Anonymous, 3 letters
Faceless person, 3 letters
Fox Mulder's informant, 3 letters
Game show mystery guest, 3 letters
George F. Kennan's pseudonym, 3 letters
Guy of unknown identity, 3 letters
Man of mystery, 3 letters
Man of unknown identity, 3 letters
Mysterious fellow, 3 letters
Mysterious guy, 3 letters
Mysterious man, 3 letters
Mystery man, 3 letters
Character voiced by Estelle Harris in Toy Story 2, 10 letters