Robert Englund was once roommates with Mark Hamill who is famous for voicing The Joker in Batman The Animated Series and other DCAU material or video games.
Frrank Gorshin best known by the public for his role as the Riddler on the television series Batman (1966) and the movie. Passed away 4 days before this episode premiered.
DEBUT: The Riddler (episode 2.02 "Riddled")