Assume Appearance

This spell functions similarly to the Change Appearance option of alter self, except for the following differences.

You assume the exact form of a deceased Small or Medium creature of the humanoid type. Your voice changes to match that of the form you assume. The creature whose form you assume must be dead and you must have access to its fresh corpse (either dead less than 24 hours, or preserved via gentle repose or similar effect). Any attempt to copy the form of a living creature causes the spell to fail. You do not have access to the assumed form’s abilities, memories, mannerisms, or speech patterns. 

Effects that dispel or see through illusions do not detect your change in appearance.