This team is composed of villainous characters. With the exception of Mumbly and the Dalton Brothers, all of the members are original characters, many of whom are based on various characters that appeared in cartoons and comics prior to Laff-A-Lympics, largely since Hanna-Barbera did not have a large regular stable of villain characters. Originally, Muttley and Dick Dastardly were planned as the leaders of the Really Rottens; however, they could not appear on the show due to those characters being co-owned by Heatter-Quigley Productions. In their place, Hanna-Barbera used the existing character Mumbly and created the new character Dread Baron. Prior to Laff-A-Lympics, Mumbly was a heroic detective based on Lt. Colombo rather than a villain on his original show. Following the character's revision as the villainous team leader, he remained a villain in Yogi Bear and the Magical Flight of the Spruce Goose, which was also Dread Baron's only other role. The Dalton Brothers appeared in 1950s and 1960s shorts (including the 1958 short Sheriff Huckleberry Hound, which featured appearances by Dinky, Dirty, and Dastardly Dalton, as well as their other brothers Dangerous, Detestable, Desperate, and Despicable). However, they were given new character designs for the Laff-A-Lympics series. After Laff-A-Lympics, Dinky reappears in The Good, the Bad, and Huckleberry Hound with brothers Stinky (who bears a resemblance to Dastardly from Laff-A-Lympics), Finky, and Pinky.
The Rottens seek revenge on The Scooby Doobies and The Yogi Yahooies in all the episodes.
Much like their intended leader Dick Dastardly, the team had no qualms about cheating, and also much like him, their cheating frequently backfired and aided their opponents instead, when it wasn't exposed outright. That said, like the Wacky Races, which activity was cheating and which was just using the characters' abilities was a hard line to draw. Generally speaking, the divider seemed to be that aiding one's self was alright, while sabotaging your opponents was bad. Very much unlike Dastardly however, the Really Rottens actually pulled out a few victories. In a tie-in comic published by Marvel, The Dread Baron and Dick Dastardly were revealed to be twin brothers. Later, Hanna-Barbera's legal department discovered that Dastardly and Muttley had been usable all along. Other characters dropped from the show for legal reasons were Josie of Josie and The Pussycats (owned by Archie Comics) and Jeannie the Genie from the animated version of I Dream Of Jeannie, though her apprentice Baboo was able to appear.
Laff-A-Lympics was parodied on Cartoon Network's Robot Chicken, mashed up with the feature film Munich. In it, the Really Rottens stage a nighttime attack on their rivals with weapons and bombs, killing some (who still manage to die in funny cartoony ways, like Scrappy-Doo's 'Puppy Power!' cry and pose finally being his undoing). Seeking revenge, Scooby-Doo and the heroic characters hunt the Really Rottens down ala the Israeli Mossad hunting the Munich terrorists, although much less competently. The Great Fondoo pleads for his life, stating that he was never a 'real' Hanna-Barbera villain, lampshading the original characters used for the Rottens. At the end, Scooby expresses regret for his violent actions, before being distracted by food and chowing down.
|Dread Baron||Bears a strong resemblance to Dick Dastardly and the Red Max|
|Dinky Dalton||Giant villainous cowboy brother whose Stetson obscures his eyes|
|Dirty Dalton||Short villainous cowboy brother with moustache|
|Dastardly Dalton||Short villainous cowboy brother with blond hair|
|Mr. Creepley||Patriarch of villainous monster family based on The Gruesomes and Mr. & Mrs. J. Evil Scientist|
|Mrs. Creepley||Matriarch of villainous monster family based on The Gruesomes and Mr. & Mrs. J. Evil Scientist|
|Junior Creepley||Member of villainous monster family based on The Gruesomes and Mr. & Mrs. J. Evil Scientist|
|Orful Octopus||Pet of the Creepleys;
Villainous version of Squiddly Diddly and Occy the Octopus (pet of The Gruesomes)
|The Great Fondoo||Evil magician whose tricks and spells never work as intended and always backfired;
Similar to Abner K. Dabra from the 1963 book, Yogi Bear and the Cranky Magician
|Magic Rabbit||Pet of the Great Fondoo;
Bears a resemblance to the White Rabbit from Alice in Wonderland (or What's a Nice Kid Like You Doing in a Place Like This?)
|Daisy Mayhem||Mean-spirited hillbilly with split ends in her hair and bare feet;
Bears a strong resemblance to the Li'l Abner character Moonbeam McSwine
|Sooey||Daisy Mayhem's patch-eyed pig|
- Event #18 in season 2
- Event #22 in season 2
- Event #24 in season 2 (the final event. All teams tied and won trophies together)