When mortal enemies become friends... for no good reason

I'm not sure if there's an official Sonic the Hedgehog chronology, but at some point in the series, Eggman should have been tried, and possibly executed for his cruel and unusual crimes against nature. At least Mega Man's Dr. Wily had to hide behind the Russian pseudonym of named Dr. Cossack for a game to escape suspicion after robo-enslaving the Earth. Meanwhile, Dr. Robotnik gets to swat at fuzzy green balls after temporarily crippling the planet.

Despite his intent to incase all of Sonic's woodland friends within robotic husks, Eggman is apparently invited over to play friendly games of tennis with his archenemy, and possibly enjoy some refreshing Arnold Palmers afterward. The delightful mix of lemonade and iced tea is enough to make anyone forget about multiple attempted genocides.

The great-granddaddy of mascot mash-ups, Mario Kart stunned the world in 1993 by introducing Bowser as a playable character--just a handful of years before he'd fight alongside Mario in Super Mario RPG. And in a slightly shocking move, the normally captive Princess Peach can race alongside him as an equal, which makes her seem especially forgiving of her captor.

After all, Super Mario Kart takes place after Bowser has kidnapped Peach at least three non-consecutive times, so you think there'd at least be a restraining order involved. And despite his continued plotting to murder Mario, he still gets invited back to every new Mario Kart with no explanation. Needless to say, the stakes must be so low in the Mushroom Kingdom that Mario and the gang let Bowser into these off-hour competitions just because they take pity on him and his perpetual failure.

Crash Bandicoot might have only had half a decade of Sony stardom before the Jaxes, Daxters, Ratchets, and Clanks pushed him out of his console home, but one of his best games took the form of a kart racer. That’s a feat made even more impressive when you remember it came out in an era filled with some terrible kart racers. And since Crash's stable of characters was never all that large, like with Mario Kart, the villain once again fills out the roster despite his past transgressions.

In this case, the former bad guy joins in the on the fun for a common good. As one of the few kart racers with an honest-to-goodness story, Crash Team Racing sets it protagonists against Nitros Oxide, an otherworldly being who wants to turn the planet into a parking lot. Neo Cortex's switch from evil to good should be commended, but, as a character, he's a little too mad scientist-y to be trusted.

The Olympics have always been a substitute for war without the need for all of that messy clean-up, bringing together nations with centuries of animosity building up. So it shouldn't be a surprise to see so many heroes and villains paired off in Sega's cartoony take on this centuries-old tradition. And though their universes have never really clashed per se, seeing Sonic and Mario billed in a game alongside each other feels like the all-too-late conclusion of the 16-bit console wars.

Even though the characters exist separately from their marketing, it's strange to see Mario and Sonic paired together when you consider the years of sniping and fierce competition that went on between their respective companies in the ‘90s. Though the fact that Mario's only willing to cooperate with Sonic on smaller-scale titles like these may indicate their pairing isn't entirely mutual. It’s more like Mario is doing a favor for someone that’s down on his luck.

The world of Pac-Man was never meant to make sense, so everything tends to fall apart once you begin to approach it with any hint of logic. The ghostly quartet, enemies of Pac-Man for over thirty years, have origin stories yet to be explained--are they dead Pac-Men? Or simply the last remnants of a world before spherical, yellow creatures evolved and began to eat everything in sight? All we know is they want to destroy the hungry protagonist.

Whatever the case, it seems odd that Pac-Man would drop his typical eat/run response to ghosts for a lukewarm Mario Party knockoff. Though it's possible the lead from all of those keys Pac has eaten over the decades have caused irreparable damage to his brain. Also, unlike party predecessor Pac-Man Fever, this title sadly doesn’t share its name with a 1970s novelty song.

After Dead or Alive made itself known to fighting game fans via its jiggling breast technology, seeing its female cast wind up in an entirely T&A-based experience wasn't all that surprising back in 2003. Still, the high-stakes nature of the Dead or Alive series--not to mention that melodramatic title--makes Xtreme Volleyball and its XBox 360 sequel notably odd, especially for American gamers who aren't used to seeing pervy titles get a wide release.

DoA regulars like Kasumi and Ayane have a feud that goes back to before they were even born, yet the two overlook their complicated past in the name of fan service, just like the rest of the roster. The goofy game casts these female combatants as willing to drop their various agendas for two weeks of sun, sand, gambling, and free gifts. It makes it difficult to take them seriously the next time they square off for some mortal combat.

Unlike Crash Team Racing before them, the recent Sonic kart racers don't burden themselves with a story. At best, you're just asked to race for the sheer joy of racing. That's all well and good, but again we see the issue of bitter rivals dismissing their justifiable anger to burn rubber. The power of burning rubber seems to heal all wounds.

But compared other kart titles, Sega’s own racing entry brings together an astonishing number of antagonists. Sonic and Eggman! Ulala and Pudding! NiGHTS and Reala! Danica Patrick and Alex Kidd! (A lesser-known rivalry, to be sure.) It's easy to question the integrity of these Sega heroes willing to casually shrug off past grievances, but since it’s unlikely you’ll see any new sequels to games like Space Channel 5 and NiGHTS, these characters should be happy to even make an appearance.

Though it may trash all the personal history leading up to the games on this list, you can take a little hope that any differences can be overcome with a few go karts and soccer balls. Have any other favorite nonsensical team-ups in mind? Share it in the comments!

And if you're looking for more, check out 8 ways to tell a boss fight is about to happen and our pick for 8 tired boss fight tropes that need to die.