A character from Calvin's imagination, Tracer Bullet first appeared in the story where Hobbes gives Calvin a haircut. (The story begins on page 123 of Something Under the Bed is Drooling.) Bullet, drawn as Calvin in a trenchcoat and a large hat, is a private eye. His stories are always drawn in reverse: a lot of black with white lines. Watterson called it a spoof on the cliches of the film noir genre.