Mr. Heyman is a villain on Seinfeld.
His only appearance was in the episode, The Library. He was George and Jerry's high school gym teacher. George arrives at the library and meets Jerry, who is there because he is said to have never return a book called Tropic of Cancer, and Kramer, and he's very upset, claiming that the homeless man on the steps outside the library is none other than Mr. Heyman, a physical education teacher at Jerry and George's high school. Jerry explains to Kramer how George was responsible for getting Heyman fired. The following day Jerry, George, and Elaine meet at Monk's Cafe, where George tells Elaine the story of why Heyman was really fired. Flashing back to the old high school locker room, Heyman and some of the high school boys give George a wedgie, all the while Heyman deliberately mispronouncing George Costanza's name as "Can't-Stand-Ya". As the flashback ends, George confesses that he complained about the incident, and Heyman was fired the next day. A few days later, George arrives at Jerry's apartment, and confirms that the man outside of the library was indeed Mr. Heyman and proceeds to tell how he just received an "atomic" wedgie from him on the library steps. Jerry then confronts George about the book, which George then remembers losing after the original high school locker incident with Heyman. The episode ends with Heyman, homeless in an alleyway, muttering "Can't-Stand-Ya, Can't-Stand-Ya", with the dilapidated long-lost copy of Tropic of Cancer lying next to him.