• Absentee Actor: Benson doesn't appear in a handful of episodes.
  • Actor Allusion:
    • Tim Curry literally is a hot dog who gets covered in mustard in "Meat your Maker".
    • While this is more of a Creator Allusion, J.G. Quintel was born in 1982, the year that Mordecai and Rigby travel back to in "Prank Callers". Plus, the title card of Ello Gov'nor (the movie, not the episode) has "©MCMLXXXII" written on it and the World Dishwashing Championship 1982 video in "Peeps".
    • James Hong basically plays Lo Pan during the episode "Fortune Cookie".
  • Bad Export for You and Banned in China: A lot of episodes have either been edited to pieces or banned outright in Cartoon Network stations airing in the United Kingdom, Australia, the Philippines, and Latin America.
    • In Poland, Romania, and Hungary, the episode "The Unicorns Have Got to Go" has been banned for reasons unknown (probably because of gross-out humor).
    • In Russia, the episode "The Real Thomas: An Intern Special" has been banned because its premise about Thomas being a Russian spy was considered offensive as well as Too Soon, given Russia's current invasion of the Ukraine and the beginning of a second Cold War between the United States and Russia, never mind the fact that Russian news outlet RT called the episode "American propaganda", and indeed, the episode is often seen as sharp, biting, South Park-style commentary on current events. In countries such as the UK and Australia, the episode is allowed to air, but a lot of the Russian references have been cut or altered to rename the country Druznia, purportedly so kids wouldn't fear Russia.
  • Casting Gag:
    • Aside from Skips, Mark Hamill also voiced an implied drunk clown - which might be a reference to The Joker, one of Hamill's most famous roles.
    • They also got Hamill to voice a Commissioner Gordon reference in "Temp Check".
  • The Danza: Roger Craig Smith as Frank Smith.
  • Defictionalization: Now you too can be a member of Mordecai and the Ribgys!
  • Descended Creator:
    • The creator, J.G. Quintel, voices Mordecai and High-Five Ghost after Jeff Bennett was replaced.
    • Minty Lewis, the voice of Eileen, started out as a writer/storyboard artist on the show. When she wrote the line about the baby sea turtle eggs from "Do Me a Solid" and pitched it, they knew she was perfect for Eileen.
  • Hey, It's That Voice!:
  • I Knew It!: Many fans had already guessed that Margaret was lying about having a boyfriend in "1000th Chopper Flight Party", well before "Not Great Double Date" debuted and confirmed it.
  • Missing Episode: Any episodes from Season 1 that aren't re-run much can count, most commonly "The Unicorns Have Got to Go".
  • The Other Darrin: Jeff Bennett voiced High-Five Ghost in his first two appearances instead of Quintel. The only explanation for the actor change (since both Quintel and Bennett are still alive and still doing voice work for the show) is that someone thought Jeff Bennett wasn't right for the role and decided that Quintel would be better (or Bennett missed a rehearsal, Quintel took over, and a mutual agreement was made that Quintel take over for Bennett).
    • On the Thanksgiving episode, Jennifer Hale and Alastair Duncan voiced Mordecai's mom and dad. On the first episode that focused on them ("Maxin' and Relaxin'"), Hale and Duncan were replaced by Katey Sagal and Ed Begley, Jr.
  • Name's the Same: Thomas is the name of both the park's billy-goat intern (who turns out o be a Russian/Druznik spy) and Death's son. Rigby even says so on the episode where Mordecai and C.J. have to babysit Death's son Thomas and C.J. says, "Isn't he, like, in college?" before Mordecai corrects her.
  • Talking to Himself: J.G. Quintel voices both Mordecai and High-Five Ghost, and Sam Marin voices Benson, Pops and Muscle Man. Both they and Mark Hamill (Skips) voice several background characters as well.
  • What Could Have Been
    • 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.
    • In "Skips Strikes", Skip was originally suppose to have a different secret. Which was him being friends with the Magic Elements.