Captain Clown
From Multiversal Omnipedia
Captain Clown appeared to simply be an unusually tall man in clown makeup wearing a sea captain's uniform and hat. But the silent, eternally-smiling Captain Clown was actually a powerful robot used by the Joker to pilot his trash barge/submarine during his scheme to poison Gotham City with insanity-inducing laughing gas. Captain Clown was destroyed by Batman when he knocked the robot into a crushing machine in a junkyard, which mashed Captain Clown into a small metal cube.