Starring: Mark Hamill, Kevin Conroy, Efrem Zimbalist Jr., Loren Lester, Bob Hastings
Genres: Action, Animated, Crime, Drama, Family, Fantasy, Mystery
Other mistake: Batman's lungs have plot armor; he has all the time to put his mask on even after exposure to the gas, and he reacts to it coughing at first. Nobody else in the episode reacts with a cough. (00:07:55)
Other mistake: At the beginning of the episode, the truck of the "Gotham Globe" delivers to the newsstand a nice bunch of copies of the newspaper, which naturally bears the name..."Gotham News" (00:01:20)
Factual error: Batman is in Japan and tracks down Kyodai Ken by using Caller ID, which returns a seven-digit "555" number. Telephone numbers in Japan have 8 digits.
Christmas With the Joker - S1-E38
Joker: Jingle bells, Batman smells. Robin laid an egg. The Batmobile lost a wheel and the Joker got awaaaaaaaaayyyyy.
Answer: Because he stole a chemical from his lab.
But Batman knew that with it, Clayface could permanently retain his shape and Clayface desperately wanted to be Matt Hagen again. In a sense, Batman stopped Clayface from becoming human.