Monster Memorization
Universal 3
Target: One dead creature
Range: Touch
Duration: Instantaneous
You touch a dead creature, gaining knowledge of its racial abilities. This creature must have been dead for no longer than one day per caster level. You may memorize any number of monsters, provided their total hit dice does not exceed four times your caster level. You may voluntarily forget one or more monsters when attempting to memorize a new one. Should you attempt to memorize a monster with more hit dice than yours, the attempt automatically fails.
Memorizing a monster has several benefits:
-You automatically succeed at any knowledge check regarding the racial abilities of memorized monsters, even if you have no ranks in the appropriate knowledge skill.
-You gain a +2 insight bonus to armor class and saving throws against the attacks of memorized monsters.
-Memorized monsters forced to make saving throws from one of your spells or abilities do so with a -2 penalty.
-You may assume a memorized monster form with an appropriate spell from the [Polymorph] subschool, using the normal rules for that spell (including limitation on hit dice and creature types).
-When preparing or casting spontaneously a Conjuration spell that calls or summons a memorized monster, the spell is treated as one level lower. Spells prepared in this way can only summon or call memorized monsters.
--
Polymorph would let you assume the form of memorized monsters. Also, possible interaction rules with Modify Memory, like losing CL worth of memorized HD or that person memorizing one of your memorized forms, provided they have the appropriate hit dice.