-> Written by Benton Connor and Hilary Florido

Muscle Man and High-Five Ghost are planning to prank Mordecai by taping his bed on the ceiling in his room. Pops enters the room when he chasing a balloon. While trying to grab the balloon, he knocks it up towards the bed which touches it causing it to drop on top of him. As the bed starts crushing Pops, he starts crying loud enough for the rest of the park staff to hear him and come to his aid. Muscle Man just stood on the ladder shocked from what his prank has done to Pops. As the park workers all wait outside for Pops be taken to the hospital by paramedics, one of the paramedic tells them that Pops will be alright but he's lucky that the bed didn't kill. When Muscle Man hears this, to runs to Pops and apologies to his and tells him that he will never prank again. After the paramedics drive off, Muscle Man walks away telling the rest of the park staff that he's retiring from pranking for good.

Rigby is joyful that Muscle Man quit pranking until Benson reveals that the park is in danger now that Muscle Man retired from pranking. Benson tells them that the park had a prank war with a rival park, East Pines, lead by their manager, Gene, a talking snack vending machine. They were losing at first, but Muscle Man defeated them by launching a gigantic water balloon at the rival park flooding them. When Mordecai doubts that they will hold a grudge for losing the war, the East Pines restarts the prank war by launching a ton of water balloons at them.

The park staff all meet in Skip's garage where they come up with a plan to prank East Pines. Benson is going to try to get Muscle Man back to pranking, Mordecai and Rigby are planning to take out their bathrooms with jumbo rolls of plastic wrap, and Skips and High-Five Ghost will be using expired bologna and illegal fireworks. Just before they were about to leave, Gene and his workers show up in a van and launches tomatoes at them where they retreat back inside. Skips and High-Five Ghost draws their fire away by running outside leaving Benson, Mordecai, and Rigby to continue their plans.

At Muscle Man's trailer, Muscle Man packs his pranking gear away and sits on his couch acting depressed. Benson enters his trailer, while being barraged by water balloons, and tries to convince Muscle Man out of retirement. Muscle Man tells him that he doesn't do that anymore. Benson ask him if he is willing to let the park get destroyed, but Muscle Man tells him that it's just land and they could replace that anytime but not with a man's life. Benson gives up and leaves his trailer while Muscle Man continues to sit on his couch.

Mordecai and Rigby made to the East Pine bathrooms, they get a call from Benson informing them he could not get Muscle Man back and wants them to resume the plan. As Mordecai and Rigby enters the bathroom and prepares the prank, they get ambushed from behind. Meanwhile somewhere else in East Pines, Skips and High-Five Ghost are hiding in the bushes near a watch tower waiting for Benson's orders. They get a call from Benson telling them he lost Mordecai and Rigby and tells them to start pranking. Skips throws expired bologna all over the place, including some of the East Pines staffs, and High-Five Ghost throws the fireworks inside the building scaring some of workers away. Then they get attacked with tomatoes from other workers. Skips calls Benson, who is hold up in the park house, telling them there's too many of them before being taken out. Benson gets a call of Mordecai and asks him where are they. Mordecai tells him he and Rigby are outside the house, and when Benson sees them they are all tarred and feathered. Benson tells them to get out from there but it's too late and they get ambushed with tomatoes by the rival park. Mordecai and Rigby were hit several times as Benson runs out on the field to rescue them. When Benson reaches them, one of the East Pines worker is driving a truck full of whoopee cushions and when he tips the truck over, all the whoopee cushions deflates creating a huge sonic boom that blows them away along with the trees and parts of the house. They try to run back to the house, but Gene and his workers drive their van in front of them and he throws marbles on the ground making them slip and fall. Gene tells them to say good-bye to their park because when they're done with it they'll have nothing left as more whoopee cushion trucks start destroying more trees. Rigby said they need to get out of here before someone gets hurt or killed. Benson has idea on how to end this so he takes the cart and drives off.

Back at Muscle Man's trailer, Muscle Man still continues to sit on his couch. Benson enters his trailer with Pops who is in wheelchair with bandages on his head and has an arm sling. Pops tries to encourage Muscle Man back to pranking but he still refuses. Muscle Man looks outside his trailer seeing the rival park destroying the park by filling the fountain with tomatoes, toilet papering trees, using planes to drops pies all over the place, and dumping purple drink mix in the park lake. He tells Pops that their prank isn't hurting anyone and that his prank can kill and he's worried that he'll kill again. Pops thinks they have lost, but he is happy that the rival park gave him a "get well" gift. When Pops opens it, a boxing glove pops out and hits Pops in the eye and out of his wheelchair, which makes him cry again. This angers Muscle Man to come out of retirement and he prepares for war.

Back at East Pines park, Gene is in a watch tower watching his men destroy the park on his security monitors. Suddenly he sees most of his men have been quickly taken out and sees Muscle Man's face on all the monitors. A large holographic Muscle Man head appears in front of Gene and demands him to stop the prank war, but Gene refuses. Muscle Man then makes the watch tower fly into space and disassembles it leaving Gene outside in space. Gene starts hurling into an illusion of a two-headed lizard and then hurling into the sun. Gene gets so scared that he promises he will never prank the park again. Muscle Man reveals that whole thing he did was a mirror trick. Muscle Man then makes Gene and his men clean up all the damage they caused to the park, which Gene refused until Muscle Man threatens to bring back mirrors again.

While the East Pines workers clean the park, Benson thanks everyone for their hard work, especially to Muscle Man. Muscle Man said he's never retiring from pranking, he starts swinging his shirt around his head and runs off as High-Five Ghost follows him. Benson starts taking Pops back to the hospital. As they got far away from the others he thanks Pops for faking that boxing glove prank knowing Muscle Man would only prank Gene if he pretended to be hurt.

!!This episode provides examples of:
* AchillesInHisTent: Muscle Man.
* BatmanGambit: In order for Benson to get Muscle Man back into the prank war, he had Pops fake getting hurt from the boxing glove prank and let Muscle Man think that the rival park gave him the gift.
* BigNo: Two. One from Gene when Muscle Man's giant water balloon floods his park and one from Benson when he sees Mordecai and Rigby getting shot with tomatoes.
* CurbStompBattle: Without Muscle Man, the East Pine park nearly destroys the park without suffering much damage from their side.
* DeadlyPrank: The entire prank war and Muscle Man's prank of taping Mordecai's bed to the ceiling that nearly kills Pops.
* DeathFromAbove: To end the first prank war, Muscle Man launches a gigantic water balloon (with "My Mom" on it) that floods the entire rival park.
** RainOfArrows: The East Pines park uses water balloons instead when declaring the prank war.
* EdibleAmmunition: The East Pines park fires tomatoes at the park staff and Skips uses expired bologna to wreck havoc in East Pine park.
* EscalatingWar
* FurryConfusion: see TarredAndFeathered
* MyGodWhatHaveIDone: Muscle Man gets this when his prank almost got Pops killed.
* OneManArmy: After Muscle Man goes back to pranking, he took out all the East Park workers quickly.
* PieInTheFace: The East Pines park uses planes to drop pies all over the park.
* SeriousBusiness: The entire prank war.
* TarredAndFeathered: Mordecai and Rigby are victims of this, though why would Mordecai need to be tarred and feathered when he's a bluejay?
* TemptingFate: When Mordecai doubts that Gene holds a grudge for losing the prank war, cue incoming water balloons.