the editions mentioned above.

      I'd disagree on the x8 hit dice assessment. At best, strength comes from bone & muscle cross-section, i.e., a 2D factor, so x4 would be an upper bound, explaining why small insects are proportionally the strongest as compared to the 3D weight factor (link).

      But the precedent in the D&D rules is mostly that hit dice are indeed proportional to height. The average hit dice for man-sized creatures is actually 4 hit dice; at large/giant-sized it's 8; and so forth. We might say that humanoids are unusually weak for their size (compare men to apes), unless they have special training and advance levels. (Prior analysis on this point: link)

    3. The average HD for a man-sized creature is 4HD?! In which edition? I think his math may be off.

      Okay, I read the links and I think there’s a little misinterpretation here. There’s a difference between “man-sized” and “medium-sized.” A bugbear (for example) is larger than man-sized, as is a gnoll (for example) with proportionately larger HD. “Medium-sized” is a definition for 3rd edition D&D which likes to use a lot of categories (fine, diminutive, large, huge, gigantic, etc.) combined with monster “type” to give a more systematic approach to their mechanics (a la GURPS or something). A man-sized creature (i.e. something on the scale of a human) has and has always had 1HD unless it is (as Williams states) especially tough or formidable…like supernatural creatures. Lumping things like a “death salad” (15HD) or astral deva (12HD) or trumpet archon (12HD) or any number of “medium-sized” monsters into the same category as an orc and saying “the average HD for a man-sized creature is 4” is patently ridiculous. A medium-sized Godling with 100HD may skew the average for the size category of monster; that doesn’t mean the average man-sized humanoid can take 5 or 6 dice of damage or that humans are “under strength.”

      To put it more succinctly: I disagree with your assessment that the D&D precedent is to base HD on height. And I don’t think Super Dan’s article is incredibly pertinent here as I was talking about “normal” humanoids (like humans) rather than supernatural demons or monsters that fall into a "medium" size category…but I wasn’t really discussing 3rd edition equivalents anyway.

      [a giant insect is much larger than 8x its normal mass...but then a normal-sized ant or fly would have less than "1 hit point" (how many normal ants could you kill with one well-placed blow of a war hammer to an anthill?]

      3rd Edition would have been better served to leave out the “double HD” entirely and simply used the size increase (with equivalent benefits) seeing as how the 3E MM already set standards as to how changes in size affect a creature’s stat profile.

    4. I think trying to find a connection between size and number of hit dice is dubious at best. I don't think there was that much thought put into it and lets be honest, these are fantasy monsters that don't abide by modern day physics. The stats for a monster are often internally consistent even if they aren't consistent with other monsters.

      If it says to double hit dice I'm inclined to just double everything else since those values are typically a ratio of the hit dice and more consistent. If the bonus to attack is 2/3 the creatures hit dice than just keep the same ratio using the new hit dice.

    5. FYI, Superdan.net is me also. Yes, the hit dice average for Medium creatures is also 4 in AD&D; the monsters and core stats are mostly copy-and-pasted between editions.

      Linked below you can see a spreadsheet confirming that for all 1E AD&D monsters (includes MM, FF, MM2 books). Average for Small: 2HD, Medium: 4HD, Large: 8HD (same as 3E).


  2. I started play with Mentzer's BECM series, and his Expert set DOES include the spell where BX does not. It's a third level cleric spell, range 120', duration 12 turns, affects one animal only, and doubles its size which in this case simply means giving it double damage and double carrying capacity. Hit points and armor class are explicitly stated as not changing.

    So that's how I've always run the spell (never had anyone try to cast it when I ran AD&D or 3E).

    1. Hunh. Very different with the one-animal only effect. Thanks for that info!

  3. I would presume the Chainmail version of the spell would be something like. "Place one of your pets on the sand table."

    1. And here's where I post Internet cat picz all day. Looky.

    2. A: You need to add a giant Aqua-cat to your encounter tables if you ever run "Corsairs of Medero" again.

      That ship full of dudes looks really cool, larger than life furry terrain features notwithstanding.

      B:What else would the internet possibly be for?

      C: It's an effective unit, but its loyalty is entirely dependent on who feeds it, and even then it's provisional loyalty at best. :)

  4. Never seen it cast. Was not even aware it was a spell.

  5. I am all for at the table, easy calculations be it x2HD or HP/ or +2 to certain values (Saves, AC), whatever.
    FWIW in my home game I have the usual animals stated out, but I also have a number of generic animal stats "Medium Sized Predator" "Small Herbivore" in case I need a random critter on the fly.

  6. I don't have any experience with the earlier versions of the spell but my table saw the 2E version used A LOT. It was one of the most popular non-Wizard spells.

    Per the spell description we doubled the hit dice, doubled the damage done, and I if I remember correctly we doubled the attack bonus. The bonus to attack is the only fuzzy number since they are not as clear about it but doubling it seemed reasonable.

    For 3E we did not see it used as often for some reason. When it was used I used a hodge podge of implementations. If there was a dire version of the animal, I used that. If there wasn't I might just double their stats if it seemed OK, and otherwise I would use the methods described in the spell if I had time. I eventually put together a table of the common animals with their adjusted stats so it was available if needed, but it never was. I think most of the time I was able to use a dire version of the animal or the stats for a dire animal that was close to what I needed.

  7. I also have no issue with the lack of upper bound on hit dice. We are using magic to increase the size of some potentially impressive creatures. Doubling the size of an elephant or great white shark should lead to some pretty impressive creatures. I'm OK with that.

    Let me ask you this, does the lack of an upper bound on hit dice bother you? If so, why? I'm curious.

    1. Yes, it bothers me; it seems unbalanced at this level. Creating multiple 20+ HD monsters is out of scope for other spells at this level.

      It's the same problem as polymorph (link; esp. consider Andy Collins' rant at the end). In particular, if a DM introduces a Tyrannosaur or some new 50HD monster, he'll surely overlook the fact that this spell can turn them into 100 HD creatures to the benefit of the players. Unbounded power are always unbalanced.

    2. I'll add that I'm interested and surprised in this discussion at how many people were accustomed to using the spell on already-large animals. I seriously never even thought about anyone using it that way -- taking cues from the OD&D & AD&D monster lists, I always assumed that "giant animal" meant something that was formerly small and inoffensive, blown up to scary size.