The Master Prank Caller

The Master Prank Caller is a character seen in Regular Show. His first appearance was in "Prank Callers" as an antagonist but became friends with Mordecai and Rigby during the end of the episode prank calling Benson and sending his sofa to the 70s. His present self was revived by Garrett Bobby Ferguson Jr. in "Exit 9B".

Information
The Master Prank Caller is, as his name suggests, the master of prank calls. He can prank anyone at anytime by talking to them on a phone. He is a large 80's style cell phone with human arms and legs. He is later revealed to be a man in cell phone armour, although he most likely is of inhuman origin because he is capable of performing strange feats of magic - just by dialing numbers on himself, he can get anything he wants (limo, 80's clothes, etc.). He can even send prank-callers he pranks to various years in the past. He also (underneath his phone armour) vaguely resembles an alien like ET.

He first appears in "Prank Callers", pranking an old lady on the internet. Mordecai and Rigby decide to be prank-callers like him and try to prank him. However, it goes wrong and they are transported to 1982 by him. They try to return to the present by sending Benson, Pops, and Skips there to help them prank the Master Prank Caller. After a long chase, they stop him and return to the present through a place filled with doors and a specific year is labeled above each. They find the door and go back home. Then he tells Mordecai and Rigby that all he wanted to do was to do prank calls like them and so they become friends and prank call Benson.

List of Prank Calls

 * "Hello?" "Uh, yes, this is Imasure." "Imasure who?" "Imasure glad that I ain't Joe Mama! Oh yeah, you just got pranked by The Master Prank Caller!"
 * "The 1980's called, they want their cell phones back!"
 * "Hello?" "1,2,3, The 70's called, they want their chair back!" (along with Mordecai and Rigby)
 * "Uh, hello?" "The 80's called, they STILL wantcha'!"
 * "Leave us alone!" "Don't you ever hang up!"
 * "Hello?" "Nice ride, but I like mine better!"
 * "Hello?" (Mordecai) Hey, I've got the 50 pizzas here you ordered." "Sounds great! Bring 'em over!" "Uh, you ordered 50 pizzas?" "Yeah, and hot wings. Get here quick, okay? Your mom's, like, totally starvin." "Uh... yeah, I gotta go!"
 * "Uh, this is Stan." "Stan who?" "Uh, Stan Stannmenson." "Your name's Stan Stannmenson? Congratulations, that's the dumbest fake name I've ever heard."
 * "Hello, is this the Pizza Guy or Stan Stannmenson?" "Uh, both!" "I warned you about leaving me alone. Now I'm gonna prank you so hard you both gonna poop a duke. The 1980's called. They want their cell phones back!"
 * "Don't you ever hang up on me!"
 * "Hello?" "This is The Master Prank Caller - " "Uh, hello? Is anybody there?" 'I said this is The Master Prank Caller and -" "Uh, hello, hello?" "I said this is The Master Prank Caller and - WHAT?" "Haha! You just got pranked, ya loser!"

Trivia

 * The guy, Joe Mama, was mentioned in the SpongeBob Squarepants episode "The Sponge Who Can Fly".
 * He is voiced by both Sam Marin and famous actor Tim Curry. Curry has also made a voice appearance on the show as the evil Hot Dog leader in "Meat Your Maker".
 * The Master Prank Caller may have somehow inhabited the 1980s (possibly '82), since he is in a '80s esque cellphone.
 * He has the power to call people with his phone's body.
 * His present self was shown to fight as one of the fallen enemies in "Exit 9B", even though he had befriended Mordecai and Rigby and he never died in "Prank Callers".