Before Don Rickles, "Fat Jack" was the reigning insult comic. His mumbling asides were also a trademark, and if you wondered what stand-up comic David Letterman was referencing with the "palm to the stomach" pose, it was Jack. Given a cartoon tribute ("the Illegal Eagle" on Beany & Cecil") Leonard also got to star in his own feature, "The Fat Spy" in 1966. Jack died in 1973.