Billy Turner

Billy Turner is an unseen character who is a student at South Park Elementary. He is mentioned in the episode "Tsst", as a victim of one of Cartman's pranks. It is not known which grade he's in, but since he is referenced as "little Billy Turner" by Mr. Mackey it is assumed that he is younger than Cartman and below 4th grade. It is not known if he's related to Heidi or Sally Turner.

According to the backstory in "Tsst", Cartman handcuffed Billy's ankle to a flagpole and then gave him a hacksaw. Cartman then told him he had poisoned his lunch milk, and that the only way he could get to the antidote in time would be to saw through his leg. Following this incident, Mr. Mackey mentions that Billy is now being treated at the hospital.