Billy first appears with Jerry when they were moving in to Charley's neighbornhood, helping Jerry into grabbing a coffin.
He is later seen protecting and hiding Jerry from the police, saying that Jerry is not a vampire as Charley had said, which obviously worked
When the police leave, Billy watches Charley from his house and smiles to him, making Charley run away from the house.
He appears when Charley and his friends visit their house, Charley tries to show that Jerry is a vampire. Billy is supicious of this, but Jerry accepts the challange, Jerry drinks holy water nothing happens to him, Charley implies that the water was not blessed and asks if Jerry can grab a crucifix. Peter becomes frustated and makes Charley and his friends go out, except him.
Peter uses a mirror and becomes scared when he realized that Jerry has no reflection, Peter runs away from the house in fear.
Billy makes a minor appearance in the Club Rad scene, he is seen inside of the car with Jerry, Evil Ed and Amy. He is last seen near the ending, where Charley and Peter broke into their house for a final showdown, Billy protects Jerry from Charley's crucifix and knocks him out. In his most notably largest role in the film, Peter shoots him point blank, without any effect, he finally shoots him in the face. Billy eventually returns as zombie-like figure, Charley and Peter grabbed a giant wooden stake-like object and impaled him in the chest, causing him to melt into green goo and sand and leaving only his skeleton to shatter into pieces.
- It is not known what Billy actually is. He is not a vampire (As evidenced by the fact that he is perfectly capable of being out in the sunlight), but possesses superhuman strength and survived gunshots. It has been theorized that:
- Billy might be a half-vampire.
- A undead golem created by Jerry.
- A ghoul or a demon.
- A zombie, presumably a revenant.