Guest Stars Mark Hamill voices The Joker Liane Schirmer voices Officer Renee Montoya Richard Moll voices Twoface Arleen Sorkin voices Harley Quinn Diane Pershing voices Poison Ivy Aron Kincaid voices Killer Croc George Dzundza voices Ventriloquist / Scarface Roddy McDowall voices Mad Hatter Stephanie Zimbalist voices Janet Van Dorn Uncredited Mark Hamill voices Waiter George Dzundza voices Judge