This spell is most commonly used on warriors in the pursuit of some heroic deed. Spirit animal form can be cast upon the self or another willing person. After entering a trance that lasts at least one hour, the subject changes into a typical member of his or her spirit animal's species. For all intents and purposes, the subject becomes that animal, receiving all of its normal attributes and abilities, save that intellect is retained. The transformed person uses the spirit animal's combat tables, but the saving throw tables appropriate to his human form. Everything worn or carried becomes part of the animal form, and is still with the subject upon returns to normal form. The spell lasts 1d10 days, and neither the caster nor the subject has any control over when it will expire.
This spell cannot be used to assume the form of supernatural or supernaturally large animals, such as thunder birds. If such an attempt is made, the receiver assumes the form of a similar type of creature – in the case of thunder birds, for example, an eagle.
Notes: Common for Amerind cultures (originally from Legends & Lore).