The Haunted Mansion

The Haunted Mansion is the name of the third Halloween-themed shorts from season three episode, Scary Stories of the School. This story was told by Russel

Plot
The episode begins at nighttime, Russel, Rigby, Mordecai, Luigi, and Jacob are walking down the street, where Russel notices a black house. Everyone suggest going in, and they do. After a look around, Luigi decides to leave, only to be stopped by a Masked Murderer, the Masked Murderer slicing Luigi in half, killing Luigi. The lights then turn off, several noises are heard, and when the lights turn back on, Rigby and the Masked Murderer is gone. Rigby is then heard, which reveals that he's in the television. Russel attempts to get Rigby out, but accidentally changes the channel to a sushi cutting channel, the chef cutting up Rigby, killing Rigby. Russel, Mordecai, and Jacob run upstairs, scared, followed by the Masked Murderer. Russel, terrified, hops out the window, supposedly killing Russel. He then snaps Mordecai's neck, killing Mordecai. He then uses a ray gun, and zaps Jacob into a bedroom (Jacob believes the Masked Murderer is Trixie Tang after being zapped in the room) and kills Jacob with acid gas. The Masked Murderer then walks out of the house, when Russel pounces on the Masked Murderer, who finds out that the Masked Murderer is...LESSUR! Russel and Lessur fight, and are both then stabbed by Freddy Kreuger.

At the end, it turns out it was just a made-up story by Russel. Mordecai and Jacob then call it great, and Luigi asks how Russel came up with the story, and Russel then turns out to be Freddy Kreuger in disguise. Everyone screams as Freddy Kreuger rushes towards the screen and says "Happy Halloween", leaving everyone's fate unknown.

Deaths
Everyone dies in unique, gruesome ways:
 * Luigi is sliced in half by the Masked Murderer
 * Rigby was chopped up by a sushi chef after being sucked in the tv
 * Mordecai's neck is snapped by the Masked Murderer
 * Jacob is dissolved by acid gas
 * Russel, whom has revealed to have survived the impact of the window he hopped out, and the Masked Murderer, whom has been revealed to Lessur, are stabbed by Freddy Kreuger