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
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.
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.
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.