Although he elected to have the surgery after thinking it over, Steve starts to have second thoughts after meeting Billy, but is knocked out before he can get away. Due to Stan's smashing of the building with a wrecking crane, he faces being dropped from the remains of the building until he is saved by Stan. As the police approach, Dr. Kalgary instructs Billy to fly away. But as two large metal wings sprout from his back, he drops backwards from the weight onto the floor.
Billy is listed as a possible owner of the mineral rights under the Smith property in "Mine Struggle".
Billy, while a senior at Pearl Bailey High School, only gets to play Jr. varsity football in "Mean Francine".
Billy receives a new tongue for Christmas and can now speak faster in "Salute Your Sllort". He helps Steve and his friends attempt to find a real killer after their friend Sllort is blamed. While working in the police crime lab, Billy discovers that the body is actually the one the boys believe is the killer, and that Sllort is actually a murderous troll.
Billy is voiced by Kevin Michael Richardson.
- "Mine Struggle"
- "Roger's Baby"
- "Family Plan"
- "The Never-Ending Stories"
- "Mean Francine"
- "Persona Assistant"
- "The Future is Borax"
- "The Hall Monitor and the Lunch Lady"
- "Eight Fires"
- "The Hand that Rocks the Rogu"
- "American Data?"
- "Salute Your Sllort"
- "The Old Country"
- "The Last Ride of the Dodge City Rambler"