A mid-1990s cartoon based on the infamous Mutant League Football and Mutant League Hockey games by Electronic Arts depicting monsters playing pro sports.
An earthquake at a football stadium reveals a cache of illegally dumped toxic waste which mutates all the spectators into half-human abominations. Soon a pro sports league springs up around the mutants, and rather than make the big bucks, rookie athlete Bones Justice decides to play for his dad's team, the last-place Midway Monsters.
As there were games based on two different sports but featuring a lot of the same characters, the show ran with it by having all the teams competing in multiple sports (though still mostly football), as well as events like monster truck races and wrestling matches. Also keeping in the spirit of the games it was common for players to lose body parts in the course of the games. To keep from killing off the entire cast within three episodes, a device called "the rujvenator" was introduced that could heal practically any injury by bathing the injured mutants in certain chemical mixtures.
- Affirmative Action Girl: The second season introduced us to Thrasher Malone, the show's first female mutant.
- Broken Aesop: In one episode, evil mutants try to trick some adolescent fans into jumping into toxic waste to mutate themselves and be more like their idols in the League. The kids hesitate because "norms can't mutate". The very existence of the Mutant League is proof that isn't true. Everyone in it—from the players, refs, coaches, team owners, play-by-play guy and various mutants who had nothing to do with the League—were ordinary humans once upon a time. Trying to mutate yourself wouldn't be an easy or smart thing to do, sure. But obviously it can be done. Almost ends up being an example of Do Not Do This Cool Thing.
- Catchphrase: Two, spoken by Bob Babble: "UN-BEE-LEEEV-able!" and "OOOOH! That's Gotta Hurt!"
- Christmas Episode: Same thing as A Christmas Carol, but no ghosts.
- Corrupt Corporate Executive: Commissioner Zalgor Prig constantly tries to kill Bones for not agreeing to play for his team, the Slaycity Slayers.
- Dented Iron: The Monsters' coach is a former player who suffers from a degenerative disease that prevents the rejuvenator from healing injuries fully, he is now left a wreck as all of the injuries he sustained have caught up to him. One episode had the Monsters' picking up a rookie player who turned out to have the same disease, they convince him to switch to coaching while he still has his health.
- Disappeared Dad: Bones' father mysteriously disappeared, and a subplot that never really went anywhere was Bones' quest to find him.
- Everyone Calls Him "Barkeep": Zalgor's main thug is named Thug.
- Good Thing You Can Heal: Although players' arms, legs and heads were frequently knocked off, they could usually come out good as new by bathing in a machine called the rejuvenator. As a couple episodes showed, though, there were things it couldn't fix.
- Merchandise-Driven: There was an almost-unknown line of action figures released based on the show. Had there been a third game in the series, GamePro magazine implied it probably would've been based on the show rather than the games already in existence.
- Pokémon Speak: Moe and Spewter. Of course, they are so dumb that all Moe can say is "Eat dirt," and all Spewter can say is "Dead meat."
- Red Eyes, Take Warning: Bones's eyes glow red right through his shades when he's about to lose his cool on some poor dumb bad guy.
- Retcon: During the first season players would often be said to spending weeks in the rujvenator recovering from their injuries. Seeming to realize a sports league couldn't operate with its players out for that long after every single game, by the second season spending a day in the rujvenator is considered a long enough time.
- Tastes Like Chicken: One episode has some mutants stranded in a blizzard long enough for some of them to consider eating Razor to survive but Kang convinces them to settle for his tail. When this is referenced in a later episode, one of them says it tasted like chicken.
- That's Gotta Hurt: Often shouted out by Bob Babble whenever a player gets injured.
- Toxic Waste Can Do Anything: The premise of the show is that an earthquake ruptures the turf of a sports stadium, venting toxic gases from long-buried industrial waste. The athletes get dosed with this gas, which mutates them into ugly but superhuman creatures that can suffer horrific damage without dying or being convalescent more than a few hours.
- Trademark Favorite Food: Zalgor's is live spiders.
- True Companions: The Midway Monsters steadily come together as a team, mostly thanks to Bones' philosophical encouragement and the occasional Aesop. They're very quick to close ranks whenever any outside force, usually Zalgor, threatens their friends.
- Vocal Dissonance: Bob Babble, the game commentator, who can describe the events of the games the teams play, all the time that his voice is always high-pitched and sounds like the vocal screams of game commentators when they cheer. Mostly the best part is that whenever one player gets injured in a gross way, Bob would often shout out his famous Catchphrase: "OOOOH! That's Gotta Hurt!"
- With My Hands Tied: Discussed and parodied in the Season 2 episode "Enter the Skeletoid", when Razor Kidd tells the strong badass, "I can beat you with one hand tied behind my back!" Of course, the strong guy rips off Razor's arm as a literal response, and the latter snaps back, "Hey! I said tied!" Razor even tries to kick the strong one, who quickly rips off his leg as well!
- Your Head A-Splode: The unfortunate side effect of a machine in one episode that makes players super-strong. Not that it's worse than anything else that happens to the mutants, mind.