A girl almost (if not more) crazy than the Joker, she has the scars of her ex set into her skin. (I mean that literally, he bleached her skin in a vat of chemicals!) She always seems excited and giggily no matter the situation and rarely shows any negativity. She has a high-pitched voice with a lot of infliction and crazy in it.

(This is based on Harley from "Batman: Assualt on Arkham" and the Animated Series -- She's a major background character in Robin: the Series)