Fun Song Factory/Regular Show

Version 1

 * Thomas (from Thomas & Friends) as Mordecai
 * Larry (from Spongebob Squarepants) as Rigby (Larry and Rigby both have their names ending with a letter "Y")
 * Emily (from Thomas & Friends) as Margaret
 * Rabbit (from Winnie the Pooh) as Benson
 * Gordon (from Thomas & Friends) as Skips
 * Luigi (from Mario) as Pops
 * Pumbaa (from The Lion King) as Muscle Man
 * Patrick (from Spongebob Squarepants) as High Five Ghost
 * Father (from Codename: Kids Next Door) as Ello Gov'nor
 * The Duck (from An American Tail) as Sausages

Version 2

 * Marco Diaz (Star vs. the Forces of Evil) as Mordecai
 * Bolin (The Legend of Korra) as Rigby
 * Mr. Noodman (Sanjay and Craig) as Benson
 * Wasabi (Big Hero 6) as Skips
 * Dipper (Gravity Falls) as Pops
 * Eddy (Ed, Edd 'n' Eddy) as Muscle Man
 * Radicles (OK K.O.!) as High Five Ghost
 * Wendy (Gravity Falls) as Margaret
 * Ling Xiaoyu (Tekken) as CJ
 * Red Action (OK K.O.!) as Eileen
 * Fairies (The Fairly OddParents) as Unicorns

Version 3

 * Dawn (from Pokemon) as Mordecai
 * May (from Pokemon) as Rigby
 * Sandy Cheeks (from SpongeBob SquarePants) as Pops
 * Mr. Krabs (from SpongeBob SquarePants) as Benson
 * Jimmy Neutron (from Jimmy Neutron: Boy Genius) as Skips
 * Jade West (from Victorious) as Margaret
 * Ash Ketchum (from Pokémon) as Muscle Man
 * Brock (from Pokémon) as High Five Ghost
 * Bowser Jr. (from Mario) as Ello Gov'nor