See You There

Synopsis
Mordecai jinxes Rigby, punching him every time he speaks. Rigby must then figure out how to un-jinx himself without talking in the presence of Mordecai. When he cannot get anyone to help him undo the jinx (by chanting his name three times), Rigby performs a forbidden "un-jinxing" ritual: he walks into a bathroom, prints his name onto a mirror, and then chants his name three times. But instead, Rigby mistakenly releases a demonic clone of himself, named Ybgir. The demon Ybgir terrorizes the park, turning almost everyone into demons. This leaves Mordecai and Rigby to try and undo the ritual to send Ybgir back to the mirror, and turn everyone back to normal.

Plot
Mordecai and Rigby are lounging about on the golf cart, but start to clean it when they see Benson coming. Benson tells them that Muscle Man is throwing a costume birthday party for High Five Ghost, but Mordecai and Rigby aren't invited. Mordecai and Rigby go to Mucle Man and joke saying when they should come to the party, but Muscle Man exclaims "Never!" because they're exclusively not invited.

In Mordecai and Rigby's room, Mordecai and Rigby try to figure out why MM didn't invite them to HFG's party. They start reminiscing of this morning, with Muscle Man laughing because Rigby was choking. Wwhen Mordecai does the heimlich on Rigby, stuff flies out of Rigby's mouth and into Muscle Man's soda, splashing it all over MM's face, causing him to go into a rage. When Rigby brings him another soda, he accidentally splashes it in Muscle Man's face, making him even more angry. Back to the present, Mordecai and Rigby give the video game system to Muscle Man and High Five Ghost to try to make amends, but unfortunately for the duo, they're still not invited

Mordecai and Rigby decide to use reverse psychology, but Muscle Man still doesn't buy it. They apologize again, but Muscle Man rudely tells them to get lost, saying he has no idea what they are talking about. That night, they decide to just crash the party, but the bouncer doesn't let them through. Then High Five Ghost's brother, Low Five Ghost suddenly appears outside the tent where the party is being held, and turns them into ghosts upon their request so they can get into the party.

They meet up with Bensons, Skips, Pops, and High Five Ghost. Mordecai and Rigby explain to High Five Ghost that his brother turned Mordecai and Rigby into ghosts so they could crash the party. High Five claims this is bad because if the duo don't change back to normal soon, they'll be ghosts forever. HFG tells LFG to turn them back to normal, but LFG doesn't know how to, but their dad might. HFG and LFG's father tells Mordecai and Rigby that they have to scare somebody in order to return to normal, so they decide to scare Muscle Man, since he doesn't know they're at the party (or so they think).

When MM goes into the bathroom, Mordecai and Rigby jump out and spook him. He goes into a heart attack, and Mordecai and Rigby yell for a doctor. HFG's dad tries to revive MM, but it is (supposedly) too late. Muscle Man then wakes saying that it was all an elaborate prank because the soda incident from earlier. Mordecai and Rigby cannot beleive Muscle Man did all this just because they splashed soda in his face.

Then Muscle Man starts choking from laughing too hard. Mordecai (unwillingly) gives him the heimlich maneuver and Muscle Man finally thanks Mordecai for saving his life. He then throws a tape into the tape deck. MM then (uncharacteristically) apologizes to Mordecai and Rigby for the whole prank, and gives them their game system back, but Mordecai notices that it's just a papier-mâché. Muscle Man says that he sold the real game system to a pawnshop as part of the prank, making them even more angry. Muslce Man then whips out the real game system, saying "Gotcha, dudes".