Dude…Mordecai looks pretty different.
- For "Do Me a Solid", instead of destroying the tape, Rigby originally kept it.
- Margaret was originally not going to wear any clothes like Mordecai, but was changed for obvious reasons.
- In "Mordecai and the Rigbys", there was supposed to be a scene where Mordecai and Rigby ask Benson why there were instruments in the garage. Benson has a flashback when he used to be a hippie where his ex-girlfriend, Veronica, who is also a gumball machine, leaves him for a business man.
◊ - Rigby was originally going to wear a tie.
- In "Skips Strikes", Skips was originally supposed to have a different secret. Which was him being friends with the Magic Elements.
- The last three minutes of the Halloween special "Terror Tales in the Park" had to be redone because CN deemed it too gory and violent for kids. The end result? Rigby getting egged by a giant egg (which actually is still bad, since a later episode revealed that Rigby is deathly allergic to eggs).
- In "Trucker Hall of Fame", the flashback of Muscle Dad telling Muscle Man to take a raincoat with him on his prom was edited because the censors saw Muscle Man's line "Muscle Dad, I don't need no protection from the rain!" as a blatant condom joke (or an endorsement for unprotected sex. Your call).
- Originally, Mordecai and Rigby's mothers were meant to have major roles in an episode. Mordecai's mother was meant to be the typical mom character who was critical to her son; she was a role model of a mother to everyone else, but not in Mordecai's eyes. Meanwhile, Rigby's mom is sweet, loving and protective of her son. Those seemed like really interesting ideas, but for some reason, J.G. Quintel and the others didn't want to make episodes about Mordecai and Rigby's parents, even through Benton Connor kept recommending it to them. Although there's a Thanksgiving special that finally introduces Mordecai and Rigby's parents, they only make a brief appearances and we don't see much of their personality, and "Maxin' and Relaxin'" shows Mordecai's parents again (his mom is embarrassing, but well-meaning and his father is the sane one and a bit of a doormat).
- Much like the first Halloween special, the second one also had to have its ending changed for being too scary and violent, even for Cartoon Network, though the ending that did air (where the tow truck crashes into a tree and everyone comes out as a ghost) didn't seem like much of an improvement in terms of eschewing death references. Here's some storyboard art showing the ending that did get rejected.
- The "lady" the unicorns brought for Mordecai in "The Unicorns Have Got to Go" was originally supposed to be an obviously cross-dressed man in a skimpy bra, panties, fishnet, and heels outfit, but the Cartoon Network censors asked them to replace the man with something less risque (and they did: it was a blonde biker with long hair who kind of looks like Robert Plant from Led Zeppelin).
- Quintel originally intended for the set-up of the show to be about Mordecai and Rigby working at a zoo full of humans and was very set on it. The higher-ups decided against it, thinking they should work in a park instead (which is what it went for in the final), and Quintel thinks it's actually better that they did. However, some elements of the zoo like cages in certain backgrounds can still be found in the pilot
- Rigby was originally going to be named Ricky, but when J.G. Quintel's wife misheard his name as "Rigby", he ended up liking that name better.
- According to Calvin Wong, they wanted Hulk Hogan to voice Muscle Dad.
- In "Skips' Story" originally the Guardians of Eternal Youth were going to laugh at Walks' name choice.
- In "I Like You Hi", Toby Jones and Owen Dennis intended Yuji to be parody of reality TV personalities who think they're famous, but the only reality show they both watched was Sweet Genius (a Food Network cooking competition where chefs come up with bizarre, yet delicious desserts) so Yuji wasn't based on anything.
- There were some jokes in the episode that had some parts removed that changed the context of the joke.
- Yuji's tattoo was originally going to be on his forehead.
- Mark Hamill originally auditioned for Pops but Sam Marin already got the role, so J.G. Quintel had him audition for Skips instead.
- CJ was originally conceived as more of a "difficult woman" type, but writer Kat Morris felt it was misogynistic and rewrote the character to just having some emotional hangups while otherwise being well-adjusted and kind.
- The episode "Skunked" was originally supposed to be about Rigby being a jerk to everyone after getting sprayed by a skunk, all because he thinks everyone hates him for smelling bad. However, even though it got greenlit, it was scrapped last minute. You can view the original storyboard here
