John Kassir (born 24 October 1957) is an American actor, voice actor and comedian. He is best known as the voice of the Crypt-Keeper in Tales from the Crypt as well as the second voice of Buster Bunny.
When Animaniacs was cast, Charlie Adler was not happy that minor voice actors such as Frank Welker and Rob Paulsen were cast and he was not, so he left. John took over the role of Buster for the rest of the season. Charlie returned to voice Buster for an unproduced Tiny Toons video game. John also voiced Buster for the video game The Great Beanstalk.