"Mordeby and Rigbecai" is the seventeenth episode in Season 8 (and two hundred and thirty-fourth overall) of Regular Show. It aired on October 14, 2016.
The guys screw around with a teleportation machine.
After their encounter at UMÄK, The Park is flying through space for their next mission. Mordecai and Rigby are doing inventory in the basement when they find a strange machine: a human-sized, metal box connected by tube to another identical box. Rigby walks in and immediately disappears, only to reappear in the second box on the other side. Mordecai and Rigby realize that it's a teleporter. They start fooling around, such as jumping in it, throwing a football through it, and firing a gun so the laser shot comes out the other side and hits a stack of soda cans. However, they soon get in an argument over who's turn it is to use the teleporter, get physical, and teleport at the same time. This results with their butts switching; as evident by Mordecai having Rigby's raccoon tail (and one-cheeked butt), and Rigby having Mordecai's blue jay tail. Just then, Benson walks in to the room, asking what they were doing. Without noticing their switched tails, Benson orders them to rake the leaves outside, closes the basement door, and locks it. Mordecai and Rigby have to get Benson's keys in order to open the door and teleport themselves back to normal.
Muscle Man finds them with their switched tails, and reveals that he was trained as a Teleporter Technician, and that teleporters need to be calibrated before transporting two life forms. He also says that their switched bodies could become worse. Just then, Mordecai's body and arms changes to Rigby's, and Rigby's arms turn into Mordecai's.
Once they obtain Benson's keys, they try to teleport again, but it only makes things worse. This time, Rigby becomes tall and has Mordecai's arms, while Mordecai becomes short, and his body becomes brown like Rigby's. Rigby enjoys his new, tall body, finally beating Mordecai at Punchies, shooting hoops, and running fast from Mordecai, who just wants his body back. Muscle Man catches Rigby, and brings him back to the teleporter room. Once again, Rigby tries to struggle, and all three of them fall in to the teleporter. Muscle man and Mordecai come out normal, but Rigby comes out as a monster-mix between all three of them, with strength, speed, and muscles.
Mordecai and Muscle man set up a basketball hoop trap, catching Rigby and teleporting him back to normal. Rigby admits to getting carried away.
Mordecai then tells Rigby to keep the teleporters before Benson finds them missing with Rigby saying he will be right there. He then tries to dunk a basketball into the hoop but trips over a small rock.
- Even though Mordecai says that "this is real life, those kind of things don't happen in real life", it is ironic as in their reality, many weird things have happened.
- In this episode, Rigby gets revenge on Mordecai for all the times he's hit him by giving him a taste of his own medicine.
- Mordecai remarks on being the one cheeked wonder, which is name Rigby was given in "Death Punchies."
- The whole episode reference the The Fly in 1986, even with Mordecai saying it is a "dumb movie".
- The machine that Hi Five Ghost and Eileen created to change sewage into clean water is actually a reference to industrial wastewater treatment in many countries.
- Muscle Man taking a sacred oath to be a license teleporter technician could be a reference to the Hippocratic Oath which doctors need to take in order to become professional doctors.
- When Rigby is transformed into a monster that is combination of Mordecai, Muscle Man, and himself, starts to talk to himself in fashion similar to Gollum from the Lord of the Rings films.
- The title-card could be a reference to the Ultimate Cartoon Fighting video where both, Mordecai and Rigby combined themselves to fight off Vegeta, but started arguing over which name is better, so Vegeta easily defeats them.
- This is the fifth and last episode to air during the sixth "Regular Show Bomb."