John Wayne Gacy Jr. was a clown.
John Wayne Gacy Jr. ( March 17 , 1942 -- May 10 , 1994 ) was an American serial killer and rapist . Gacy became known as the `` Killer Clown '' because of his charitable services at fundraising events , parades , and children 's parties where he would dress as `` Pogo the Clown '' , a character he devised himself .