Bieberocalypse 3D: The Wally Story is the tenth episode of Season 2, and the twenty-second episode of Regular Show Adventures.
Benson is telling everyone they can get a paid day off if they come up with a good idea to help pay for damages to the park. Mordecai, Rigby and Wally come up with an idea to have a scary movie night in the abandoned and trash covered cemetery, while Muscle Man thinks they should have a sports night. Benson however chooses Mordecai and Rigby's idea over Muscle Man's. The movie Mordecai, Rigby, and Wally get is called Bieberocalypse (3D Director's Cut); then at the movie, about 357 people show up.
In the middle of the movie, Mordecai pushes Rigby over because of him getting scared and he hits the 3D movie projector, knocking the tape out. When Wally puts the tape back in, he puts it in backwards, damages the tape and somehow wakes up the dead who were resting in the cemetery. Using Muscle Man's sports equipment, Skips, Mordecai, Rigby, Wally, Muscle Man, and High-Five Ghost kill all the Justin Bieber zombies, while the customers believe it is part of the movie. One strong zombie whose name was Howard "Hellion" Fightington (1800–1923) comes out after all the others have been defeated. He is killed when Wally rams him with a golf cart, which explodes and burns down the screen. Benson tells the trio that they get the paid day off, and they should do the exact same thing tomorrow. Mordecai then asks if they could have the day off tomorrow (however, Benson does not answer his question).
- Muscle Man
- High-Five Ghost
- Justin Bieber
- Howard "Hellion" Fightington (antagonist)