kmdietri
Explorer
Alternate Form (Su): An imp can assume other forms at will as a standard action. This ability functions as a polymorph spell cast on itself (caster level 12th), except that an imp does not regain hit points for changing form, and an individual imp can assume only one or two forms no larger than Medium. Common forms include monstrous spider, raven, rat, and boar.
If a character wants to play an imp what would you rule the forms it could take are? These all sound like suggestions as opposed to hard and fast rules.
IF anyone knows what it says in the Savage Species under the Imp character chapter that would help.