Death Punchies

Synopsis
Tired of Mordecai always beating him at punchies and getting his way, Rigby decides to learn the martial art of "Death Kwon Do". He steals the instructions for the "Death Punch" and learns it, so Rigby decides to try out the move on unsuspecting people as he prepares for his revenge against Mordecai. Later, when Mordecai learns of Rigby's plan, he also decides to steal some Death Kwon Do moves in order to stop him.

Plot
Mordecai and Rigby are about to play a video game, Dig Champs. Rigby claims it looks just like the cover (which it obviously doesn't). Rigby said they should stretch their 'hammies' to warm up. However, Mordecai started it beforehand. He picked player 1, much to the dismay of Rigby, who hates being player one due to the pickaxe he gets. Mordecai said both weapons are identical in power. Rigby still declines, with Mordecai accepting to play punchies to see who gets to be it. Mordecai wins, as always, as Rigby said that he is sick and tired of punchies. A flashback shows that Rigby has been beaten by Muscle Man, Pops, and even Skips, who made Rigby seriously injured by damaging one of his buttcheeks.

Rigby overreacts and trashes Mordecai's room. He finds an ad on a phone book for a martial arts class. Despite the class being for self-defense, all Rigby wants to use the moves for is for revenge against Mordecai, which the sensei does not appreciate. He saw the death punch and wanted to use it, but the sensei said he is not pure of heart. Rigby said that the sensei is not pure of heart with his 'crappy' mullet. The sensei gets irate and turns his back, claiming when he counts to three, Rigby will 'be toast'. However, Rigby steals the death punch from the book and learns to use it.

Rigby then conquers the park with his new punch and makes the inhabitants his slaves, also getting revenge on the ones who beat him, causing Mordecai to stop him and learn another Death Kwon Do move called the Death Block. He use the Death Block against Rigby’s Death Punch. However, their fight gets them trapped inside a lava pit. Rigby will not stop fighting until he beats Mordecai at punchies. Mordecai has a flashback at how many times he beat Rigby at punchies. In order to save themselves, Mordecai pretends that Rigby beat him, falling onto the ground and "moaning" in pain.

Rigby stops punching, but now they are being surrounded by lava and are going to die. Mordecai has two moves that can get himself and Rigby out of the lava pit, the Death Dump and Death Jump. The Death Jump is chosen and and they make it out of the lava pit. Back at the house, he lets Rigby be player 1 in the video game they were playing earlier, Dig Champs. When Rigby loses on the first round in the first few seconds, he wants to be player 2 now as he did not know the snails in the game were bad.