Mr. Heyman is George Costanza and Jerry Seinfeld's high school gym teacher. He used to tease George by calling him "Can't stand ya" (a play on "Costanza"). Mr. Heyman was also responsible for having the jocks give George 'wedgies', and occasionally 'atomic wedgies', in which the underwear was successfully pulled up over George's head. George describes Mr. Heyman as having "teeth like baked beans".
Eventually, George reports Mr. Heyman and he gets fired, leading to him becoming a homeless bum. One of his few prized possessions is the book Tropic of Cancer, a library book that Jerry had borrowed in 1971, which Mr. Heyman had stolen from George before losing his job.