Dr. Harleen Frances Quinzel, M.D. is perhaps the most well known villain sidekick in the DC comic world. First appearing in Batman: The Animated Series, this vixen is brimming with mischief and a thick New York accent. She becomes the girlfriend of The Joker, frequently referring to him as "Mr. J." Harley also becomes close friends with fellow supervillain Poison Ivy and often has some interesting forays involving Batman. "Aww come on puddin', don't you wanna rev up your Harley?"