Actor Wally Cox was an American actor and comedian best known for his role as the mild-mannered character Mr. Peepers on the 1950s television series of the same name. He also starred in the 1960s television series The Adventures of Hiram Holliday. His other notable roles include Marlowe in the film version of Raymond Chandler's novel The Long Goodbye and the voice of the cartoon character Underdog. Cox's three-letter crossword solution is COX.