Guest Stars Clancy Brown voices Lex Luthor William Atherton voices Dr. Destiny / John Dee Mark Hamill voices Solomon Grundy Peri Gilpin voices Volcana / Claire Selton Fairuza Balk voices Penny Dee Mark Rolston voices Firefly / Garfield Lynns Richard McGonagle voices Warden Nicholas Guest voices Luminus / Edward Lytener Nicholas Guest voices Dr. Bill Brooks Uncredited Carl Lumbly voices Inmate Mark Hamill voices The Joker Michael Rosenbaum voices Guard Maria Canals-Barrera voices Cop Richard McGonagle voices Rick Jose Yenque voices Copperhead