Marty Nipples is a frequent background character, notable for usually wearing a t-shirt in the style of the command division of Star Trek: The Original Series.
Marty is beaten by Steve Smith to win the spelling bee championship of Pearl Bailey High School in "Spelling Bee My Baby" when he fails to spell "bologna" correctly. When he is called by Principal Lewis, Lewis remarks on his weird name.
He also appears at Steve and his friends' party for the unpopular kids in "The Unincludeds".
Marty is voiced by Mike Barker.