Pitch was a demon from experiment 521, Santa Claus, who was sent to Earth to destroy the spirit of Christmas by tempting a little Mexican girl named Lupita.
In the episode's final host segment, Pitch (now played by Paul Chaplin) visited Deep 13, where he impressed Dr. Forrester and TV's Frank with his plans to "engulf the world in darkness" after lying low for the holiday season. Santa (now played by Kevin Murphy) then showed up itching for a fight with Pitch, at which point Frank pushed the button.
Pitch appeared again in the host segments of experiment 818, Devil Doll, trying to make an honest living by selling "Devil Dolls" door-to-door (or some approximation thereof that accounts for his presence on a wayward satellite). Mike walked in on Crow making a deal with the devil ("A devil, actually; name's Pitch!") and demands that he leave. Pitch leaves his card and invites Crow to call him back when Mike isn't around.
Later in Devil Doll, Pitch returns, teaching Crow the art of soul transference. Servo's soul proves remarkably easy to transfer into a wooden mockup of himself, then later into a toaster strudel with killer gams.
Pitch would have a brief cameo when Mike decided to do an Urkel impression in episode San Francisco International. His quarrel with Santa was apparently resolved, as the two laughed heartily together.