Alter Self Spell
Alter Self Description: You assume the form of a creature of the same type as your normal form. The new form must be within one size category of your normal size. The maximum HD of an assumed form is equal to your caster level, to a maximum of 5 HD at 5th level. You can change into a member of your own kind or even into yourself.
You retain your own ability scores. Your class and level, hit points, alignment, base attack bonus, and base save bonuses all remain the same. You retain all supernatural and spell-like special attacks and qualities of your normal form, except for those requiring a body part that the new form does not have (such as a mouth for a breath weapon or eyes for a gaze attack).
More: D&D Spells for Alter Self