I did one for a Chuckie-based one a while ago. Except her soul was pertinently infused to a barbie doll.
Illithds: These octopuss-headed creatures has great psionic power and enjoy eating brains so that could be of use. Or for a silly twist one of these Illithids get abandoned and injured, but thanks to the All-Star's kindness, he was brought pack to health and found that he really liked dodge ball. Combine Psionic powers, a single-minded drive and a devious mind an all shall be fun.
Chain Devil (just for the look alone.) http://forgottenrealms.wikia.com/wiki/Chain_devil
Harpies: Great fun, especially if they like to fancy themselves as the monster version of Sex and the City.
Medusa: The twist is that she's blind and is unable to use her gaze attack, but takes up for it with the snakes being able to streach to long distances to attack, go long distances or try a new fashion style.
Nightmare (The horse) These nasty creatures make fearsome rides.