Enemy Mine

"Just this once, we work together! Mortal enemies working together for the common good!"

- Dib on teaming up with Zim, Invader Zim, "Bolognius Maximus"

A shorter form of the phrase: The enemy of my enemy is my friend. Another phrase used to describe this is "War makes for strange bedfellows." This results in a scenario where foes must work together to achieve a common goal.

This type of team-up usually starts with the villain coming to the hero's aid, usually saying that a certain threat is a danger to them both, or "No one kills you but me!" when they save the hero from certain doom. After the team-up, the villain will usually let the hero live for now because they were so useful, so everything can return to status quo.

Frequently, if it is a goodie-baddie partnership, the baddie will look for opportunities to pull something that gets them a profit (or, in the case of really bad baddies, allows them to stab the goodie in the back).

Of course, the Status Quo Is God is usually maintained by the end, with the villain having returned to his evil ways after pitching in to defeat the external threat. Ungrateful Bastard. Except when it isn't, and there's creep towards Friendly Enemy status. Can become a Heel Face Revolving Door if it happens more than once.

Sometimes the baddie is more the hero's Worthy Opponent than a villain, and it's a pity to see them go back to their old rivalry in the end because together, they're a nearly unstoppable fighting force. (If they don't go back, it's Fire-Forged Friends.)

A good source of Foe Yay, whether due to the fact that the villain secretly does harbor feelings for the protagonist (a direct example) or simply realizes how boring and/or aimless his life would be without the protagonist. Compare Embarrassing Rescue, Gondor Calls for Aid. See also Enemy Civil War.

See also An Offer You Can't Refuse, Genghis Gambit, and Colliding Criminal Conspiracies. When there's no common enemy per se, it's Go-Karting With Bowser. If the villain saves the day without the hero's help, then Bad Guys Do the Dirty Work. If the villain in question is possessing the hero, but there's a greater threat the two must conquer together, this can result in a Symbiotic Possession. Contrast with We ARE Struggling Together!, where you have putative allies who end up backstabbing and/or infighting with each other.

As might be gathered by this point, this article is unrelated to passive defensive weapons planted by one's foes. Also not related to mines of the underground type; for that, see Underground Level or Minecart Madness.

Finally, this is an opportunity to show the villains as being more competent than they typically are. While they're defeated by the heroes week after week, the bad guys can actually contribute to the defeat of whatever threat they're teaming up with the heroes against.

Obviously, beware spoilers.

Not to be confused with the Dennis Quaid movie/Barry Longyear story Enemy Mine. We also sincerely hope that you did not have a slip of the finger and ended up here instead of at Enemy Mime. For an enemy that is a mine, see Action Bomb, and for a different kind of mine which is filled with enemies, see Dug Too Deep.

Compare Nominal Hero, a character who fights for good even though their intentions are not heroic at all.

Anime & Manga
"James: Looks like everything's back to normal.
 * Subverted in UFO Robo Grendizer. In one of the manga versions, Great Mazinger Big Bad, Emperor of Darkness, offered Kouji Kabuto an alliance to fight the Vegans. It was subverted because Kouji refused the offer and Big Bad King Vega
 * In the anime version of Valkyria Chronicles, Episode 12 has Welkin and Faldio team up with Jaeger and Selvaria to foil a plot to to kidnap Princess Cordelia (and Alicia, who was captured in the process) and use her to BS an impromptu alliance between the Federation and Gallia, which is really a cheap way for Prime Minster Borg to usurp the throne "legally" and force the Imperial forces into a two front war situation, which at best leaves him in control of Gallia with Federation backing and gives the Imperial forces pause, or at worst ensures the Imperials are forced to fight a much bigger enemy on two fronts, with either outcome leaving him at an advantage. Everyone launches obvious objections to Welkin's proposed Enemy Mine until Welkin points out the massive mutual gain they stand to profit from, leading to a brief Imperial-Gallia alliance to foil the plot.
 * In the first two Magical Girl Lyrical Nanoha seasons, Nanoha's determination finally pays off, and her rivals turn on their creator and help her and the Time-Space Admin crew.
 * It's a mixed bag in StrikerS. On the one hand,  On the other hand,
 * In Pokémon, the heroes are forced to work with Team Rocket every once in a while, most often in the movies where the whole world is in danger. It happens the point the trio performs a Lampshade Hanging on it in Movie 8:

Jessie: Which means we're back to being losers."


 * This is the whole plot of the episode "Pikachu Re-Volts". After Jessie and James's Pokemon are controlled and taken by their fellow Team Rocket members, Cassidy and Butch, Ash and company team up with them to get the Pokemon back.
 * The most bizarre version of this has to be the Season 7 episode "The Bicker the Better", where after much squabbling between males and females, Jessie recruits a (slightly reluctant) May into a tag team battle...versus James, who also formed an alliance with Ash, in what Brock calls "the battle of the sexes".
 * And in a first season episode, Ash and the gang even help Team Rocket try to kidnap the Monster of the Week: a Snorlax, which they thought was the one causing the drought in a nearby town.
 * A more traditional example is in the Tag Battle Tournament mini-arc, the finale of the first Diamond and Pearl season. Ash and Paul were randomly picked to compete as a team for a pair of Soothe Bells as the prize. Paul just wanted to get some experience for his team, none of the happiness items for him. The results were not pretty, even though they managed to win.
 * Happens fairly often in Pokémon Special. Sabrina, Koga, and Lt. Surge of Team Rocket aid the protagonists against the Elite Four in the Yellow chapter, while Lorelei of the Elite Four helps the protagonists when Team Rocket invades her hometown.
 * Near the end of Pokémon Diamond and Pearl Adventure, Cyrus and his three top officers . When he was last in power, Cyrus had attempted to destroy the universe.
 * In Yu-Gi-Oh, Yugi and Kaiba are frequently forced to team up against a bigger threat, and it almost always ends with Kaiba walking away muttering about how he is destined to beat Yugi someday.
 * Also, Malik and Bakura's alliance, specifically in the duel against Yami no Malik.
 * Similarly during the formation of the same team in Yu-Gi-Oh the Abridged Series, Marik proclaims, "And the enemy of my friend is also my enemy!" Bakura informs him that's not how it goes.
 * Gundam 00 has the alliance between the Big Three (Union, HRL, AEU) which was formed to defeat the rogue paramilitary organization Celestial Being.
 * In Episode 17, all five sides (Celestial Being, Katharon, the coup d'etat forces, the regular Earth Federation military, and A-Laws) temporarily dispose of their hatreds in a Crowning Moment of Awesome for all sides that involves stopping a potential Ice Age and the slaughter of tens of millions of lives by shooting down the countless falling pieces of the destroyed Africa Orbital Elevator.
 * Later in season 2, the Federation army reluctantly allies itself with bitter enemies Celestial Being and Katharon against the A-Laws and the Innovators.
 * In Death Note, Near and Mello are bona fide enemies, despite being Worthy Opponents. When Kira manages to be a bigger fish to fry than they had expected, they do end up de facto needing to work together, using the only female on their of their teams as a liaison, and pretending viciously that they want nothing to do with each other.
 * Near's pretty clear that he'd have no problem working with Mello, to the point that it could be argued he does want to. Mello's the one who wants nothing to do with Near (besides win against him) and tries to verbally pretend he's not helping. "Near, I have no intention of working with you. However, it wouldn't be right to just take my picture and leave. So, I'll settle my debt." Afterward, he still maintains contact with Lidner but pointedly doesn't dwell on the fact that he knows that Near knows about the contact.
 * Also, at one point the investigation team is forced to temporarily ally with Kira himself, as one of the Death Notes ends up in the hands of the Mafia, something that both sides consider the worst possible scenario.
 * Also in the first arc when the Second Kira first appears L agrees to let Light work with the taskforce  Light finds this fortuitous because then he can keep tabs on both L and the Second Kira.
 * Code Geass has Lelouch and Suzaku teaming up to get rid of the Kyushu invaders.
 * Then a season later they team up again to  It worked.
 * Happened at least thrice in the first season of Corrector Yui, where Yui and War Wolf had to teamwork to save either themselves or others. Also happened in the second season of the anime, with Yui and Dark Magical Girl Corrector Ai.
 * Inspector Zenigata is more than willing to team up with Lupin III whenever it involves taking down a more clearly evil criminal (which is surprisingly often). This is implied to be main reason why he hasn't been fired yet.
 * In Dragon Ball Z, Goku and Vegeta's alliance initially starts when they both team up to fight Frieza, the former to save the Universe, the latter because he wants to avenge his pride by defeating Frieza because he was used by him constantly. He ends up redeeming himself and forming a family with Bulma, though he maintains his rivalry against Goku.
 * And before that, Piccolo joined Goku, and later the rest of the cast to fight against the Saiyans. For viewers who joined the show at the start of the Z series, their past history with one another could easily be missed or forgotten.
 * For a while, Dragonball had a pattern where the main antagonist of the previous arc would team up with Goku against the villain of the current one, earning good guy status in the process. This started with Yamcha (who tries to rob Goku in his first appearance) and continues all the way to Freeza, when Toriyama finally gave us a villain too evil to ever join Goku. Here is a list of some of the former villains who joined Goku, mostly through Enemy Mine Heel Face Turns: Oolong, Yamcha, Puar, Tien, Chao-tzu, Piccolo, Vegeta, Android #16, Android #17 (though he never actually met Goku before leaving off-screen shortly after his turn), Android #18, Dabra (according to anime filler in Other World), Majin Buu, Nuova Shenron (in GT), and Abo and Kado (in the recent special which introduced Table to the world.
 * Actually, he made all his friends by fighting them first, except for Roshi, Krillin and Lunch.
 * And Krillin was his training rival for a while.
 * Near the beginning of the Android Saga, Krillin mentions this pattern when Bulma asks the guys why they don't just find Dr. Gero and stop him from ever creating the Androids. So long as they have a common enemy, Vegeta is less likely to revert to being a full-blown villain.
 * Every time Gun for Hire Katana joins the rest of the Techode pilots in Gad Guard to stop a rogue Gad from destroying everything it touches. Interesting in that half the team (both girls, who met him under different circumstances) don't consider him an enemy. His adorable Morality Pet helps.
 * The Impel Down arc in One Piece has been one big Enemy Mine.
 * Taken Up to Eleven in the Whitebeard War arc.
 * Earlier on, Luffy's crew, the Galley-La company, and the Franky Family, despite having fought in a three-way battle before, team up when they realize that they're facing the same enemy, albeit for different reasons (rescuing Robin, dealing with Iceberg's assassins and preventing Pluton's revival, and saving Franky, respectively). Then again, the Galley-La crew had been fighting the Straw Hats under the mistaken belief that they were responsible for the attempt on Iceberg's life, which they just realized.
 * In Ranma One Half, several Enemy Mine alliances emerge among the various members of the Love Dodecahedron. Shampoo, Ukyō and Kodachi regularly team up against any external threat to Ranma (or a new potential suitor). Ranma himself teams with Ryōga and Mousse against Prince Herb. Ranma and Ryōga do this often enough that they inch into Friendly Enemy territory by the end of the series.
 * And inverted with Ryōga and Mousse in the anime: although they aren't enemies when they initially team up against their common enemy Ranma, by the end of the episode, they work so poorly together that they can't stand each other. The fact that Mousse is far more ruthless than Ryōga, and also has no qualms whatsoever about hurting others to get rid of Ranma -- even Akane Tendō, Ryōga's oblivious crush -- does not help matters.
 * In the Three-Tails filler arc of Naruto, Naruto ends up working with to . The fact that they both have an interest in  and neither wants to see the Akatsuki get the beast helps, too.
 * This is also the reason for the very existence of the shinobi alliance, rival nations working together to stop
 * Even Kyuubi joins in. He even spells it out loud and clearly.
 * In one of the Haruhi Suzumiya short stories, the SOS Brigade has to team up with their perceived rival club the Computer Society, in order to stop the plans of the nefarious Student Council President from evicting the Brigade from their clubroom.
 * Occurs twice in Kenichi the Mightiest Disciple, in Kenichi's last battles against Hermit (a.k.a. ) and Boris Ivankov. Both times, a problem occurred to interrupt the battle, and Kenichi would team up with the person he had been fighting moments ago to resolve it, mostly because one party (Hermit in the first, Kenichi himself in the second) didn't want their opponent to get injured and thus be unable to finish the battle. Naturally, the instant the problem is resolved, both cases have Kenichi and his enemy resume the battle, but Hermit at least would later become a full-time ally (Boris may do so as well in the future, but for now, he's been Put On a Bus).
 * The current ongoing arc has.
 * Sara and the Space Squadron make amends with Mariette and her Gambee pilot brigade (sorry, but it doesn't have a name and both common fan nicknames exceed this wiki's age rating) to defend the Libertad in the end of Soukou no Strain.
 * In the finale of Night Wizard, after spending the entire show chasing the heroes, Bell Zephyr ends up fighting alongside them to defeat the true Big Bad.
 * Pixie Misa does this twice in Mahou Shoujo Pretty Sammy. In the same episode. Misa and Sammy also team up briefly in the second and third OVAs.
 * All the non-Shinryuuji Naga players on Team Japan and Agon in Eyeshield 21. And to a lesser degree, all the non-Hakushuu Dinosaurs players and Gaoh (especially Kid, Hiruma and Banba).
 * At one point in Eureka Seven, Renton and Dominic are forced to work together to save Eureka and Anemone.
 * Two examples from Soul Eater:
 * In order to further her plans, Medusa joins forces with Shibusen and leads a team to infiltrate Baba Yaga castle, the Arachnaphobia base.
 * Werewolf Free and shinigami Death the Kid fight Mosquito together. Neither are happy about the idea.
 * During a match in the individual tournament in Saki, everyone in the table gangs up on Saki, despite one of them being her own team mate.
 * In Fullmetal Alchemist, Envy works briefly with Ed and Ling when they have to get out from Gluttony's stomach.
 * Then he goes One-Winged Angel and tries to kill them...
 * Ed joins forces with
 * In Spriggan, Spetsnaz officer Victor Shutrov (or Stolov, based on the Singaporean English translation) tries to kill Japanese KGB agent Koichi Moroha when he learns of his plan to dominate the world via the Fire Shrine and not on behalf of the USSR, helping Yu somewhat. He's killed later, not being able to stop the renegade agent. Yu and Jean team with two of their enemies near the end of the manga. They consist of Iwao Akatsuki, ex-Trident Corporation commando, and Bo Brantz, ex-Neo Nazi and ninja, to defeat Larry Markson from using the natural energy of Gaia in the South Pole.
 * In Berserk, Guts and Zodd have an AWESOME one of these when they temporarily
 * Even though catching the Kaitou Kid is one of Detective Conan's chief aims, second only to busting up the Black Organization, Conan often ends up working together with Kid to catch bad guys or otherwise avert disaster, especially in his Non Serial Movie appearances. (For that matter, he has occasionally worked together with Black Organization agents against other Black Organization agents, as well.) His TV-special team-up with Lupin III would probably count as well.
 * Kougaiji's team and the Sanzo party do this or help each other out in some way so often in Saiyuki that Kougaiji's "it would be unfair to attack you now but next time we will get the scripture" is met with "yeah, yeah we know"
 * In the final 3 chapters of Psyren, Yoshina Ageha teams up with
 * Anytime Inuyasha and Sesshomaru team up, this happens, though at the end of each scenario Sesshy walks off just a little more of an Anti-Hero than before.
 * Even though catching the Kaitou Kid is one of Detective Conan's chief aims, second only to busting up the Black Organization, Conan often ends up working together with Kid to catch bad guys or otherwise avert disaster, especially in his Non Serial Movie appearances. (For that matter, he has occasionally worked together with Black Organization agents against other Black Organization agents, as well.) His TV-special team-up with Lupin III would probably count as well.
 * Kougaiji's team and the Sanzo party do this or help each other out in some way so often in Saiyuki that Kougaiji's "it would be unfair to attack you now but next time we will get the scripture" is met with "yeah, yeah we know"
 * In the final 3 chapters of Psyren, Yoshina Ageha teams up with
 * Anytime Inuyasha and Sesshomaru team up, this happens, though at the end of each scenario Sesshy walks off just a little more of an Anti-Hero than before.

Card Games

 * Magic the Gathering has a number of scenarios, including current events on Zendikar (with the vampires, elves, humans, Kor, minotaurs, goblins, merfolk and what-have-you uniting against the Eldrazi), and a significant part of the dynamic for the good guys in the Archenemy variant (since they can easily be colors that either do or would hate each other slightly less than they hate the main opponent).
 * Almost all cards in Magic the Gathering are divided into one of five categories, defined by certain characteristics and assigned a colour. The five colours are seen on the back of the cards in a pentangle. The characters and creatures associated with any particular colour are hated by the colours on either of the nearer points, but even they will ally to fight against a colour further away (physically and thematically) from one of them.
 * In Scars of Mirrodin block, the Mirran forces in all five colours were forced to team up against Phyrexia...although the black section was wiped out by the second set, and Phyrexia won.

Comicbooks
"Lex:"Not a single word, Superman. We'll call this the Historic First Team-Up of the forces of "Good" and the forces of "Bad". And I'll take the credit for the win"
 * X-Men: Magneto, always referred to as the Big Bad, is the first person the heroes team up with when someone worse comes along.
 * Particularly in the 90s cartoon, most notably in a season-long storyline in which he and Professor Xavier are stranded together in the Savage Land.
 * The brilliant X-Men graphic novel God Loves, Man Kills was the basis for X2, and thus follows the same plot except that, since the comics have been going on long enough that they didn't feel the need to hammer home his villainy, Magneto doesn't really have a Snap Back the way he does in the movie.
 * And in God Loves, Man Kills II, released to tie in with X2, the X-Men find themselves teaming up with the villain from the original.
 * Magneto has worked with the X-Men in multiple story lines, even becoming the leader in one story arc. This is because, for most writers, Magneto isn't as much a bad guy as he is a Well-Intentioned Extremist.
 * It wasn't just for one arc. In the late 1980s, due to Charles Xavier being absent, a reformed Magneto took over Xavier's School for Gifted Youngsters for something like four years (in real world time). If you were reading X-Men and New Mutants back then, Magneto as the head of the Xavier school felt like a new status quo.
 * Spider-Man's enemies Venom and Carnage hate each other more than they hate him. Any time Carnage pops up, Venom will call a truce with Spider-Man to go wail on Carnage. This most famously occurred in the storyline Maximum Carnage, which was adapted into a Sega Genesis and Super Nintendo game.
 * In the oddly-named "Venom vs Carnage" comic, after Carnage produces a new symbiote, he and Venom decide that, in the end, they hate the new symbiote even more than they hate each other (it's implied in Carnage's case that this is part of symbiote biology). The result? Their only teamup. Venom calls it "Temporary. VERY temporary."
 * Spidey and Doc Ock ended up working together at one point, in order to deal with a new villain (Carlyle) who used Ock's arm technology to build a bank-robbing powersuit. While simply being robbed wouldn't have been enough to put Ock on the side of his mortal enemy, there was also the fact that Carlyle was threatening Ock's former fiancée, known to Spider-Man fans as "Aunt May".
 * Actually, Aunt May being endangered wasn't really a factor in the fight. It didn't do anything except surprise Doc Ock for a moment and lead to a very funny The Rocky Horror Picture Show joke. Spidey came into the fight late as Doc Ock was already going after Caryle for stealing his tech and trying to kill him.
 * To Doc's credit, he DID stop a building from collapsing just long enough to allow the innocent civilians to escape at Spidey's prompting. That did nothing to STOP him from letting the building collapse on Spidey, noting "you are not a civilian".
 * Doc Ock also wasn't happy about the inadvertent team-up, later noting (as he told Spidey the weakness in Caryle's armor), "I am not helping you -- I am hurting him." World of difference.
 * It wasn't even the first time Spidey and Ock teamed up, since they also set aside their differences when Hammerhead kidnapped Aunt May. Spider-Man wanted to rescue Aunt May because she was one of his loved ones (along with the fact that he was Spider-Man after all), while Doc Ock wanted to marry May so he could gain access to a nuclear power plant she had inherited.
 * In Marvel's Secret Invasion mega-event,.
 * He has his own reasons for this:.
 * Actually, it's implied that
 * Cassie and Chucky in Hack Slash Vs. Chucky.
 * This was the driving force behind Watchmen's ending in both the original comic and film adaptation.
 * Though the enemy in each was completely different.
 * In the comic book series Elf Quest, when two elf tribes -- the Wolfriders and the newly-introduced Go-Backs -- join forces to wage war against the trolls of King Guttlekraw, the elves form a grudging alliance with the trolls formerly led by the late King Greymung, who have been enslaved by Guttlekraw, even though Greymung's trolls have been the hated enemies of the Wolfriders ever since betraying them back at the start of the storyline. The Go-Backs, meanwhile, would never have thought of teaming up with trolls of any kind, period... But it's probably only because of this uneasy alliance that Guttlekraw's trolls are defeated.
 * In the 1970s, two issues of The Brave and The Bold featured Batman teaming up with The Joker to solve a crime. In #111, they worked together to solve the mass murder of an upstanding local family, which someone had sloppily tried to pin on the Joker. In the end, it turned out that . In #191, the Penguin is murdered and it looks like the Joker did it. When Batman catches up to him, he proves that he couldn't have done it. It is eventually revealed that.
 * In the Marvel Transformers comic, Ratchet and Megatron teamed in an early episode to bring down Shockwave. Megatron, naturally enough, tried to betray Ratchet, but Ratchet was prepared.
 * Several years later, during the "Space Pirates!" story in the UK comic, the Autobots and Decepticons join forces to repel the Quintessons, who are trying to conquer Cybertron before Quintessa explodes. Ultra Magnus and Soundwave even get a Back-to-Back Badasses moment. At the end, Soundwave briefly considers the idea of a lasting peace, but realizes the two factions have come too far to ever resolve their differences.
 * The Autobots and Decepticons were forced to team up again against the Cybertronian Empire, a faction of hyperevolved Decepticons who had abandoned Cybertron eons ago to create a star-spanning empire of their own. They consider the Autobots and the original Decepticons to be disgusting savages, and eventually returned to destroy their "lesser" brethren.
 * At the end of Final Crisis, Superman is facing the Female Furies and the Justifiers. Who saves him and reverses the Anti-Life Equation? Lex Luthor and Dr. Sivana.

Superman:"Whatever you say, Lex. Whatever you say.""


 * Paperinik New Adventures (Donald Duck's superhero alter ego) is forced to work together with a notorious time pirate known as The Raider early on in order to save a large part of Duckburg from being destroyed. Later on, they actually find themselves in Enemy Mine situations so often that they build up a strange kind of friendship.
 * In Cosmic Odyssey, Darkseid and Highfather team up, recruiting Superman, Batman, and various other DC Universe heroes to prevent the Anti-Life Entity from destroying the entire galaxy. To everyone's great surprise, Darkseid betrays his newfound allies, only to be stopped by Batman's Betrayal Insurance.
 * This was hardly the first or the last time that Darkseid pulled one of these. In Crisis On Infinite Earths, for example, ended up being instrumental in finally defeating the Anti-Monitor (but making it very clear he was only doing it not to help the heroes or anything, but rather to ensure that the Anti-Monitor wouldn't destroy everything).
 * Circumstances have forced Thor to team up with members of his Rogues Gallery, including Loki, the Executioner, and the Enchantress.
 * In the Darkwing Duck comic revival, Steelbeak teams up with Darkwing to stop F.O.W.L. High Command's plan to unleash Duckthulu, because Even Evil Has Standards.
 * , Doctor Doom and Reed Richards have very reluctantly agreed to work together in the Future Foundation. This arrangement was brokered by Reed's genius daughter Valeria who convinced Reed that the FF needed someone as ruthlessly pragmatic as Doom if they were going to save the world. She got Doom on board by.
 * Superman and Lex Luthor are in conflict almost all the time, and loathe each other with a vengeance, but they share a near-fanatical adoration for and protectiveness of their home city of Metropolis. This has caused them to put aside their differences, abandon their other objectives, and team up to take down villains bent on destroying their beloved city more than once.
 * In the final issue of Paul Cornell's Knight And Squire, everyone in the British super-community teams up to take down The Joker. The heroes, the anti-heroes, the Harmless Villains and the killers like Death Dinosaur. He's just that much of a threat.
 * In Archie Comics Sonic the Hedgehog, the Freedom Fighters team up with their enemies against a common threat so often that Sonic's started lampshading it. At different points throughout the series, they've teamed up with Robotnik/Eggman, Snively, their Suppression Squad counterparts, the Destructix, the Dark Legion, Ixis Naugus, and Dr. Finitevus. They usually end up getting backstabbed in these situations, to the point that Sonic's started lampshading that too.
 * More recently, we've had a non-Freedom Fighters examples, as the Anti-Hero Babylon Rogues teamed up with their rivals the Battle Bird Armada to find their ancestral homeland of Babylon Gardens -- ironically, this puts them in opposition to the Freedom Fighters, as the entrance to the Gardens is apparently in their home of New Mobotropolis.
 * Happens on a massive scale in the Farscape comic book arc "The War for the Uncharted Territories", when essentially all the factions in the Uncharted Territories have to put aside their rivalries and join forces in order to stand the slightest chance of defending against conquest by the Kkore, which up until then has been defeating everyone in Curb Stomp Battles.
 * One story-arc in the Captain America comic has Cap teaming up with the Red Skull of all people in order to stop a resurrected Hitler from taking control of the Cosmic Cube. Incidentally, this would lead Cap to being briefly exiled from the United States, since the U.S. government assumed he had turned his back on America by aligning with the Skull.

Fan Works

 * The example from Wild Mass Guessing for The X-Files, suggesting that as soon as the aliens arrive on Earth, they'll promptly be beaten back by every single Monster of the Week, who tend to favor continuing to live on their planet.
 * In Aeon Natum Engel, during the Herald fight, the Migou recall some of their forces so that the NEG Military, with the newly freed-up forces, can assist in defeating the Herald. Humanity doesn't return the favor.
 * One issue of Ultimate Spider-Woman: Change With the Light has petty criminal Blizzard teaming up with Spider-Woman to help her protect the innocent people in danger during an invasion of New York City by an army of Brainwashed and Crazy super villains. Taking inspiration from the Darkwing Duck episode where DW teamed up with Megavolt (see below), Blizzard points out that if New York is destroyed, there'll be nothing left for him to rob.
 * A Dark Knight Over Sin City features Batman and the anti-heroes from Sin City teaming up together and with other criminals in order to achieve their goals.
 * In Hogyoku Ex Machina, Yoruichi is surprised when she finds out that the Vizards fought alongside Soul Society against Aizen in the original timeline, since they have no reason to like them. Ishida suggests it was because of this trope.
 * Villain example: Although  and the Raleka in With Strings Attached aren't exactly mortal enemies, they dislike each other considerably.   are contemptuous of Ketafans in general, and the Raleka hate that the skahs want to use the sacred Vasyn for stupid purposes. However, they work together against the four because the Raleka cannot do certain things without  . We find out later that   were planning to betray the Raleka, but Paul and George inadvertently screwed this up for them.
 * Ponies Make War: In a plan born of desperation to defeat Titan during the Final Battle, the Mane Six end up allying with . As   puts it, they know the latter will probably betray them after they're done with Titan, but they can handle that, and besides, "better the devil you know".
 * Queen of All Oni: When Valmont uses the power of Kaito's mask to steal the Ninja tribe away from Jade, she and Jackie briefly (and reluctantly, in her case) team up to defeat him.
 * Subverted in one of the scenes set in Jade's mindscape -- Hero tries to form an alliance against The Queen with his apparent rival Father, but is rejected.
 * In a similar subversion, the J-Team refuses to ally with Karasu against Drago, as they don't see any good coming from working with a Shadowkhan.

Films -- Animation

 * In Shrek,
 * Though slaying the dragon was never part of the bargain; he just had to recover the princess (normally he'd have to slay the dragon, but this time he just outwits her).
 * Also,
 * In the first Toy Story, Woody and Buzz are initially bitter enemies due to Woody's jealously over Andy's affection, but when the two toys end up separated from the rest of the group, they must work together in order to get back home.
 * This trope is the whole point of Monsters vs. Aliens, though the monsters are pretty good-natured.
 * In the Futurama movie "Bender's Big Score", not only is the Robot Devil providing music at, but they later team up with the robot mafia and evil robotic Santa to take Earth back from the scammer aliens.

Films -- Live Action
"Royce: The enemy of my enemy...
 * This is the whole premise behind Independence Day.
 * The Sci-Fi movie Enemy Mine (1985) (directed by Wolfgang Petersen), starring Dennis Quaid as a human space marine and Louis Gossett Jr. as an alien soldier. In the midst of an interstellar war between their species, both crash-landed their vessels on a desolate planet and must work together to survive. Years later, after the alien soldier gave birth to a baby alien and died from complications, Dennis Quaid's character raises his adoptive alien son and must protect him and himself from human scavengers who use captured aliens as slaves, until they're both finally found and rescued. It is implied that this event helps to end the war.
 * Hell in the Pacific, about an American and a Japanese soldier trapped on an island together, and which inspired the film in the previous entry, natch.
 * In the Pirates of the Caribbean franchise, every character views the others as either enemies or incredibly stupid pawns, but will readily concede to work together when their priorities mesh. These unholy alliances tend to confuse casual viewers, who are convinced (très incorrectly) that the adversarial role Barbossa plays in the first film completely contradicts the compatriot role he plays in the third.
 * Battra and Mothra, mortal enemies of one another, joined forces in order to stop Godzilla in Godzilla and Mothra The Battle For Earth.
 * Mothra convinces her enemy Godzilla and Rodan to stop Ghidorah in Ghidorah the Three Headed Monster
 * In Dick Tracy, Tracy considers this trope when deciding whether to accept The Blank's help in defeating Big Boy. Instead, he finally realizes "The enemy of my enemy is my enemy."
 * In the first Alien vs. Predator film, the humans end up helping the preds kill xenomorphs by bringing them their ancient weapons.
 * Mentioned in Predators when Royce tells Isabelle that he intends to free the captured Predator and use that momentary trust to have him find the predator's ship and escape. Isabelle then adds:

Isabelle: That doesn't make it a friend."

"Linus: We've shaken every tree...
 * The main premise of The League of Extraordinary Gentlemen.
 * In a Played for Laughs moment from The Rocketeer, it's gangsters siding with the police vs. Nazis. They may be crooks, but they're American crooks. And, yes, there's a jetpack involved.
 * This is what prompts the partnership between Wikus and Christopher in District 9.
 * The Matrix Revolutions. Neo and the Machines must work together to destroy Smith before he takes over both the Matrix and the Machine World.
 * The entire point of X 2 X Men United: the X-Men team up with Magneto and Mystique to stop a human villain from killing all mutants.
 * Wolverine and Sabretooth in X Men Origins Wolverine against In Name Only Deadpool.
 * Kind of lampshaded in Ocean's Thirteen, when they decide to include Benedict in their plan:

Rusty: I really wanted to avoid it this time..."


 * Will Smith's character in Enemy of the State pulls an on-the-fly Batman Gambit which ties up two troublesome loose ends by getting them to deal with each other. Through some fast talking and well chosen ambiguous language, he  It does not end well for any of them.
 * In Blade II, Blade teams up with the vampires to fight a subspecies of super-vampires that prey on everyone. The vampires end up betraying Blade two-thirds of the way through the movie. Nomak (the lead super-vamp) points out the trope: "Is the enemy of my enemy my friend? Or just another enemy?"
 * The first half of The Good the Bad And The Ugly is a slowly-escalating buildup of hatred between Blondie and Tuco to the point where they're inches from clawing out each others' eyes. Then Tuco learns the location of a graveyard where gold is hidden, Blondie learns the name on the grave where the gold is buried, and they're forced to work together, later uniting against Angel Eyes after he learns Tuco's half of the secret.
 * Balthazar and Mathayas resort to this in The Scorpion King in order to take down Emperor Memmon.
 * Subverted by Transformers Dark of the Moon. Prime and Megatron teaming up to battle a greater threat is fairly common in Transformers media, but this time.
 * In Once Upon a Texas Train, the retired outlaws and the retired Rangers are forced to combine forces to combat a gang of younger, more ruthless outlaws.
 * Fantastic Four: Rise of the Silver Surfer has the titular team teaming up with Dr. Doom to get the Silver Surfer. Eventually the Fantastic Four team up with the Surfer

Literature

 * Enemy Mine by Barry B. Longyear, the basis for the movie mentioned above.
 * In William King's Warhammer 40000 novel Space Wolf, the Marines chose Ragnar and Strybjorn for Marines when they were fighting each other to the death, and both were mortally wounded. Ragnar's desire for Revenge is kept at bay by the knowledge that the Marines will not let him.
 * And in the Warchild Series, Captain Azarcon, a Space Marine, and Niko, human sympathizer of the alien resistance work together to
 * EE Doc Smith's Skylark series. In The Skylark of Space, the villain DuQuesne agrees to act as one of the party until they return safely to Earth, even though he wants the hero Richard Seaton dead. Ultimately Seaton In Skylark DuQuesne, DuQuesne enlists Seaton's help in fighting an otherwise unstoppable alien menace and ends up, though by this time.
 * The fact that each man at least respects the other's abilities helps.
 * Worldwar (Literature), by Harry Turtledove. Aliens invade in 1942. The Axis are working with the Allies. Another one occurs between the Jews in Europe and the Race. Aliens who never figured out discrimination or Nazi Germany. Played with in the sense that they aren't quite sure who'd be worse for mankind. (The Jews play it both ways,working with the Race or the Germans depending on who's a bigger threat at the time.)
 * In Harry Potter, Narcissa Malfoy
 * The Thrawn Trilogy: Mara Jade sees her having to constantly work with Luke as this trope, especially with that not-so-covert wish to kill him. He doesn't see it the same way, though. At the end of the trilogy, they've become Fire-Forged Friends, and by the New Jedi Order series, they're a married Battle Couple.
 * The Truce At Bakura is this trope personified, with the Imperials forced to work with the Rebels to defeat the evil Ssi-Ruuk.
 * In A Darkness at Sethanon, the Heroic Prince teams up with the former Evil Chancellor to defend a city against the The Horde. Subverted in that they not only fail to defend the city, but manage to blow it up.
 * That isn't really a failure though. They were outnumbered about fifteen to one, and their enemy was using magic. The destruction of the city was to prevent the enemy from taking it and destroy a lot of the enemy along with it. Given the odds, it was a resounding success and achieved its goal perfectly.
 * Until it's revealed at the end that a massive casualty toll was what the Big Bad wanted all along -- Murmandamus, in reality a Pantathian disguised as the legendary moredhel prophet to manipulate the moredhel, was using the escaped life energy to power himself up to be able to activate the Doomsday Device at Sethanon, and it didn't matter to him in the least if the dead were human or moredhel (or troll or goblin).
 * In Honored Enemy, a band of Kingdom raiders allies with a Tsurani patrol in order to survive pursuit from a Moredhel company. The story plays during the war between the Kingdom and the Tsurani and revolves around the tension this causes.
 * In Betrayal At Krondor, the moredhel chieftain Gorath seeks out Prince Arutha to curb another upcoming invasion that he feels would be too costly for his people.
 * The Animorphs only teamed up with their main enemy, Visser Three, twice: to defeat a race of annoying, psycho, tiny-tiny-tiny aliens with a shrink ray and a mass Napoleon Complex, and to escape from a bunch of mutated blue fish-people that want to kill and stuff them for their Derelict Graveyard. On the other hand, Visser One freed them from Visser Three's prison in her very first appearance. Since the Animorphs are guerrilla fighters and Visser One is the main advocate for a stealth invasion (and her host is ), they're not unwilling to accommodate her if it hurts Visser Three's credibility -- but they're not unwilling to use it as an excuse to double-cross her, either...
 * In The Other Wind, the last (so far) in Ursula K. Le Guin's Earthsea series, representatives of four cultures normally at loggerheads - if not outright enmity - have to pool their respective mythological knowledge in order to figure out the truth about an ancient evil.
 * In the Crown of Slaves sub-series of the Honorverse, Victor Cachat and Anton Zilwicki are two intelligence operatives from the warring Star Empire of Manticore and the Republic of Haven (Formerly Peoples Republic of Haven). They team up to investigate Mesan intrigue and how it impacts the war. It's implied this sub series may lead to a Grand Alliance...
 * Really, by now it's evident that The Climactic Conflict will be between the Andermani/Havenites/Manticore/Maya/Beowulf/Torch/others versus the frikkin' huge Solarian League (minus bits like Maya)/Mesa/whatever else we haven't seen yet. It promises to be awesome.
 * As of Mission Of Honor,
 * Tad Williams' Otherland Cyberpunk novel series has a prominent example of this in the fourth book. After Psycho for Hire John Dread usurps control of the Otherland network, Corrupt Corporate Executive Felix Jongleur, who up until now has regarded the heroes as an annoyance (if he was aware of them at all), finds himself on equal footing with them: trapped in the network and unable to use his godlike powers.
 * This is a major part of the plot of all 3 novels in CS Friedman's Coldfire Trilogy trilogy: an immortal vampire and a priest team up to fight mutual enemies.
 * The Hobbit. The dwarves are about to fight a battle with the Lake-men and Wood-elves to determine who will gain Smaug's treasure. Gandalf appears and warns them that an army of goblins and wargs is approaching, and they must join together to fight the evil attackers.
 * In Dragonlance, black robed mages ally themselves with the good guys every now and then, for example to drive off the Dark Queen in Legend of Huma and during the War of the Lance. Dragons of Summer Flame was based around this trope. Also Fistandantilus and the Kingpriest used each other for their own goals.
 * In The Legend of Drizzt Drizzt Do'Urden and Artemis Entreri must team up and fight back to back in an effort to get out of the Underdark at one point.
 * It is briefly mentioned in the Warhammer 40000 novel Grey Knights that the underhive gangs of Volcanis Ultor "buried their enmities for one long night" to do battle with a powerful gang of Chaos followers.
 * Twilight: The Cullens (Vegetarian Vampires) and the Quilettes (Werewolves born to kill vampires), had to work together to destroy an army of newborn vampires that were killing people in general and wanted to kill Bella Swan in particular.
 * Star Wars: While most of the clone troopers went on to serve the empire, the True Mandalorians (a.k.a. the group that nearly destroyed the Galactic Republic 4,000 years ago) fought alongside the rebels to retain their heritage as well as kill those who had betrayed their own kin.
 * Fate of the Jedi: Jedi and the Lost Tribe of the Sith form an alliance (in the titular Allies), to investigate and subdue a feminine Eldritch Abomination named Abeloth. The arrangement doesn't last long, but it does allow Luke's son Ben to pick up a Sith Apprentice Girlfriend...
 * Speaking of Fate of the Jedi, Apocalypse reveals that the Father, the Son, and the Daughter had fought against Abeloth multiple times after she got corrupted. The mere fact that the Son, who is the embodiment of the Dark Side, would ally himself with the Daughter, who is the embodiment of the Light Side, even when they would more often than not fight each other to the death had it not been for the Father's influence would imply that this trope came into play.
 * A Song of Ice and Fire has some interesting ones. Jaime Lannister and Brienne of Tarth are forced to coexist when Catelyn Stark sends Brienne to trade Jaime for Sansa, but though they start out quite hostile, they've actually reached a point of sort-of friendship and mutual respect (and maybe more). A more hostile camaraderie briefly exists between Sandor Clegane and Arya Stark; she still hates him, sure, but when it comes down to it they work well together, and she's probably more like him than she'd like to acknowledge. On a larger scale in A Dance with Dragons
 * Recently reversed in the Star Trek Expanded Universe. In the wake of the Borg invasion, several previously non-aligned minor enemies such as the Tholians join the Typhon Pact in order to leave the Federation and Klingon Empire surrounded by a hostile power. The Tholians, well-known for xenophobia, join for this reason alone.
 * The Dale Brown novel Air Battle Force culminates in  working with Turkmen and American forces against the Russians, which continues into Plan of Attack.
 * Edge of Battle has  reluctantly cooperating after Comandante Veracruz's double-cross, though it doesn't last.
 * Strike Force is centred on an Iranian coup leader and former enemy of Dreamland who now needs their help. The blurb tells you as much!
 * A Pict Song by Rudyard Kipling. "No indeed! We are not strong, But we know Peoples that are..."
 * The White Rose by Glen Cook. In the final battle the Lady -- sorceress leader of the northern empire -- needs the help of the white rose to take down the dominator, her husband and a much better sorcerer. The white rose creates a area where magic cannot be used and therefore is vital to taking down the greatest sorcerer in known history.
 * In Streams of Silver, Drizzt Do'Urden and Artemis Entreri declared a temporary truce in order to join forces against a common enemy. Some time later, in Starless Night, Catti-Brie and Entreri teamed up to rescue Drizzt from the drow, who were holding all three of them captive and who would have eventually executed both Drizzt and Entreri. (Or condemned them to a Fate Worse Than Death.)
 * Artemis Fowl and Holly do this in The Arctic Incident and The Eternity Code -- they are opponents, or at the very least rivals with a sore history, even though they have both saved each others' lives by now. In The Arctic Incident, they cooperate as part of a deal: Artemis uses his above-world influence to investigate a smuggler, while the LEP use their advanced technology to help rescue Fowl Senior. In The Eternity Code, their relationship is more tense as they cooperate to resolve a situation Artemis is partly to blame for. By The Opal Deception, they are friends, and later possibly more than that, though that does not go anywhere.
 * A complicated example occurs in the "Richard Bachman" (actually Stephen King) novel The Regulators. The demon Tak is possessing a young autistic boy, and is somehow using the boy's unique mind to augment and give shape to its supernatural power. Both the boy and the demon are fans of cheap westerns and a Power-Rangers style TV show, both of which the demon uses as inspiration for his means of destroying the town. In the show-within-a-show, the heros team up with their enemy to stop a something from destroying Earth. Tak channels this as the final assault on the protagonists.
 * In Hunger, the second book in the Gone series, Sam and Caine do this to kill Drake, team up against the Gaiaphage, rescue Lana, and heal the wounded kids on both sides.
 * This is how Miles Vorkosigan's parents got together, in Shards of Honor.
 * In Robert E Howard's Conan the Barbarian story "Rogues in The House" after Murilo and Conan have broken into Nabonidus's house to kill him, and find that he is not, after all, the Beast Man, they ally with him to deal with it.
 * In Shattered Sky, the third book in the Star Shards Chronicles trilogy, the good guys team up with to defeat a greater enemy that threatens to destroy the universe.
 * In The Trail of Cthulhu, it's revealed that Professor Shrewsbury and Hastur (presented here as Cthulhu's rival brother) have struck an alliance to keep Cthulhu from waking up.
 * In The Dresden Files series, Harry teams up with Lara Raith multiple times over the course of the series to help them reach mutual goals.
 * In the Codex Alera series, the Canim have Gadara, meaning "trusted enemy". Gadara can often work together, as  eventually do.
 * In The Man From UNCLE novel The Dagger Affair by David McDaniel, UNCLE and THRUSH operatives work together to stop DAGGER, a new organization armed with advanced science. In the end a THRUSH-controlled fighter jet kamikazes the DAGGER base, using sheer momentum to overwhelm its force field. There's a poignant moment where the leader of THRUSH reminds the leader of UNCLE of their former friendship and gives him a copy of Nineteen Eighty-Four. Then he ends the truce ahead of the agreed time, not that anyone expected anything else. We also discover that the full name of THRUSH is the somewhat unwieldy "Technological Hierarchy for the Removal of Undesirables and the Subjugation of Humanity".
 * In the second book of the Mistborn trilogy, Vin finds herself working with an enemy -
 * This happens in The Path to War where Tahniya is soul bound to Zan as punishment; they can't stand each other.
 * Bertie Wooster and team up in Thank You, Jeeves and end up getting along very well, even exchanging invitations to lunch. Bertie notes that he can't be all bad, since he.

Live-Action TV
"G'kar: (...)But I don't have to kill you. I don't have to do anything! And I still get to watch you die! I find this most appealing!
 * The X-Files episode "En Ami". And "Tunguska"/"Terma" as well, although that turned out to be a set-up.
 * This is the plot of Star Trek Voyager, although by the third season the rival crew factions have been forgotten.
 * In a later season of Voyager, in the episode where the Delta Flyer is introduced, B'Elanna Torres learns that the Maquis lost back home. She turns depressed and does dangerous things in the Holodeck with the safety off, and because most of the ship has all but forgotten their initial division between Starfleet and Maquis, they don't know what's wrong with her.
 * When they first re-establish contact with Starfleet, Janeway mentions to Chekotay that she actually had forgotten the implications of the mixed crew after they had been working together for so long.
 * Star Trek in general is all over this trope. The Klingons team up with the Enterprise crew in "Day of the Dove", the Klingons allying with the Romulans against the Federation and then later with the Federation against the Romulans, Voyager teaming with the Borg in "Scorpion", The Alliance of the Alpha Quadrant (and the poor, forgotten Beta Quadrant!) against the Dominion, etc., etc.
 * Star Trek Deep Space Nine: Kira, Damar and Garak all loath each other. Eventually, the fate of Cardassia and the Alpha Quadrant rests on the 3 of putting aside their differences and working together to create a rebellion to overthrow the Dominion control of Cardassia. It even leads to the beginning of Fire-Forged Friends.
 * Star Trek Enterprise, "Dawn," "Storm Front" (Archer fighting alongside Silik)
 * Star Trek the Next Generation, "Darmok". In the midst of the plot, Picard retells similar parts of The Epic of Gilgamesh, highlighting this as Older Than Dirt.
 * Rather famously, the Tamarian for this trope is "Darmok and Jalad at Tanagra."
 * TNG also did it in "The Enemy", where Geordi and a Romulan had to work together.
 * In Buffy the Vampire Slayer Buffy teamed up with Spike to stop Angelus at the end of season 2. With some unusual fallout; because the main time she'd met him had been during this Enemy Mine situation, when Spike returned in season 3, Joyce thought that they were actually allies and let him in. In season four he also teamed up with them a few times for various reasons (once because Giles just paid him to), and by the fifth he ran out of a need for outside excuses and turned into a straight ally.
 * In Twenty Four Season 2, Jack is forced to work with Nina Myers, the woman who killed his wife, in order to find information on the season's terrorist threat. Likewise, in season 6, Jack teams up with the previous season's Big Bad to investigate a corrupt Russian diplomat.
 * The Doctor Who serial Logopolis. Of course, the Master turns on the Doctor, tries to destroy the Universe rather than being unable to rule it, and then kills the Doctor by shaking him off a radio telescope into a parking lot. It isn't the end though, as the moment has been prepared for. Considering how the Master is just about the closest thing the Doctor has to a rival, they've certainly been forced to team up on any number of occasions throughout their history -- usually to stop a catastrophic evil that the Master himself unleashed, and invariably with the Master turning on the Doctor shortly before or after the problem is solved. Of course, the Doctor has been anticipating betrayal all along, and has almost certainly done something clever to come out ahead regardless.
 * Happens again in The End of Time, where
 * Differently, in "The Pandorica Opens",
 * In "A Good Man Goes to War",
 * Babylon 5, "Dust to Dust". Bester teams up with Garibaldi to catch drug smugglers. JMS explicitly stated this was to prevent Villain Decay.
 * Another episode has a scene deliberately written in defiance of the trope, which Straczynski hates. Mortal enemies Londo and G'Kar are trapped in an elevator with a fire outside draining their oxygen. Londo declares that they'll have to work together to escape but G'Kar refuses: he's perfectly fine with dying as long as he gets to see Londo die, too.

Londo: This is insane! We must work together!

G'Kar: ... No. As the humans say: "Up yours, die." *Continues giggling*"

"O'Neill: I've got a better idea, instead of helping you, why don't we sit around and watch you get your ass kicked? That way you'll be dead, and we'll be glad."
 * The irony of this is that, if the Narn surrender treaty didn't include such harsh penalties for G'Kar just killing Londo, he might happily have helped. However, thanks to the excessive measures taken to prevent narns attacking centauri, this was the only way G'Kar would ever get to see Londo die.
 * Further irony is piled on by finally playing the trope straight when Londo's Prophecy Twist kicks in. At that point G'Kar is one of the last two friends Londo has.
 * Galactica 1980, episode "The Return of Starbuck". Often the only episode of the series that some fans of the original Battlestar Galactica Classic will accept as continuity.
 * The new Battlestar Galactica Reimagined has this quite a few times as well, usually involving Cylons and humans co-operating, such as Athena's Heel Face Turn and the rebel Cylon faction seeking Galactica's help against Brother Cavil. However the "enemy of my enemy is my friend" quote is actually used by President Roslin when she teams up with terrorist-turned-radical politician Tom Zarek, after Commander Adama tries to force her resignation.
 * Stargate SG-1 features this a great many times. It seems to be one of the favorite negotiating tactics of the Tau'ri in particular.
 * Ba'al has had to join forces with SG-1 to defeat his master Anubis and the greater threat of the Replicators during the "Reckoning" two-parter. This is not the last time they'd work with him. Initially subverted, as Ba'al asked SG-1 for an alliance and was flat-out rejected by Jack O'Neill.

"Angel: You're afraid of what's coming. Maybe we can help each other. The enemy of my enemy--
 * Special mention just has to go to the two-parter "The Quest", where SG-1, Ba'al, and Ori messiah Adria team up to solve Morgan le Fay's puzzles.
 * There is also an SG-1 episode entitled "Enemy Mine", though it is unrelated to this trope at first. The conclusion is somewhat an example of this trope, as the Colonel overseeing the mine and the Unas definitely considered each other enemies until the compromise where they agreed to work the mine themselves so long as it contributed to killing some Goa'uld. Plus they look a little Enemy Mine Lou Gossetty, what with the scaly skin and labored manner of speaking.
 * The original alliance (the one led by Ra) against Anubis, whose crimes were apparently considered unspeakable, even amongst the System Lords. Think about that.
 * Sokar was banished from the System Lords for much the same reason, and by much the same method.
 * According to Thor in "Fair Game", it is precisely because of the concept of "enemy of my enemy" that the Goa'uld System Lords banded together in the first place. Due to their Always Chaotic Evil nature, however, it takes a serious threat (like the Tau'ri) to convince them to work together for any extended length of time.
 * The "Giant Aliens" (later named Omeyocans by the novel City of the Gods) in the episode "Crystal Skull" quote the full line verbatim to SG-1. In Mayan, no less.
 * Then there's the various times the SGC temporarily allied with Lord Yu. To paraphrase Daniel Jackson, Yu is not to be liked or trusted, only trusted to make a practical decision unhampered by the usual Goa'uld mindset.
 * In Stargate Atlantis, Sheppard and a wraith cooperated to escape custody of Kolya in the episode "Common Ground". This included the wraith feeding on Sheppard to have the strength to fight off their enemies, giving it the opportunity to double-cross our hero. However, he returned all the Life Energy he took (and possibly made up for a few months Sheppard spent in a time-dilation field) and Sheppard made good on his promise to let it go free. The wraith in question, later dubbed "Todd", would become a recurring character, and is notable for being unusually sociable for a Wraith, even joking with the heroes.
 * Taken Up to Eleven in the final battle against the Asurans, where the Earth, Traveller, and Wraith ships fight side by side against the Asuran warships in what is hands down the single most awesome space battle any of the three series has managed (Stargate Universe, being set on a Cool Starship, had a chance to top it before it was cancelled). This is even more impressive given the distinctly quarrelsome nature of the Wraith, thus the battle is a meld of nine factions (7 Hives, Atlantis and the Travellers) rather than 3 as some may think.
 * Certain incarnations of Power Rangers have done this, particularly Power Rangers ZEO. The Big Bad of the moment has brainwashed The Hero and the Sixth Ranger's attempt to save him has failed. It turns out that last year's villains have the technology to send the rest of the team over. They do, just to screw around with the new villains.
 * Likewise, a villain variant of this was completely subverted in Turbo: A Power Rangers Movie. Newly anointed Big Bad Divatox calls decayed villain Rita Repulsa for help, and gets laughed at. Rita's Captain Obvious response is that if she knew how to defeat the Rangers, she would have done it already.
 * Airwolf, "Condemned". String and Caitlin have to work together with some Reds With Rockets to acquire the antidote for a lethal virus. Then stop three nuclear warhead-equipped cruise missiles from hitting the island. Soviets attempt to acquire Airwolf, but don't get very far and stop this before things get hairy between them. The parties depart friends.
 * Firefly does this in the episode "Trash", where the crew joins up on a heist with Saffron, the psychotic seductress who tried to steal their ship a few episodes back. Rather amusingly subverted: Saffron unsurprisingly double-crosses the crew, and the crew.
 * Even Scrubs features this trope when Dr. Cox and Dr. Kelso team up to break the spirit of an overly cheery coworker. However, she outsmarts them and they are back to mutual hate by the end of the episode.
 * Another episode featured Dr. Kelso notice that everyone in the hospital was arguing, so he invokes this by getting everyone to turn against him.
 * Buck, Dr. Crower, Gail, and Ben are all forced to work together in the American Gothic episode "The Beast Within", when Ben's deranged brother takes them all hostage: Dr. Matt's hand is hurt so he has to coach Ben in performing an emergency surgery, while Buck and Gail have to work together to find the lost key to the handcuffs holding them and Caleb prisoner. (The fact this all turns out to be rather subverts the trope.)
 * And at the very end of the series, Merlyn is forced to go to Dr. Peele, Selena, and Ben for aid in so that the two of them can then work together to save Gail and stop Caleb's rampage.
 * An unusual example occurs in The 4400 where Jordan Collier and Tom Baldwin must work together to escape a dream sequence (whose actual purpose is to get people to work together). It's an odd example in that neither character is a villain: as Tom is a government official doing its best to deal with bizarre circumstances (and sometimes engaging a some morally-questionable methods of dealing with problems) and Jordan Collier is trying to avert the end of civilization, but supports anarchy and believes everyone should take Promicin (a drug that has a 50% chance of death or super-powers).
 * In Season 3 of Heroes, Noah Bennet makes a surprising team-up with Sylar to stop the escaped Level 5 villains. The two even seem to have bonded by the end of the 3rd episode, at least until Sylar starts up with the brain-stealing again, causing Bennett to vow to kill him eventually.
 * What Noah Bennet meant could very likely refer to
 * Also, in the Season 3 season finale, Bennet frees all the Level 5 supervillains so they can help fight . They all last maybe 3 minutes, tops.
 * Season 4 does this again when Peter realizes that in order to prevent Samuel Sullivan's plans from coming into fruition, he's going to need Sylar's help. Unfortunately, it meant getting himself stuck inside Sylar's head and dealing with the latter's Villainous BSOD.
 * Subverted in Angel during the fourth season, when Angel comes to Lilah for information on the Beast and suggests they work together:

Lilah: Can kiss my ass too."


 * However, Angel eventually convinces Lilah to give him the information he was seeking, with the argument that Angel will either use it to stop The Beast (in which case Lilah wins) or Angel will die trying (in which case Lilah also wins). As it turns out he decided to, so in the end it's more played straight.
 * And in the end, she does ally with the team anyways.
 * Lost has done several times, both in regards to the survivors and the Others:
 * First in Season 3, when Kate and Juliet are handcuffed together and forced to work together to escape the smoke monster's repeated attacks. It turns out Juliet herself handcuffed them together to try and gain Kate's trust.
 * The second time occurs at the end of Season 4, when Kate and Sayid must team up with Richard and his army of Others to rescue Ben from the freighter mercenaries.
 * Then there is the reluctant team-up between Losties and the Others of 1977 in the Season 5 finale.
 * Finally, Season 6 had everyone teaming up against the new Big Bad. Ben Linus and Charles Widmore sure were surprised to find themselves working toward a common goal!
 * Happens regularly in soap operas. For example, on All My Children, lifetime enemies Adam and Palmer teamed up to kill a rapist.
 * In the first season of the BBC's Robin Hood Robin and the sheriff temporarily fight side-by-side in order to defeat a group of Saladin's assassins. In the third season Robin and Guy team up in order to
 * The Man From UNCLE had this trope as part of its central premise, as THRUSH forces the Western nations and their ideological opponents the Soviet Union to cooperate in forming UNCLE.
 * Mash: Charles Winchester, ordinarily a foil to Hawkeye and B.J., will occasionally join forces with one of them against the other (usually as part of an Escalating War), or with both of them against a common target. The latter moments tend to highlight Winchester's Jerk With a Heart of Gold qualities, given that the people he targets are always bullies themselves, such as a racist colonel, or a man bigoted against people with learning disabilities, or the insanely jingoistic Colonel Flagg.
 * One good example is the episode where Hot Lips is being accused of being a communist by a congressional aide. Without even being asked, Winchester takes a stand against the aide and takes up for Margaret.
 * In The Wire, Shotgun-toting Badass Longcoat stick-up boy Omar Little and Harper's Magazine-reading Uber-Badass Bookworm assassin Brother Mouzone team up to take on Stringer Bell after a failed Let's You and Him Fight. And it is awesome.
 * While not as big of enemies as most of the other examples, Naturally Sadie uses this a lot to get characters who dislike one of the main cast to work alongside them, usually for a school project. One memorable incident has almost the entire teenage cast working together in detention while the remaining member teams up with Mallcop -- two examples in one episode, there are many more.
 * Happens all the time in the prison drama Oz as the various factions struggle for control of the drug trade, or seek to murder a rival.
 * The title character of Merlin-1998 outright states that this is his motivation for allying himself to Uther. Uther's enemy, Vortigern, is Merlin's enemy and has joined forces with an even worse enemy.
 * In season 5 of Supernatural, Sam, Dean, and the others join forces with the demon Crowley in an attempt to defeat Lucifer.
 * An odd example when joins forces with the Winchesters and goes up against Lucifer,, since he spent most of the time he knew them tormenting them.
 * And later join forces with to defeat
 * Which is an interesting use of this trope, seeing as
 * Farscape:
 * Played straight in the "Liars, Guns, and Money" trilogy when Moya's crew recruit various aliens who had tried to kill them in the past to help them pull off a heist.
 * Played straight and subverted with John and Scorpius multiple times as John pretends to team up with Scorpius, then John is forced to team up with Scorpius to save Aeryn (twice!), then it looks like Scorpius has betrayed them but he really hasn't, then John betrays Scorpius only to have to go back and save him again. And then they end up teaming up with Scorpius again for the miniseries, still against John's better judgment.
 * Leverage has Nate teaming up with his Evil Counterpart Sterling for "The Zanzibar Marketplace Job".
 * In the Smallville episode "Asylum" Ian Randall and Eric Summers ask for the help of Van McNulty because he knows Clark's weakness.
 * This happens several times in Charmed when the Halliwell sisters must reluctantly team up with demons for various reasons that are in the best interests of both sides, such as preventing the existence of magic from being revealed to the mostly unaware human population or stopping a neutral third party whose plan, if successful, would result in the vast majority of combatants on both sides being exterminated.
 * A strange case of this happens in Season 6's two-part season finale where that season's Big Bad, corrupt Elder Gideon, teams up with his evil Mirror Universe counterpart to trap two of the sisters in the Mirror Universe where they team up with that universe's version of their most notorious recurring enemy, the demon Barbas (since demons are the good guys in that universe) before fighting and then teaming up with their own evil counterparts in order to return to their own universe. Unfortunately, that causes the two universes to become unbalanced resulting in the normal universe becoming too good and the mirror universe becoming too evil, which forces the sisters to once again team up with their evil counterparts to restore the balance between both universes by killing both versions of Gideon, who have each meanwhile teamed up with their own universe's version of Barbas. In short, the entire episode is a confusing mess of various Enemy Mine scenarios.
 * Happens in American Horror Story. Constance forms an alliance with Moira, the ghost of the woman she murdered, to dispose of a sleazy developer who plans to tear down the house.
 * Terra Nova episode "Now You See Me". Taylor and Mira's "Your place or mine" hostage struggle is interrupted by a pair of young and territorial Slashers. Leading to Taylor to hand a knife to Mira and say “We can fight each other, or we can fight them.”
 * In Kamen Rider Decade's final arc, the separate Kamen Rider worlds are pitted against each other in a giant war, with the losers being erased from existence, so naturally Riders and Kaijin put aside their differences in order to protect their universes. Tsukasa, in the meantime, tries to convince everyone to focus on the common enemy in Daishocker; it works almost too late, but then the death of Apollo Geist actually accelerates the destruction rather than stopping it. Dammit.

Pro Wrestling

 * Since most wrestlers theoretically have little say on who they either fight or team with, an Enemy Mine often occurs when an on-screen authority figure randomly decides two people who don't like each other will team up against a common enemy. This used to happen all the time with Stone Cold Steve Austin and The Rock. An example would be when Stone Cold was booked to fight The Undertaker and Rock against Triple H at Over the Edge 1998, one Raw saw Austin and Rock being forced to team together against Undertaker and Triple H. Since Undertaker and Triple H were members of the same stable, the story of the match was whether Austin and Rock (who only weeks earlier were in a bitter feud) could put up with each other long enough to survive.
 * This specific Enemy Mine would occur several times through 1999, not all of them being in official matches. For example: the SmackDown pilot in which the Corporate Ministry came together in the first place.
 * Stone Cold and The Rock would continue to find themselves unwilling partners as late as 2002, when they teamed up the week before Wrestlemania X8 to face the New World Order in a handicap match.
 * A Pro Wrestling tag-team championship can also serve as an Enemy Mine, as a Face and a Heel are thrust into a match with the titles on the line, and despite their bickering and contempt for each other, manage to win. They're then obligated to continue teaming to defend the championship, arguing and taking potshots at each other all the while, until one of them finally decides being a champion isn't worth the headache and turns on the other. A 2007 example is Matt Hardy and M.V.P. on WWE Smackdown.
 * Slightly Subverted Trope in 2008 with John Cena and Batista, who won the tag titles but were bitter enemies facing each other, and couldn't co-exist, and lost the tag titles back on their first defense the next week.
 * Even more so with Cena and The Miz who couldn't co-exist as tag team champions for ten minutes before Miz betrayed Cena.
 * Hilariously lampshaded in a backstage segment with Team Triple H at Survivor Series 2007. Kane, Jeff Hardy, and Rey Mysterio Jr call out Triple H on his numerous past offenses against them, which The Game sheepishly apologizes for. However, the team acknowledges that while they don't necessarily like one another, they like the other team even less.
 * In 2010, the rise of The Nexus Power Stable on WWE Raw saw the teaming up of former rivals like John Cena, Edge, and Chris Jericho after each got ambushed by The Nexus.
 * Subverted at Summerslam 2010, when usual Cena rival The Miz tried to play on the "need" for this (especially after Cena honestly tried to keep them together, but Edge and Jericho proved incompatible) to make Cena beg him to round out the team... by the time Miz tried to pull the trigger, Cena declared that Miz had taken too long to make up his mind and that Cena had found someone else who said yes first: Cue the triumphant return of one Daniel Bryan.
 * In a interesting twist, The Rise and Fall of ECW showed that Tazz and Sabu hated each other in real life, but ended up becoming one of the company's top tag teams prior to Tazz breaking his neck.
 * Tommy Dreamer and Raven became a tag team for a while.
 * American Wrestling Association had an angle in 1985 where the Russian faction of Boris Zhukov and Chris Markoff injured Rick Martel. Martel's friend Mad Dog Vachon came looking for revenge and turned to the only man he felt was dirty and ruthless enough to stop the Russians: his old enemy Nick Bockwinkle.
 * Often happens in Royal Rumbles and Battle Royals, as many wrestlers team up to eliminate the biggest wrestlers.

Tabletop Games

 * Mage: The Awakening generally sees the Pentacle Orders locked in battle against the Seers of the Throne. However, when a Left-Handed Legacy (servants of the Abyss) makes itself known, both sides will declare a truce and stamp it out as best they can.
 * Mage: The Ascension has much the same dynamic, with the Traditions and the Technocracy setting aside their conflict long enough to take down a Nephandus or Marauder.
 * Werewolf: The Forsaken does the same thing as well, with the Forsaken and the Pure reluctantly willing to put aside differences and put down Bale Hounds whenever they pop up.
 * Warhammer 40000 very, very occasionally has instances where the more reasonable factions will hold off on killing each other to deal with a mutual threat. For a few minutes, anyway.
 * This most commonly occurs between forces of the Imperium, Eldar, and Tau against Tyranids, Necrons, or Chaos, and matching temporary alliances may occur between Chaos, Orks, and Dark Eldar, as prominently seen during Dawn of War: Winter Assault.
 * The Eldar, being the trope they are, will often manipulate any alliance they do make so that their allies take the brunt of the fighting (and thus causalities), in essence back-stabbing their allies during the alliance, as well as overtly so 5 minutes before its usefulness ends.
 * Dawn of War II has a new mode which exemplifies this, known as "The Last Stand", where a Space Marine Captain, an Ork Mekboy and an Eldar Farseer cooperate to Hold the Line against a swarm of enemies.
 * Chaos Rising throws the Chaos Sorcerer and the Tyranid Hive Tyrant into the mix of heroes in the playmode, which technically cements, if it wasn't apparent with the widely opposing team we had before, that the gamemode is not to be taken as canon, especially when a loyalist space marine cooperates with a chaos space marine in any way.
 * In Paranoia, even if someone's ideology is directly opposed to yours (Psion vs. Anti-Mutant, Corpore Metal vs. Frankenstein Destroyers), alliances can always shift to suit the demands of the moment. You can always hose them later.

Theater

 * In The Taming of the Shrew, several men are rivals for the hand of the fair Bianca, but her father won't let any of them marry her unless her shrewish older sister, Katarina, is married off first. Realizing that there's no point in fighting each other if they don't have a chance, the suitors decide to work together to get Katarina a husband.

Video Games
""Not now..."
 * In Final Fantasy X 2, the Leblanc Syndicate, who are enemies originally, become allies of the Gullwings in Chapter 3. This is different, however, in that they remain allies for the rest of the game, even helping in the fight against.
 * In City of Heroes, in the Valentine's Day 2006 and 2007 events, the missions to unlock special prizes required mixed hero-villain teams to complete. As well, the issue 10 update included a whole hero-villain co-op zone, the Rikti War Zone.
 * Issue 12 added Cimerora, another co-op zone.
 * Finally, the annual "Rescue Baby New Year" event allows heroes and villains to team up, explicitly because the kidnapping of said baby/personification of time would be really really bad for all concerned.
 * Happens quite often in Metal Slug. Twice, the Rebellion teams up with you to fight the Mars People: in Metal Slug 2 when the Mars People betray them and kidnap their leader, and again in Metal Slug 3 when their leader turns out to be a Martian impostor. Even the ultimate recurring rival and bad-ass Sgt. Allen O'Neill fights on your side. In Metal Slug 6, both groups team up with you to fight a group of Martian-eating aliens.
 * In the Super Mario Bros RPGs, Bowser will often team up with Mario against other villains, wanting to be the only villain around. He's particularly enraged when other villains inevitably kidnap Princess Peach in the course of their plans.
 * In Mario & Luigi: Bowser's Inside Story, he does this completely unknowingly. He doesn't know that the bros are in his gut. All he knows is that Fawful has his castle, and is trying to kidnap his princess and take over his Mushroom Kingdom. Mario and Luigi do their part behind the scenes, even during the Final Battle.
 * Halo does this twice. First, at the end of the second game in the series, the human UNSC and the Elites, who were previously mortal enemies, join forces to fight the Prophet of Truth, who is planning to exterminate the former and betray the latter. Later on, right before confronting the Prophet himself, the Master Chief and the Arbiter join forces with  to stop Truth from killing everyone in the galaxy.
 * Granted, this latter alliance lasts only five minutes, and then you curse their sudden yet inevitable betrayal. Although they did at least have the minimal grace to wait until Truth was dead first.
 * Like you could really trust the Gravemind.
 * The full extent of the human/Elite alliance is explored in the ending of Halo 3.  They're not really enemies anymore, but they're definitely not friends.
 * Likewise, some of the Elites will grudgingly admit to actually having some respect for humanity now. Humanity might be inferior to the Elites on a physical level, massively outnumbered and hopelessly outgunned, but if you look at some of the things the UNSC have done... then even some of the most stubborn of the Elites have admitted that they just got their asses kicked into the Stone Age by a bunch of bloody monkeys, and actually respect humanity for its stubbornness, resourcefulness and bloody-minded persistence in the face of overwhelming odds. It helps that the Elites are a bunch of Proud Warrior Race Guys and respect for honorable and skilled fighters how their culture works.
 * Supplementary materials like the short stories that came with the collectors' editions establish that the humans had indeed earned the grudging respect of the Elites, because they were doing comparatively well in the war despite inferior numbers and technology (turning what should have been a speedbump for the Covenant into a pyrrhic victory). Further, these materials establish that the Elites are very confused why the Prophets are strictly pursuing a genocidal war of annihilation against the humans (which is secretly because the humans are the real successors to the Forerunners, not the Prophets). It turns out that, if this were just a normal Covenant war of expansion, after so many years of impressive fighting, if the Elites were in charge they would have offered humanity the option to surrender by now, and join the Covenant. They'd be slave-soldiers, but it wouldn't be the genocide the Prophets were planning. Further, the Elites think humans would be a huge step up from their current frontline soldiers, the Grunts.
 * Speaking of Bungie, while it isn't exactly an example of this trope, you do join forces with the Pfhor in Marathon, and you do so because if you do, Tycho will decide to keep T'fear from killing all of the humans. It doesn't really matter, since you just go to an alternate reality after he tries to kill you for trying to escape slavery.
 * In Devil May Cry 3, hero Dante teams up with his brother and enemy Vergil to fight the penultimate boss. It's barely cold when Vergil challenges Dante for ownership of the Force Edge.
 * Starcraft is full of those, especially in the Expansion Pack. It starts with Raynor being forced to team up with the Sons of Korhal to evacuate his Doomed Homeplanet and ends up with a three-way alliance between the Terrans, Protoss and Zerg against the Earth Directorate and immature Overmind they were trying to control.
 * Which is soon followed by a three-way alliance of the Protoss, Dominion and UED against Kerrigan.
 * That doesn't really fit the bill of 'cooperating.' It's more like 'not attacking each other until a particular target is dead.' The three forces weren't even aware of each other until they all showed up on Kerrigan's doorstep at the same time.
 * In Starcraft II: Wings of Liberty,
 * Warcraft, borrowing some plot elements from Starcraft, also has quite a few such moments, the ultimate being the battle at Mt. Hyjal where the Alliance, the Horde and the previously hostile to both Nightelves put their differences aside to stop the demons. Only to have the Alliance (now including the Nightelves) and the Horde break apart in about 4 years in time for the next game in the setting, World of Warcraft.
 * Which got its own moments of temporal alliances, such as the War of the Shifting Sands, the Opening of the Dark Portal (where the Horde and Alliance came to the aid of a neutral faction holding back demonic forces coming through the portal), and most recently, the Shattered Sun Offensive. At the same time though, both sides keep fighting in arenas, battlegrounds and the open world.
 * In Burning Crusade, there are Aldor and Scryers factions in Shattrath City which are rivals of each other on the borders of open hostilities. Players have to pick between them and befriending one means you are hostile to the other. However, near the conclusion of Burning Crusade during the Sunwell event, they finally put aside their differences and band together to form the Shattered Sun Offensive against Kael'thas Sunstrider and Kil'jaeden.
 * Another was added in Wrath of the Lich King, though it borders on Big Damn Heroes. The Alliance and the Horde work together at the Wrathgate in fighting the Scourge, which stands in contrast to them murdering each other for resources and fun everywhere else.
 * In fact, a massive part of Wrath is how the Horde and Alliance start with this and end trying to kill each other and letting the Lich King off to the side to kill them both. In Cataclysm, Deathwing has become a greater threat than the scourge was because the Alliance and Horde have lost all pretense of working together on anything.
 * In Rise of the Zandalari, Vol'jin, leader of the Horde's Darkspear Trolls, is so concerned about the uprising of the other evil troll factions, that he sends emissaries to both the Horde and the Alliance. Instead of trying to get Warchief Hellscream and King Wrynn to work together, he reaches out to the individual heroes, and the smaller groups within the Horde and Alliance that are directly in the Trolls' path.
 * Occurs in Might and Magic VII, with reformed Magnificent Bastard Archibald Ironfist assisting the party in rescuing his brother King Roland and taking on the Kreegans.
 * The climax of the Restoration Wars featured a team-up between Catherine Ironfist and a faction of Necromancers that had gotten tired of Catherine's father's rule (events earlier in the story had lead to his reanimation at the Necromancers' hands, only for him to promptly off their king and take control himself).
 * Might and Magic VIII plays with it: on the one hand, the Big Bad gives you as much help as he can give. On the other hand, the only reason he is your enemy is because of a safety protocol intended to keep him from being subverted by the Kreegans (he cannot stop once he has started the destruction of a world), so him trying to sidestep it as much as is possible is only to be expected.
 * With the Star Fox team mostly disbanded at the beginning of Star Fox Command and Fox unable (or unwilling) to get his friends back together, one of the paths you can take has Fox hiring long time rival Wolf O'Donnel to help him defeat the Big Bad.
 * And going back to Star Fox Assault, Wolf helps Fox rid the menace of the Aparoids in the last four missions.
 * Plenty in Super Smash Bros Brawl:
 * Marth and Meta Kight fighting, then.
 * Ancient Minister  helping.
 * King Dedede (by Ness and Luigi), Bowser (by King Dedede, who pointed out that there's a bigger enemy, ), Ganondorf (by Link and Zelda) and Wario (who kicks King Dedede, which King Dedede, Luigi, and Ness respond to by pointing out  to Wario, who looks uninterested. When they decide to move on without him, he races past on his bike and beats them to the Big Bad's final dungeon).
 * A comedic example is shown in Command and Conquer Red Alert 3 where the three factions (represented by their respective tanks) call a truce in the tutorial in order to teach the player not to send their units to their meaningless deaths, though are still prone to firing at each other. Usually at the Soviet Hammer tank.
 * A more serious example is also to be found in the Allied campaign when the Empire of the Rising Sun attacks-the Allies and Soviets call a ceasefire to destroy the Empire, and proceed to betray each other at about the same time.
 * This also occurs in the Tiberium series. In the expansion pack Tiberian Sun: Firestorm, the remnants of Nod and GDI have to work together to stop the renegade Nod AI, CABAL. In Tiberium Wars, Nod general Kilian Qatar allies with GDI to face off against the Scrin, until Kane reveals himself to be not quite dead, flips out, and orders GDI nuked.
 * Happens in the Yuri's Revenge expansion to Command and Conquer Red Alert 2 as well, when the Soviets and Allies team up to fight Yuri.
 * This occurs in Kingdom Hearts II when  teams up with Sora against Organization XIII.
 * Interestingly, you never really see  and Pete helping, just getting ready in a Bolivian Army Ending kind of way. Sora mentions that they've found something worth fighting for, and then we never see them again. Things are back to normal as of Coded though.
 * And also briefly when Axel fights alongside Sora to defeat a load of Nobodies. Since Roxas was lost, he became more of a Wild Card character, and from there was slowly molded into a Sixth Ranger. And it's sealed when  to open the gate to The World That Never Was.
 * Super Robot Wars Destiny is an interesting example. While the game includes antagonists from Gundam ZZ, Char's Counterattack, and Gundam Wing, the situation at hand causes them to have the competence to ally with you all at the start since things are bad enough. Due to the Zanscare Empire attacking Earth, along with the Invaders, and the Protodevlin, and the united alien forces of the villains from Daltanius, God Mars, and Grendizer, your heroes quickly realize the only organizations out there that still have the sheer manpower to defend humanity are the Principality of Zeon and the Order of the Zodiac. Roger Smith takes care of the negotiations. This results in the first heroic roles for longstanding villains like Haman Karn and Treize Kushinada.
 * Super Robot Wars likes to play with this in smaller ways as well. For instance, Super Robot Wars W has a stage where Tekkaman Evil is forced to (briefly) work with the heroes because of the takeover of Tokyo by the Zonder. On the Selena route of Super Robot Wars Alpha 3, not only does Selena herself spend some time assisting the Cruscet team, Andrew Waltfeld and his adjutant Martin Dacosta assist the Alpha Numbers in holding off an attack by the Barota in a later stage.
 * One OG example is when Sanger and Elzam storm the Tesla Liecht Institute to retrieve the Dynamic General Guardians being kept there from the Inspectors. When Sanger's Grungust Type-3 gets damaged, the Inspector Vigagi is about to land a fatal blow when Wodan Ymir appears and intervenes, claiming that he is the only one allowed to kill Sanger. Wodan buys enough time for Sanger to activate the Dygenguard, and goes so far as to be the one who helps Sanger retrieve his Type-3 Zankantou (a job that was given to Elzam in Alpha 2) to continue fighting when Dygenguard's original weapons malfunction.
 * Super Robot Wars EX is an interesting case because some of the characters you can recruit ARE enemies in their respective series that are cooperating because they are stuck in La Gias with no way back. Shu's route is unique because the only heroes you actually can recruit (on that route) are the GoShogun team and Quattro. The rest are all villains like Todd Guiness and Jerid Messa.
 * Some of the secret recruitable characters in these games are often enemy characters, such as Norris Packard, Gym Ghingaham, Jonathan Glenn and Quincy Issa, and Michael Garret and Fasalina, just to name a few.
 * This happens three times with Stripperiffic Pokémon Pincher admin Blue Eyes in the third Pokémon Ranger game. Two of these times, you even get to save her life.
 * Pyron is the Big Bad of the first two Darkstalkers games, despite many of the other characters being less than savory themselves.
 * If Kid Dracula and Castlevania Judgment are any indication, Galamoth's presence is all it takes for Dracula and his minions to become Anti Heroes.
 * Spider-Man Friend or Foe has the entire premise of its story built around this trope. The story involves several prominent members of Spider-Man's Rogues Gallery being mind controlled by another villain. Spider-Man subsequently confronts the mind controlled villains and frees them from the mind control, at which point they readily agree to join forces with Spider-Man to find, and exact their revenge upon, the one who was mind controlling them.
 * In Spider-Man Web of Shadows, Spider-Man decides to break the evil mad scientist known as the Tinkerer out of Ryker's Island to get him to build a device capable of decimating Venom's symbiote army... if only because Reed Richards Is Useless by being absent when he tried to phone him, Tony Stark and Hank McCoy are also absent, and he doesn't feel like dealing with Hank Pym. The mission where you do so also involves another enemy mine --- namely, freeing the Rhino and riding him to break through the island prison's walls. Some time later, when the Tinkerer requests that he be transferred over to the Kingpin's facilities to complete the device, Spidey and SHIELD end up forming one with the crime boss as well.
 * Notable in that Spider-Man fully acknowledges that breaking out the Tinkerer is a bad idea, and he doesn't like it (unless you're playing the evil path), but that the threat of the symbiote army is so great that he really can't wait for anyone else to show up and help him solve the problem. This and other questionable actions get him in a lot of trouble when Wolverine shows up and calls him out.
 * There's also the possibility for a third, very temporary Enemy Mine. In order to get to Ryker's you have to make one of the "good or bad" choices that are sprinkled throughout the game. Choosing the bad option has you get a ride there from the Vulture. (In case you're wondering the good option is a ride from Moon Knight.)
 * In the DS version, you can also choose the Dark path by helping the Green Goblin.
 * The plot of the Kim Possible Licensed Game "What's the Switch?", featuring a reluctant team-up by Shego and Kim.
 * Mana Khemia Alchemists of Al Revis: Hilariously played with; the True Companions go into the depths of a monster-infested dungeon, trying to find the cure for an ailing friend, and found themselves mobbed by monsters. Then comes the game's Goldfish Poop Gang (doubtful of the status as real enemies). They think they're going to cause trouble again, only to find that the latter group, under orders, is there to help them. Made even funnier by the following dialogs. During their arrival:

"We don't have time to play with you!""


 * The second dialogue is that after they reveal their plans, and persuades the heros to make their escape with the medicine:

"Renee: ... Umm, maybe you shoulda been honest and let them help.

Tony: Don't be stupid! Coming to their rescue to ask for help? That's just uncool."

": Makarov, you ever heard the old saying "the enemy of my enemy is my friend"?
 * In The World Ends With You, at one point, Neku and his partner see two Jerkass Reapers getting attacked by Taboo Noise. At this point you have the choice of helping the Reapers or letting them fight it off on their own. Hilariously, if you choose to help, Neku justifies it by saying it'll really annoy them, since Reapers are supposed to be killing Players, not being helped by them, and if you choose to leave them to their fate, Neku justifies by saying, "Just for you, Jerk face!"
 * In Sonic Adventure 2, Sonic the Hedgehog teamed up with Dr. Eggman and the rest of the Dark Story characters to stop the Space Colony ARK's automated "apocalypse" function, which is mainly the station de-orbiting to crash into the planet, presumably blowing up both if it had hit.
 * Sonic and Eggman teamed up again in Sonic Advance 3 to stop the out-of-control, Chaos Emerald-enhanced Gemerl from destroying the world.
 * Subverted in the DS version of Mario and Sonic At The Olympic Games. When Toad mistakes Omega as one of Eggman's loyal robots, Omega states that Dr Eggman is in fact his enemy. Toad questions Omega on his blockade using this trope's logic, only for Omega to simply respond with "Unverified" and restate his threat to the team. As you can guess, he does not end up assisting the team, instead preferring to take on Eggman himself. It comes as a surprise to Toad.
 * In the intro to Mortal Kombat Deception, Raiden, Shang Tsung, and Quan Chi attempt to fight that game's Big Bad, the Dragon King Onaga. Unfortunately, when Raiden realizes that they aren't doing any damage...
 * Additionally, this occurs in both sides of the story mode for Mortal Kombat vs. DC Universe.
 * In Tales of Symphonia Lloyd's group joins up with Sheena, their enemy in order to save a village from the Desians.
 * X Men Legends II had the X-Men and their old enemies the Brotherhood teaming up to fight the forces of Apocalypse, who had abducted members of both teams.
 * Some are happier about it than others. Scarlet Witch and Toad get along great with the X-Men and become quite friendly, while Magneto simply tolerates them, and Sabretooth and Juggernaut are constantly taking verbal potshots at the X-Men all game.
 * As for its successor series, Marvel Ultimate Alliance 2 does it as well: this is how the game segues from an adaptation of the Civil War to Vicarious Visions' original storyline, as the Negative Zone brawl is interrupted by, forcing the pro- and anti-registration heroes to put their political squabble aside. And it kinda does not snapback, for when is all said and done, the Civil War is settled peacefully, the winning side being the one you chose at the beginning of it.
 * The Turks, Punchclock Villains from Final Fantasy VII, find themselves briefly fighting alongside the heroes in an effort to save kidnapped Optional Members of both teams.
 * The Turks attempt to help in Final Fantasy VII Advent Children... attempt being the main word here. Lucky they've got Rufus Shinra.
 * In the first Thief, there's actually a mission named Strange Bedfellows, in which . In the second game, . In the third game, it's possible to ally with both the Pagans and Hammerites if you get your reputation with both groups high enough.
 * Fire Emblem uses this and does not Snap Back. The phrase is even used to describe Marth in Super Smash Bros. Brawl.
 * In Phoenix Wright Ace Attorney,.
 * Then in Justice For All a similar arrangement is made where
 * In Trials and Tribulations,  actually takes over the defense for the case since Phoenix   To make it even more interesting, he
 * Halfway through Advance Wars: Days of Ruin (after ), Tasha, Gage and the surviving Lazurians temporarily set aside their differences with Will and the 12th Battalion to help him stop Admiral Greyfield's New Rubinelle Army from launching missile strikes against them.
 * Nicktoons: Globs of Doom has SpongeBob SquarePants, Danny Phantom, Jimmy Neutron, and Tak and The Power of Juju joining forces with an evil syndicate (hired by Jimmy), Zim and Dib to defeat an invasion of cyclops slimes from outer space. At the same time, Zim (a Villain Protagonist and seeing only himself as worthy of conquering Earth) abuses the situation to his advantage by lying his way to the heroes' side, leaving Dib stuck with the villains, much to his dismay. Even after they Snap Back, as he's still complaining but to no avail.
 * At the end of Bomberman 64, halfway through the final battle against -- the Magnificent Bastard who used the hero throughout most of the game --, who was presumed dead earlier appears and saves Bomberman's life at the last second. After some dialogue,  forms a temporary alliance with Bomberman to take down . He even helps Bomberman escape the collapsing fortress before reminding him that they aren't friends and they will fight again.
 * Shirou and in Heavens Feel route of Fate Stay Night. They're both very clear on the fact that they're doing it for entirely different reasons and that after cooperating, they're enemies again. Still, it leads Shirou to realize that he actually likes  and that's why he avoids him. They're not actually that different apart from the whole, you know, evil for the fun of it factor.
 * And in Unlimited Blade Works, joins forces with Shirou and Rin against  on the orders of his master, . He even sticks around to  just because he feels like it afterwards, despite technically being their enemy.
 * The entire mechanics of the Holy Grail War encourage/force the Masters to get into such scenarios, since with seven factions battling each other, there will always somebody trying to score a kill while two others are fighting or an enemy one can't beat alone. Technically, Shirou's and Rin's alliance started out this way, but they never got to duke it out in the end. In Fate Zero, there also was such a scenario against Servant Caster.
 * In one of the path branches in Devil Survivor, teams up with  to keep  from pulling a Karma Houdini and getting away with his Knight Templar stint without a fight. She does so hoping she can restrain  from killing him, but wonders about her ability to do so a tad too late.]]
 * The freeware game Sonny has the titular character and Veradux team up with Galiant, an elite soldier of Zombie Pest Control Inc., to fight the super-powerful zombie Baron Brixius. Once that's done, however, Galiant turns on the other two and becomes the game's Final Boss.
 * Baten Kaitos has  helping the main party to infiltrate the The Very Definite Final Dungeon despite having fought the group multiple times over the course of the game.
 * Call of Duty: Modern Warfare 2 has the appropriately named level "The Enemy of My Enemy":
 * Call of Duty: Modern Warfare 2 has the appropriately named level "The Enemy of My Enemy":

Makarov:, one day you're going to find that cuts both ways."

"G La DOS:"
 * In The Godfather: The Game, in the cutscene of  you can clearly see mobsters from the Tattaglia, Stracci and Cuneo families working together against the victim.
 * Overlord II has the Evil Overlord offered an alliance by the Big Good Queen Fay, ruler of Light Magic to take down the magic-destroying Glorious Empire. She helps by reconstructing the Tower Heart of the first game and sacrifices her temples to power it up. When that proves to be insufficient,
 * Ssssssort of. Queen Fay
 * In Chrono Trigger, you can choose to add Magus to your team.
 * Crash Twinsanity makes this into a game feature by making Dr. Cortex a total Butt Monkey. Crash and Cortex being forced to work together usually means whacking enemies with Cortex, tossing Cortex over a gap for him to do something, clearing his path while he runs in a screaming panic, using him as a snowboard, or controlling the two as a Big Ball of Violence when Cortex decides to beat up Crash.
 * Star Ocean Till the End of Time lets you choose whether to add Albel Nox to your party. Or is it a Heel Face Turn on Albel's part? Hm.
 * You really have no choice as he's forced to join your group temporarily anyway as part of a larger enemy mine situation with the two warring kingdoms vs the invading aliens. Afterwards the war is resolved peacefully. The only optional part is whether you choose to have Albel join you for the rest of the game, or send him back to the army that loaned him to you.
 * Mass Effect 2 has Commander Shepard brought back to life by The Illusive Man, who may have been responsible for killing his/her squad in the Sole Survivor backstory, in order to combat the Eldritch Abomination out to wipe out humanity, even willing to recruit notably Badass aliens. Particularly relevant if Shepard is played as Paragon, who does not hesitate to tell TIM that he/she's barely tolerant of his organization only because no one else will help him/her and in the end.
 * Tali also hates Cerberus with a passion and she only joins the mission to help Shepard.
 * And finally Liara worked with Cerberus herself so they could bring Shepard back because she couldn't let her friend (or more) go.
 * The 2nd game even features a villainous example: the vigilante Archangel does such a good job of ruining the collective days of Blue Suns, Eclipse, and the Blood Pack mercenary gangs that they all team up to take him down, despite usually being at each other's throats.
 * Mass Effect runs on this trope anyway. You gather a team of people from various species, and almost all of them are at least a bit prejudiced against the other races due to past events such as the First Contact War and the krogan genophage. They all end up working together to save the universe from a common threat. One of those people you can recruit is
 * The geth and the Reapers do this in 3. Having declined an alliance with the "Old Machines" once before, the geth are forced to reconsider after the quarians try to wipe them out for the second time in three centuries. Faced with creators who seemingly refuse to treat them as equals and no help from any other organics, they decide that giving up their free will is preferable to being exterminated. It takes the combined efforts of Shepard, Legion, Tali and Zaal'Koris to get both species out of that mess intact.
 * This is the best way to describe the relationship between Kane and Lynch. They consistently hate each other throughout the game since Lynch was originally a thug hired by The Syndicate to watch Kane. Hilarity Ensues as Lynch's Ax Crazy nature gets the better of him...
 * The Cartoon Network MMO Fusion Fall has the heroes and enemies generally working together against Fuse. Mojo Jojo even provides the main fast-travel in the game. There are exceptions, though (a recent story arc has Vilgax screwing things up for Ben).
 * In Prototype, Blackwatch works with Alex Mercer to defend the Bloodtox Pump from the Infected, and there are also side-events scattered around the city that involve fighting with the Marines or Blackwatch to beat the Infected. However, other than these few exceptions, Mercer and the Military are mortal enemies.
 * Briefly in both Uncharted games.
 * The original has
 * Whereas in the sequel
 * In Free Space, the Terran-Vasudan War comes to an abrupt halt with the appearance of the Shivans, who are trying to kill both of them. Since the Shivans are more than capable of wiping out both species, the two agree to a cease-fire to deal with the common threat. The cease-fire holds and eventually becomes the foundation for an alliance between the two species.
 * In the fan-made Blue Planet expansion, events transpire such that both the Terran forces of the GTVA and the UEF respond to a Vasudan ship in distress. The captains of both ships agree to set aside the war for the moment to rescue the Vasudans, and the deployed fighters make small talk with their opposite numbers.
 * In FEAR 3, Paxton teams up with the ex-FEAR commando Point Man.
 * Raikov's recruitment in Metal Gear Solid Portable Ops was mostly due to this trope, as he seemed to hate Gene enough to even ally himself with Naked Snake mostly to get revenge on Gene for humiliating him and locking him up (In case why it is worded this way, its because he has a lot of hate towards Naked Snake because ) Roy Campbell even lampshades this by quoting the adage "The Enemy's Enemy is my Friend" during both the mission briefing and the radio call at the start of the mission.
 * The whole point of the Warriors Orochi games; all of the characters contained within are from either the Three Kingdoms period of China's history or the Warring States period of Japan's, and many of the characters are sworn enemies. However, a few of the Dream Mode stages in Warriors Orochi 2 specifically invoke this trope by teaming up characters who normally hate each other, such as the stage where Dynasty Warriors Guan Yu, Xiahou Dun, and Lu Meng team up to rescue Liu Chan from Samurai Warriors character Hideyoshi Toyotomi.
 * In Dragon Age,
 * Also shows up in the myriad groups you are assigned to recruit; though nowhere so much as the Dalish working alongside humans.
 * Can happen in Dragon Age II, depending on your choices and who you side with in the end. No matter how you feel about the mage/templar conflict, many people will probably side with the mages just to piss Meredith off. Also, this is Fenris' opinion on fighting alongside mages, particularly Merrill, with the implication that he won't straight-up gut them because of loyalty to Hawke.
 * In the Mark of the Assassins DLC, Tallis is revealed to be working for the Qunari, who are feared by the rest of Ferelden. This quickly earns her the scorn of most party members since they're technically now working to save a group that most of them despises.
 * Similarly, if you choose to side with the mages in the final confrontation and coerce Fenris/Aveline into joining you, or vice versa with the Templars and Merrill/Anders.
 * In Battlefield 2: Modern Combat,
 * System Shock 2 features the return of SHODAN, a rogue Artificial Intelligence who was the Big Bad of the original. The player joins SHODAN in a battle against a common enemy, The Many.
 * When you enter, SHODAN tells you that the reason she wants you to get rid of the Many is because they turned against her after the Hacker sabotaged her on Citadel Station. The Many grew up without her tutelage, and they decided that they hated the mechanical ways of SHODAN and wanted all of the universe to be covered in their organic ways.
 * Adventure Quest Worlds has King Alteon and Gravelyn, Sepulchure's daughter, into forming a Great Truce between Good and Evil to deal with the threat of Drakath and his forces of Chaos, including the 13 Lords of Chaos.
 * In the indie FPS Bet On Soldier, you spend most of the game fighting through the Bet On Soldier tournament in order to confront the BOS World Champion, Igor Boryenka, who you believe to be responsible for the murder of your wife. Once you finally defeat Boryenka, the real Big Bad punishes you both by forcing the two of you to fight together in an Arena deathmatch against wave after wave of the best fighters in the BOS League. It's actually a pretty cool level, since Boryenka retains his boss-like health and damage output, but the sheer number and skill of opponents the two of you face make it seemingly impossible for him to survive to the end.
 * In Fallout New Vegas, if you take the NCR, Mr. House or Independent path and complete sidequests pertaining to said factions, it's possible to have the NCR, Brotherhood of Steel, Great Khans and  fighting together against Caesar's Legion in the final battle for Hoover Dam. This is notable because most of those groups have been mortal enemies of the NCR throughout history, with   having been the Big Bad of the previous two games.
 * Near the end of Crysis 2, the remaining members of the CELL PMC that has spent the entire game trying to kill you end up teaming up with you against the Ceph alien invasion, because their dying boss makes it clear to them that their entire chain of command is now dead and you are now humanity's last hope for stopping the aliens.
 * In Portal 2, joins up with main character Chell after G La DOS is switched out of the main core, and pulls a Heel Face Turn some time later.


 * In Xenonauts the US and USSR work together against the alien threat.
 * Recently, a fandom example has unified the Broken Base of the Spyro fans. Both groups have come together to say NOTHING good can come from Skylanders Spyros Adventure.
 * In the Sundown Kid's chapter in Live a Live, Sundown Kid is being relentlessly pursued by the bounty hunter Mad Dog. They put their duel on hold when the town they stopped at is attacked by Odie's gang of outlaws. After working together to defeat Odie, Mad Dog will immediately try to settle things with Sundown once and for all, to the strong protests of the townspeople they just saved. Sundown can either finish off Mad Dog or spare him to fight another day.
 * In the remake of The Tower of Druaga for the PC Engine, Gilgamesh, instead of killing the Succubus, must convince her to help him so he can get the Blue Crystal Rod and defeat Druaga.
 * One mission in Perfect Dark sees protagonist Joanna Dark, captured by Skedar in the mission beforehand, locked in the same cell as the head of the very organisation the game squares you up against, Cassandra de Vries.
 * In the Skyrim quest Cure For Madness, you have to hunt down after he apparently turns rogue and attacks . However, you can choose to spare his life, and later he will act as a follower for you. Similarly you can play as an Imperial, High Elf, Dark Elf, etc whilst working for the Stormcloaks (who are known for the xenophobia of some members).
 * Solatorobo has the Kurvasz Hunters, Howler Sky Pirates, and a train conductor join forces to
 * Neverwinter Nights 2 has an example that would not be allowed in a pen-and-paper game of Dungeons and Dragons. Namely, having Casavir and/or a paladin Knight-Captain work side-by-side with Bishop (Chaotic Evil ranger) and Ammon Jerro (Neutral Evil warlock). Thankfully the "Code of Conduct" paladin class feature is not present in NWN2, or else the game would be Unwinnable By Mistake since Jerro is the undisputed expert on the Big Bad.
 * The final chapter of Baldurs Gate Dark Alliance 2 has The Hero, Jherek the Harper, and Kharne the Zhentarim mercenary team up against the vampire Mordoc Selanmere.
 * Mid- to late-game players of recent games in the X Universe series can befriend the Yaki faction by various means. They can then make use of their NGO Superpower status to steal ships from "Return Ship" missions, by docking the ship at the shipyard in Senator's Badlands. The Space Police sent to destroy the stolen ship will spawn and immediately come under attack by the Yaki, who have an Akuma destroyer at their disposal.
 * In Kid Icarus Uprising, immediately after a Melee a Trois between Pit,, and , the fight is put on hold to deal with out of nowhere. Though  still can't resist dropping a Chest Monster in Pit's path at every opportunity,  takes to the team-up very well, and remains a tenuous ally for the rest of the game.

Web Animation

 * Red vs. Blue, as mentioned above, in which the red and blue teams often join up to battle O'Malley, and later the Meta.
 * Haloid. When Samus and MC first meet, Samus attacks MC for no good reason and they start a running battle. When more Covenant troops show up, Samus and MC join forces to fight them, including a Back-to-Back Badasses moment.
 * Not entirely for no good reason. Niether Samus nor MC recognize the other as human at first, and each presumes the other to be more of the enemy. Once Samus is down to her Zero Suit, MC stops attacking her, and once Samus gets a good look at   through the visor, she stops attacking   as well.
 * In episode 9 of Mega Man Dies At the End,  have to work together to escape from the guards.

Web Comics
""My puzzling ally--pulling me by hand,
 * Schlock Mercenary lampshades this with Maxim 29 from The Seventy Maxims of Maximally Effective Mercenaries: "The enemy of my enemy is my enemy's enemy. No more. No less."
 * During the "Dangerous Days" arc of Sluggy Freelance, the gang's (first) trump card against Hereti Corp is.
 * Also, due to his Sociopathic Hero nature, almost any time Bun-Bun is persuaded to help the other characters has shades of this.
 * In The Order of the Stick, Elan and Thog temporarily team up to escape from prison and travel back to the Order after Elan "fast-talk" Thog. Being both Cloudcuckoolanders, they get along surprisingly well.
 * While Elan sees  Tarquin as evil and doesn't want his help at first, later when it comes to defeating Nale they rather Agree to Disagree.
 * In the Prequel, the appropriately-named Start of Darkness, Right-Eye attempts (unsuccessfully) to ally with human wizard Eugene Greenhilt, despite hating humans, in order to eliminate the threat Big Bad Xykon poses to his own goblin minions.
 * The Light Warriors of Eight Bit Theater are in a constant state of this. It's stated that the greatest threat to the team is each other.
 * Basic Instructions: How to Unite Against a Common Foe
 * In Homestuck, the Prospitian and Dersite armies briefly unite against Jack before being slaughtered en masse; the survivors are pretty chummy from then on.
 * In Kiwiblitz, when Blitz' kiwi mecha gets impounded, she decides to steal it back. She enlists the help of an earlier foe, a master thief known as The Raccoon.
 * In Fafnir the Dragon, the far right wing of the Republican Party allies itself with al Qaeda to kill Barack Obama on the day of his inauguration, which sets off the first arc of the series.
 * The pirates and the Imperial Guard of Dubious Company are forced into this after Izor's Amazing Plan gets screwed and throws everyone into an alternate dimension.
 * Penny and Aggie; during the "Popsicle War" arc, when Meg and Karen and their clique(including Charlotte and Cyndi) executed increasingly cruel stunts against both Penny and Aggie and their respective friends, Penny(whom Aggie had previously seen as a friendly enemy) forged a truce with Aggie to stand against Meg and Karen. This led to Penny and Aggie becoming Fire-Forged Friends (and in later arcs something more...). During the final arc, Aggie wrote a sonnet about her history with Penny, summing up the Popsicle War arc with this stanza:

From deep depression's suffocating pool

She joins my friends to hers, making a band

Of sunshine fire, to fight the truly cruel.""

Web Original
"Master: You know, Doctor, I believe TV Tropes calls this situation "Enemy Mine". It seems we must join forces to face this common threat.
 * In The Gamers Alliance, Kagetsu I begins working with the Grand Alliance against Arawn Losstarot when the Alliance saves Kagetsu's wife Marya from Arawn's stronghold. Likewise a group of clerics of Mardük and Samachi work with the Alliance against the Northern Horde during the battle of Vanna despite their animosity which stems all the way from the Great War.
 * In Survival of the Fittest, Shameeca Mitchell and Heath Trennoby enlist the aid of Anti-Villain Bobby Jacks in order to mount a rescue from all around asshole Lenny Priestly. Admittedly Shameeca hadn't met Bobby before this point, but she was well aware that he was a killer.
 * Doctor Who The Abridged Series lampshades it in part two of Logopolis Abridged.

Doctor: -sigh- The fangirls are going to have a field day with this..."

Western Animation
"Bushroot: "Hey, I may be a mutant plant-duck, sure, but I'm an Earth mutant plant-duck!""
 * In Transformers Generation 1 it's not unusual to see the Autobots and Decepticons (or expies of them) joining forces to take on a greater threat. It just takes a greater threat to make them do it. Usually Unicron, but not always.
 * In Transformers Animated, during the second season finale,
 * In the G1 episode The Insecticon Syndrome, Megatron and Optimus Prime fight together against the out-of-control Insecticons. Watching Optimus grab up Megatron's semi-conscious body and force-fold him into gun mode is interesting.
 * In the G1 episode Countdown to Extinction it's Megatron and Optimus Prime cooperating again to stop Starscream's Doomsday Device. Watching Optimus worry over the damage Megatron is taking to unbolt the device is fascinating.
 * In Beast Machines, the Maximals join forces with the surviving Vehicons to survive when Savage appears.
 * Earlier, in Beast Wars, this happened a ton between the Maximals and the Predacons, always during story arcs where the Vok, the godlike beings using Earth as their own Petri dish, become active again. For example:
 * The entire final arc of the first season kicks off with Megatron attempting to form a truce with the Maximals when it becomes apparent that the Vok are a much greater threat to both of them than each other.
 * In season two, when an alien ship appears that put Tigatron and Airazor on a long bus ride, the two factions team up to try to break into it, but all bets are off when Megatron gets control of the ship and all its power.
 * Transformers Armada is technically an anime, but whatever. In any case, its very title refers to the Autobot-Decepticon alliance formed in the final episodes to combat Unicron.
 * Transformers Prime. The Autobots temporarily team up with Megatron to stop Unicron from awakening.
 * Justice League, "The Return". Lex Luthor is forced to work with the League to stop AMAZO, an android he himself had loosed on them in an earlier episode, from killing him. This applies to the League more, as AMAZO isn't out to do anything else not in his way (he moved Oa to another dimension because it was easier than fighting, and fought back against the League because they attacked him), but he is after Luthor, who deceived and manipulated him. The League figures that the android will kill Luthor (at this moment in the series, in a Heel Face Turn), so THEY decide to help HIM. Part of it was because it was personal to GL John Stewart, as they didn't know he just moved Oa. They saw him approach the planet, give off a flash, and then it was gone.
 * Lex Luthor and the entire Legion of Doom were forced to help the Justice League defend Earth from invasion by Apokolips. It was a collective decision of "the only one allowed to take over the planet".
 * Wonder Woman and Hades against Felix Faust although this wasn't by choice. She was ordered to reinstate Hades by the Gods, and when she still had some reluctance, it ended when Hermes pointed out how Faust was indirectly harming Wonder Woman's magical friends by usurping Hades' post.
 * In Code Lyoko episode "Marabounta", Jérémie's newest attempt to destroy XANA goes haywire and threatens to destroy Lyoko itself. XANA sends monsters to help the good guys destroy the threat. When the combined team is victorious, the heroes expect the monsters to immediately turn on them. Instead, the monsters bow and then leave without incident.
 * In the following episode, "Common Interest", Jérémie and XANA team up to save Lyoko and Aelita when the uranium battery that powers the Supercomputer starts dying. This time however, XANA does strike back immediately after the teamwork is through.
 * In the animated TV show of The Neverending Story, the main character teams up with the evil female character, who even saves him at one point.
 * Avatar: The Last Airbender
 * In "The Blue Spirit", when Zuko (in disguise) rescues Aang from Zhao because Zuko needs to be the one to capture him.
 * In "The Chase",
 * When Zuko
 * Darkwing Duck once teamed up with electrical supervillain Megavolt against an enemy that threatened to destroy St. Canard. When Gosalyn asks Megavolt why he's helping out, he explains that if the Big Bad destroyed the city, there'd be nothing left for him to rob.
 * And Megavolt did so again, along with Fearsome Five teammates Bushroot, Liquidator, and Quacker Jack, when team leader Negaduck steals their powers with a magical gem. (Quacker Jack had no power to steal, other than his wackiness. That's your cue, fellow tropers!)
 * And Megavolt teamed up with Darkwing again in order to stop the Gosalyn-shaped representations of radio, light, and heat waves from wreaking havoc upon the city. His excuse for the team up this time? The physical representations of the electromagnetic spectrum hurt his feelings.
 * Also, Darkwing Duck teamed up with Ineffectual Sympathetic Villain Bushroot a few times, most notably against an invasion of evil cabbages from outer space.

"Skulker: Now, go! Defeat him, so I will be free to hunt you another day!
 * And Quackerjack in "The Haunting of Mr. Banana Brain."
 * Robin must reluctantly team up with Slade to save Raven in Teen Titans. Slade uses this time trying to annoy Robin as much as possible, naturally. Later Slade helps them out with Trigon with his extremely bad-ass antler cutting fiery ax.
 * Also the Titans team up with Gizmo to rescue Cyborg. Actually, Gizmo has no choice in the matter as Raven threatens to turn into some demon-monster and devour him if he doesn't.
 * Robin also teams up with Red X in "X" to stop the theft of a dangerous substance. While the last time we saw Red X,  this time the )
 * A similar plotline occurred in The Batman, when the villainous residents of Arkham Asylum, freed by an alien invasion, join the fight against the aliens, with the Joker angrily stating that causing mayhem in Gotham is his job. He goes so far as to gleefully proclaim that the whole world has gone mad after seeing Gordon and Freeze protect each other's backs.
 * Despite his declaration of "just this once" (quote at top of page), Zim and Dib of Invader Zim have teamed up at least three times against various crises.
 * Notable episodes: "Bolognius Maximus", "Hamstergeddon", "Halloween Spectacular of Spooky Doom", and "Tak: The Hideous New Girl".
 * Subverted in "Planet Jackers": Zim reluctantly tries to form an alliance with Dib, as he requires Dib's telescope (Zim's has been broken). Dib refuses to believe Zim has (somewhat) good intentions and kicks Zim out of his house without allowing time for an explanation.
 * Lampshaded in "Walk for Your Lives": Zim forces an alliance on Dib, who is the only way to stop a massive slow-motion explosion. Dib (who's also in slow-motion) gets fired out of a cannon into an explosion, causing it to speed back up and finish already. But it's still an alliance.
 * Not really. If being captured counts as being an ally, was Dib helping Zim destroy the world in "Future Dib"? He vehemently objected to the plan, and it's not like Zim flung him at the explosion for anyone's benefit but his own.
 * There's another subversion in "Gaz: Taster of Pork," when Dib, evidently at the end of his rope, winds up going to Zim for help. He cites their partnership in "Bolognous Maximus" (which is an odd Continuity Nod to an episode that ended on a Snap Back), but Zim just screams "YOU'RE MAKING IT UP!" at the top of his lungs at him.
 * Danny Phantom
 * Danny and his ghost hunting rival/enemy Valerie work together to outdo Skulker once they stop trying to torment one another. Being handcuffed together didn't help matters.
 * In the first movie, "Reign Storm", Danny, Vlad, and Valerie had to team up to try and take down the much greater threat that was Pariah Dark. In fact every enemy ghost came to help out during the final battle.
 * Except Dark Danny, for obvious reasons.
 * During the final battle:

Danny: (to Ember) Guy really knows how to motivate you..."

""Oh my god, now we have a common enemy, we have to work together.""
 * Danny teamed up with the rest of his foes to break out of Walker's prison in "Prisoners of Love."
 * Danny and every single ghost in existence teaming up to turn the Earth intangible in "Phantom Planet." Wow, he does do this a lot!
 * In the Christmas Episode, when the Ghostwriter tried to teach Danny a lesson, all other ghosts Danny met in the episode agreed to help him because the Ghostwriter broke the Christmas truce.
 * In "Livin' Large", the Guys in White tried to blow up the Ghost Zone, unaware that it'd destroy Earth as well, and Danny teamed up with some of his ghostly enemies to stop them.
 * Danny and Valerie teamed up again in "D-Stabilized" to defeat Vlad and.
 * The Raccoons episode "The Intruders" has the bad guy Cyril Sneer working together with the titular raccoons and their friends in order to save his own son and one of the raccoons who got trapped in his supersafe vault.
 * In The Pirates of Dark Water episode "The Game Players of Undar", frog-like creatures effortlessly capture both the main hero and the main villain, handcuff them together, and force them to work together to win a dangerous game on an island for their own amusement.
 * Batman the Brave And The Bold:
 * In the episode "Game Over For Owlman", Batman is forced to team up with after the rest of the heroes of the series become convinced he has become a bad guy thanks to the machinations of his Evil Twin Owlman.
 * And again with Two-Face in the beginning of "The Fate of Equinox", after his hired henchmen go against his decision to spare Batman.
 * Commander X-2 did this with Duck Dodgers and his Cadet on occasion -- especially when his Queen was in direct danger. Awwwww.
 * An episode of The Powerpuff Girls had them needing Mojo Jojo's help to beat this huge alien thing that was so evil even Mojo considered it his superior.
 * Another episode had the Gangreen Gang helping the girls to defeat Sedusa after she abandons them when she no longer needed them for her plan.
 * In an episode of Adventures of the Gummi Bears, Toadie's cousin Tadpole takes over Castle Drekmore, kicks Duke Igthorn out, and orders the ogres to destroy all the gummiberry bushes. Neither Igthorn nor the Gummis want the bushes destroyed, so they reluctantly team up to get rid of Tadpole.
 * In another episode, Duke Igthorn hires a bounty hunter to catch a Gummi Bear. When the hunter returns with Cubbi Gummi but Igthorn refuses to pay, he and Cubbi are tossed into a dungeon cell, and have to work together to escape. That episode was a Chained Heat, as well.
 * In The Fairly Odd Parents "Wishology" trilogy, all of Timmy's friends and allies except for Mark are captured. Needing help, he recruits Vicky, Crocker, and Dark Laser to battle the Darkness. He needs to offer them something: 20 dollars, a look at his fairies, and an opportunity to destroy him when it's over, respectively.
 * Happened several times on Gargoyles. David Xanatos is such a Magnificent Bastard that the Manhattan Clan always suspected they were being used. Occasionally they were wrong.
 * Bart and Lisa from The Simpsons teamed up with Sideshow Bob in "Brother From Another Series" to stop Bob's brother, Cecil, from blowing up the Springfield Dam to destroy the evidence that he cut back on construction to embezzle funds.
 * While not quite an enemy mine per se, they also had some help from Sideshow Bob in identifying the real culprit of Homer's kidnapping in "Wedding for Disaster"
 * In Star Wars the Clone Wars, as part of the Nightsister trilogy, Asajj Ventress is betrayed by Dooku. Seeking vengeance, she recruits none other than, Savage Opress, to infiltrate Dooku's inner circle as his new apprentice and ultimately assassinate him. However, in so doing, she forces him to kill his own brother as a demonstration of his loyalty and rage and then proceeds to treat him just as badly as Dooku treated her that Savage's loyalty to Ventress is only held together via brainwashing techniques and Savage's mutual hatred of Dooku, manifested after Dooku ceaselessly tortures him with force lightning.
 * This finally results in the ultimate battle, in which Asajj and Savage finally team up to bring down Dooku. However, during the battle, Asajj callously makes it apparent that Savage is really just her pawn, causing him to furiously force choke Dooku and her, which in turn causes them to briefly ally against him before turning on each other again. Then there's the fact that Anakin and Obi-Wan, the Jedi sent to pursue Savage following his brutal rampage on Devaron, and the Separatist Droid Army unwittingly aid each other in battling Savage following Ventress' escape from the battle..
 * In the finale it's Savage and  versus Ventress and  . Enemy Mine indeed.
 * In the anti-drug episode of G.I. Joe, the Joes and the Cobras recognize a common enemy in the drug kingpin Headman and enter an awkward alliance to take him out.
 * They also team up against "The Gamesmaster" after he captures members from both sides.
 * Happens often in the Ben 10 franchise. Ben's teamed up with Kevin, a Highbreed, Darkstar, Charmcaster, and Vilgax.
 * Buzz Lightyear and the Evil Emperor Zurg work together to beat aliens that intend to conquer the entire galaxy, including Zurg's home, in an episode of Buzz Lightyear of Star Command.
 * In the WITCH season two episode "W is for Witch", Will decides to recruit season one Big Bad Prince Phobos and his crony Cedric in subduing Nerissa. The end result? The start of a Gambit Pileup that doesn't end until the series finale!
 * Winx Club got in on this as well. Season 1 saw the Cloud Tower student witches moving in with the fairies at Alfea to fight the Trix, and one of the major complaints about this arc is that they're nowhere to be seen during the battles. Season 2 features this trope again at CT, and although Musa and Layla are briefly shown fighting the Trix together with the student witches, they're again nowhere to be seen afterwards. Although the events of S1 haven't been completely forgotten by the time of the S2 arc, the witches still dread teaming up with the fairies.
 * The He Man and The Masters of The Universe episode "The Witch and the Warrior". Teela and Evil-Lyn are forced to work together when they are stranded in the desert and Evil-Lyn has been Brought Down to Normal. One of the most popular episodes due to all the Les Yay.
 * One episode of She Ra Princess of Power featured She-Ra and Hordak accidentally sent to another dimension and having to join forces to return.
 * The fifth season of the 2003 Teenage Mutant Ninja Turtles 2003 series features the Turtles (along with the Ninja Tribunal's human accolades and the Justice Force)
 * In the Grand Finale of Kim Possible, the title heroine and her partner Ron team up with their longtime foes Drakken and Shego to save the planet from an Alien Invasion. Ironically, Drakken (who never once succeeded in his career as a Mad Scientist, this even being lampshaded by his rival Dementor), came up with the plan to use his newly acquired plant powers to stop the alien war machines.
 * There were previous instances of Kim and Shego joining forces against a common enemy: Kim enlisted Shego's help against an old Team Go enemy in "Go Team Go", and Shego stopped Drakken's new sidekick from beating Kim in "Mad Dogs and Aliens".
 * Re Boot does this in its second season finale. Bob is forced to team up with Megabyte and Hexadecimal to stop the Web from destroying Mainframe. However Megabyte, being the Magnificent Bastard that he is, takes advantage of the situation to betray Bob and strand him in the Web.
 * However, an earlier episode has Megabyte actually honoring his commitment. Megabyte's goons steal game energy in an attempt to break into the Archives. Unfortunately for Megabyte, he gets trapped in the game that they steal the energy from. When the User loads a new game and it collides with the current one, Megabyte gets trapped sinking into quicksand while being shot at by a T-Rex with a machine gun. After begging Bob for help, Bob decides to save him. Later in the same episode, Megabyte kidnaps Enzo. After the gateway command is he stole is destroyed, Bob reminds him how he saved him in the game he lets Bob save Enzo without a fight. As they're leaving, Megabyte says, "Now we're even, guardian. Now we're even.
 * The main plot of Mulan II required the protagonists, under the Emperor's orders, to travel over to Qui-Gong to forge an alliance with the kingdom in what is essentially an enemy mine gambit to defend China from the Mongolians' imminent invasion.
 * An episode of Jimmy Two Shoes had Lucius team up with Jimmy to defeat Genius!Beezy. Also Heinous vs Clown was made of Enemy Mine.
 * The 90s X-Men animated series did this with every appearance of Magneto after his introduction. Every. Single. Appearance. Except for one time when he helped Apocalypse capture a psychic-empowered mutant for his master plan. It got to the point where, during the Grand Finale, he was considered an honorary X-Man, and showed as part of the team in the final shot of the series.
 * In the X-Men Evolution episode "Survival of the Fittest" they worked with the Brotherhood to stop The Juggernaut. Then at the end of season 2 the X-Men and Brotherhood teamed up against first Magneto's team and then the Sentinel, the arc plot for season 3 involved everyone trying to stop the unsealing of Apocalypse, and season 4 ended with Apocalypse and his four mind-controlled Horsemen against the X-Men, the Brotherhood, Magneto's team, and the now-SHIELD-controlled Sentinels.
 * In The Spectacular Spider Man, Spidey made a temporary alliance with the Rhino to destroy a specs program which gave the owner the instructions on how to make more Rhino-armored supervillains. The original Rhino wasn't too happy about that, so after battling Hammerhead and Silver Sable for it, Spidey offered a team-up. After it was destroyed, however, things went back to normal...
 * Spider-Man also made an unofficial alliance with Tombstone to take down their mutual foe, the Green Goblin.
 * A non-combat version occurs on Family Guy when Brian tells Francis that they have to work together to stop Peter's new religion.
 * There's also their Show Within a Show "Bigger Jaws" which parodies the concept, by having boaters fight off a shark until a bigger shark comes along, scaring them both.

"The Coon: [voice over] I had no choice. I was at the end of my rope. Sometimes when a superhero needs answers, he has to turn to the wretched underbelly of society. I didn't want to resort to this, but he could have the answers I need.
 * Megas XLR did this when Coop and Gorath got trapped in a Mirror Universe and were captured by Mirror!Jamie. Then Mirror!Jamie joins the Enemy Mine when Mirror!Coop shows up to kick their asses. This one almost became permanent after Coop and Gorath succeed in defeating Mirror!Coop, but then Megas trips and ends up destroying Gorath's entire army. That ends the team-up.
 * The New Adventures of Superman episode "Luminians on the Loose". After Lex Luthor brings the title creatures to Earth, they turn on him and try to kill him. Luthor is forced to team up with Superman to defeat them.
 * Played with on South Park when the Coon asks for Professor Chaos' help with Mysterion, which is actually more of a Villain Team-Up.

Professor Chaos: How utterly delightful! The heroic and mighty Coon come to put a stop to me again.

The Coon: I'm not here to stop you this time, Chaos! I need information.

Professor Chaos: Oh I'm sure you do. But you see I also know you like to beat me up.

The Coon: I didn't call you to fight, Chaos! I came to see if you know Mysterion's identity.

Professor Chaos: Oh I'm close. And I'll put an end to him, and all of you goody-two-shoe heroes!

The Coon: Listen to me! I want to... help you... get rid of Mysterion!

Professor Chaos: Why would you help us?!

The Coon: Because Mysterion is trying to say he's the hero this town needs! But that's my job!

Professor Chaos: But you both fight for justice and good.

The Coon: Yeah, but he's a fuckin' dick! I want him gone just as much as you do!

Professor Chaos: Very well. I will show you what we know about Mysterion's identity, but if this is some kind of setup-

The Coon: I'm the good guy, Chaos. I don't betray people.

Professor Chaos: Weh- oh yeah.

The Coon: [voice over] I didn't like having to work with this scumbag. But I knew Mysterion was out there, plotting his next move.."


 * Hurricanes episode "Target: Winston" had Winston Honeychurch fearing for his life. Amanda Carey had, at first, believed Stavros Garkos, the series' main villain, was behind this and, along with Stats, went to his hotel room to spy on him but were caught. Wanting to know what Amanda was up to when she accused him, the this time innocent Garkos told his main thugs, Wyn and Genghis, to help her.
 * Xiaolin Showdown has the Card-Carrying Villain Jack Spicer save the Xiaolin monks from the re-humanized evil sorceress Wuya. He then explains that he's willing to provide any help they need in order to defeat Wuya, since he sees her as a threat to his own plans of world domination.
 * Batman the Animated Series had an episode called "The Trial", which featured the city's new District Attorney blaming Batman for all the superpowered criminals in Gotham City. This eventually leads to the DA being kidnapped by the villains and Batman being captured while trying to rescue her. The villains then put Batman on trial for ruining their lives and turning them into criminals, and they make the DA serve as Batman's defense lawyer. The DA demolishes the villains' claims one by one, pointing out that they were all responsible for their own problems and would have become villains anyway; the only thing Batman really influenced them to do was wear costumes. The villains are forced to acquit Batman, but they decide to kill him and the DA anyway For the Evulz. Now that the DA has done her job, it's time for Batman to do his...
 * Rejected in The Dreamstone episode "The Statue Collection", when both sides get stranded on a desert island and Sgt Blob and Albert are antagonised by a sea monster, Frizz and Nug quickly assemble a war device to fend it off. Rufus and Amberley, convinced it's doing more harm than good (and likely still pissed about them turning Pildit into stone) knock the two out, leaving Albert to take care of the monster by himself.
 * Played more straight in "The Dark Side", after the Urpneys capture the heroes, they are attacked by another monster. The Dream Maker negotiates with it in return for the Urpneys releasing them.
 * Shere Khan assisted Baloo in a few Tale Spin episodes. Also in "Stuck On You" where Don Karnage must make a truce with Baloo when they are accidentally glued to each other (and his crew create a mutiny).
 * Recess had at least two instances where Randall ends up forging a temporary alliance with TJ and his friends to take down another character. Ironically, both instances involve them being one of the few times Randall doesn't snitch on the group.
 * In season two of Avengers Earths Mightiest Heroes, the Masters of Evil were forced to team-up with the Avengers against the Enchantress and the Executioner, who were killing off the Masters one-by-one in a Roaring Rampage of Revenge.

Real Life

 * The proverb is of either ancient Arabic or Chinese origin, but the closest you're going to get to a Trope Namer is Niccolo Machiavelli, who coined this principle: The neighbour is the natural enemy; hence the neighbour to the neighbour is the natural ally.
 * This happened a lot during World War II:
 * Mao's Communist forces and Jiang's Guomindang forces called time out and fought the occupying Japanese together. Both sides were frantically trying to ensure the other side was going to take the majority of casualties.
 * Though, this ended up more around the lines of the Guomindang forces doing most of the work while the Communists avoided most of the fighting, doing only small scale guerilla warfare, and occasionally firing upon Guomindang forces, as well.
 * The Soviets and Nazis declared a nonaggression pact, though both considered it merely a stalling action before war broke out. Germany broke the treaty first and attacked.
 * Specifically Germany wanted USSR out of the way so that they could defeat Britain and then attack USSR because they wanted to avoid a two front war. USSR wanted to wait as long as possible so that they could get their factories and army up to full capacity. Obviously Germany never took Britain and attacked USSR before they were entirely ready, thus causing a two sided war.
 * Part of Nazi Party stated policy was to a) destroy the Communist threat to the German state and b) annex, ethnically-cleanse and settle the Slavic lands as part of the ideology of obtaining 'Lebensraum' for ethnic Germans. It is very unlikely that Hitler ever intended to honour the pact.
 * Actually, Stalin knew that. He believed that Germany would eventually invade the USSR. The reason he entered the non-aggression pact was to buy time to prepare for the invasion.
 * There is evidence that at one point Germany offered to let the USSR join the Axis, but the USSR wanted too much in exchange (control of Finland, Turkey, and eventually the Persian Gulf). Plans to invade the USSR were drawn up soon after.
 * In Mein Kampf Hitler declares his intention to conquer USSR. It appears that the Soviet Union was the only place where it was read.
 * The United States, Great Britain, and the Soviet Union worked side by side to defeat Germany, Japan and Italy
 * Winston Churchill was a staunch anti-Communist, but he promised help to the Soviet Union immediately after Hitler attacked it. He once said, "If Hitler invaded Hell I would make at least a favorable reference to the devil in the House of Commons."
 * Various people classified as sub-humans by the Nazis, such as Japanese, Chechens and Indians, teamed up with the Nazis against a common enemy (the Soviet Union for Chechens, Britain for Indians). Many slavonic people actually served in the Wehrmacht itself.
 * Only the very small number of Indians sided with the Axis, and were generally of little consequence.
 * Also, Hitler considered Chinese and Japanese to be "warrior races" because of their fine recent (well, ancient for China, who Hitler actually preferred to ally with but they couldn't hurt the British as much as Japan) history.
 * Complicated further by Hitler never wanting to go to war with Britain. In fact it's been suggested that he originally wanted an Anglo-German alliance and he initially admired the British for their military and empire-building capability.
 * Infamous American gangster "Lucky" Luciano bargained for his release from prison after claiming that he could protect American wharfs from saboteurs with gangster muscle. Some people suspect that it was actually Luciano's men, if anyone, who were causing the problems in the first place.
 * Luciano also supposedly made available contacts in Sicily to military intelligence during the Italian campaign, a claim that he also later denied. Given that the Fascists intended to wipe the Mafia out, the claim has some credence.
 * This tendency was also repeated again in the African countries of Chad and Somalia, when the warring forces teamed up to kick out the foreign invaders. In Chad's case, the government and rebel forces united to fight the invading forces of Libya, while the Somalis temporarily put their civil war on hold to kick out the United Nations force sent to restore order after the collapse of the dictatorship, before they returned to fighting among themselves.
 * During the fifth century BC, the Spartans and Athenians teamed up to fight the Persians.
 * Can probably be applied to the vast majority of wars, including the alliances against Napoleon.
 * During the Cold War, this was practically official policy for both sides.
 * In an ideological level Fascism and capitalism joined together (or more accurately, Capitalism put in fascism) in Latin America against the threat of Communism. An exact opposite of what was viewed in WWII: Communism and Capitalism vs Fascism.
 * The "Robbers' Cave" experiment. Two groups of boys at a summer camp were first isolated from each other and encouraged to form a group mentality. After a few days they were introduced to the other group in a competitive environment in order to produce inter-group friction. This stage was ended early when the hostile rivalry reached potentially dangerous levels. The groups were then given mutual "superordinate goals" forcing them to work together, and the hostility evaporated as quickly as it had appeared.
 * Militant feminists and conservative Christians disagree on almost every issue, with the exception of one: they are both opposed to pornography. The feminists feel that it's exploitative of women, while the Christians feel that it's immoral and sinful.
 * Lately, Christian anti-porn activists have started co-opting many of their feminist rivals' arguments that porn exploits women, partly to support their case, and partly to shake off the impression that conservative Christianity is anti-woman.
 * The odd alliance between the Religious Right and militant feminists on the subjects of porn and prostitution has been frequently Lampshaded and criticized by more moderate "sex-positive" feminists. There's considerable debate in the feminist camp as to whether or not sex work is exploitative, especially when the participants are fully willing.
 * It gets better. A proposal to create a ".xxx" top-level domain for internet porn was recently approved by ICANN, resulting in an alliance between the Religious Right (who fear that it will legitimize pornography) and much of the porn industry (who fear that it will lead to tighter regulation) against it. Alliances don't get much stranger than that.
 * Similar to the issue of the ".xxx" top-level domain for internet porn, both the Religious Right and the porn industry are opposed to making it legal for women to go topless. The former believe that it's immoral, while the latter... Well, they feel that it would dramatically decrease business for them -- since there would no longer be a demand for "topless pornography".
 * Except, in several states (including New York) it IS legal for ANYONE to go topless, as long as they don't enter private businesses that request you not to.
 * Margaret Atwood's The Handmaid's Tale has this unusual alliance to blame at least partially to cause the creation of Gilead.
 * Similarly, the alliance between militant feminists and the Christian Right in banning the wearing of burqas (as seen in France and Belgium). Militant feminists think burqas oppress women and restrict their rights while the Christian Right tend to cite "fundamentalism" creeping into society. Although burqas are banned in several explicitly Islamic nations already, so it's a bit more complicated than that, and burqa bans create an enemy mine on the other side of the fence: religious Muslims and political liberals (in the "small l" sense of "let people do what they want within reason."
 * The list of things these two factions agree on gets longer: both have been critical of heavy rock music, have shown a liking for purging libraries of controversial books, both favor harsh 'law and order' stances against sex crimes, lean towards thinking that All Men Are Perverts whom it is woman's duty to set on the straight and narrow and in extreme cases, fully believe that Sex Is Evil.
 * It seems that the enactment of Prohibition in the US was facilitated by some very strange bedfellows indeed -- Klansmen allied with militant labor unions?
 * Islamic and Christian fundamentalists are generally opposed to each other, with the subscribing to opposing religions and all. However, creationist works and arguments critical of Darwinism tend to pass between both groups, as do tracts critical of homosexuality.
 * The ongoing problem of piracy near the coast of Somalia has occasionally forced the naval forces of countries that would otherwise be enemies to invoke this trope by fighting together in skirmishes against the Somali pirates. A notable example of this was seen when the crew of the American USS James E. Williams fought alongside North Korean sailors to defeat pirates who had captured a North Korean cargo ship in late 2007.
 * Not so surprising, as piracy has long been regarded in international law as Always Chaotic Evil.
 * The Iranian Revolution brought together (for a brief period of time) leftists, communists and fundamental Islamists.
 * Also during the Iran Iraq War, Iran received a great deal of weapons and aid from Israel, because both countries considered Saddam Hussein a far greater enemy (Hussein in fact disseminated a notorious pamphlet written by his father-in-law titled "Three Whom God Should Not Have Created: Persians, Jews, and Flies"). Historian Trita Parsi has also claimed that Israel's bombing of Iraq's nuclear facility at Osirak was assisted by Iranian intelligence, but Iran officially denies this.
 * The 2001 uprising in Herat for the US and Iran against the Taliban.
 * Though they have yet to actually team up in a war, the Kurds and the Armenians, formerly bitter rivals, actually have somewhat friendly relations now that the Kurds and the Turks are enemies. A representative of the Independent Kurdistan movement even apologized for all Kurdish involvement in the Armenian genocide.
 * The best part is that the atrocities were done mainly by ethnic Kurds, not ethnic Turks. Which makes sense, since they live next to each other.
 * Combine this trope with Ape Shall Never Kill Ape and you get the basic idea for The Crusades.
 * During the 1800 election in the United States, Alexander Hamilton and Thomas Jefferson both decided that they hated Aaron Burr more than they hated each other, thus leading to Alexander Hamilton persuading the Electoral College to vote for Jefferson instead of Burr.
 * Similarly in 1824, John Quincy Adams and Henry Clay against Andrew Jackson.
 * Astonishingly common in US political history, compared to other countries. In fact, both main parties were this during a great deal of their history. To make things further complicated, there often have been alliances between members of opposite parties, which sometimes lead to political realignments. Indeed, both the Whig and the Republican parties were in large part formed by different interests that teamed up in opposition to the policies of the Democratic governments of the day.
 * Automotive example: Holden and Toyota teamed up to produce the Holden Commodore VR and the Toyota Lexcen. However, the Lexcen was not a export model, but solely an Australian version of the Commodore, but without the Commodore's big, brash, American V8 engine, instead only getting a Buick V6 engine. This was created so Toyota had a rival for the Ford Falcon (apparently the 1991-1995 Toyota Camry, incidentally, this was sold as a Holden too, the Holden Apollo being roughly the same size as a BMW 3-Series), a big car, and one of the Asia-Pacific region's biggest sellers. Needless to say, General Motors' (owners of Holden) alliance with Toyota ceased in 2005.
 * In 2006, Nigerian President Olusegun Obasanjo tried to change the constitution to allow himself to contest for a third term in office the next year. This led to a feud with his Vice President (and heir-apparent) Atiku Abubakar. To stop the amendment, Atiku teamed up with opposition leader Muhamadu Buhari who was planning a presidential bid as well. They successfully kept Obasanjo out of the race, but their alliance fell apart soon after since neither would step aside for/endorse the other. Obasanjo's new hand-picked successor, Yar'Adua, won.
 * In a more martial Nigerian example, imprisoned Niger Delta rebels like Isaac Boro were released by the government and admitted into the Federal Army to help thwart the Biafran secession. The Niger Deltans figured being minority ethnicities in a Nigeria with 3 mutually hostile major tribes was more palatable than being minority ethnicities in a Biafra with 1 very dominant tribe, the Ibo.
 * This trope has reoccurred on a regular basis throughout Canadian history:
 * Confederation itself was begun when the Reformer George Brown offered to serve in a coalition government with the Conservative John A. Macdonald to resolve the political gridlock that had paralyzed the United Province of Canada. Their efforts to solve the problem eventually led to the Confederation agreement that founded Canada.
 * The colony of Nova Scotia was bitterly divided over whether to join Confederation or not. The question was eventually resolved when the Irish nationalist Fenians, who were trying to gain political leverage with Great Britain by attacking Canada, began raiding the colony from the United States. The pro- and anti-Confederation movements were forced to team up and eventually joined Canada in no small part due to the need for mutual defence against any American raids.
 * On the other side of the continent, British Columbia had to deal with the same question. Along with a pro-Confederation movement, the province also had an anti-Confederation movement that wanted to stay independent and an Annexation movement that wanted to join the U.S. As in Nova Scotia, the pro- and anti-Confederates eventually came together.
 * During World War I, Canada was extremely bitterly divided over the issue of conscripting men to fight in the war, to say nothing of even participating in the first place. Prime Minister Robert Borden eventually overcame the Liberal opposition by enticing a number of Liberals to join him in a "Union" government that was a glorified coalition, leaving Wilfrid Laurier with a weakened Liberal rump based mostly in Quebec. Laurier's death in 1917 further crippled the Liberals' attempts to recover.
 * In the constitutional debates of the early 1980s, the Quebec separatist Premier Rene Levesque found common cause with seven of the other nine provincial premiers, who came together in opposition to Prime Minister Pierre Trudeau's constitutional reforms. The "Gang of Eight", as it was called, eventually forced Trudeau to put together a compromise that addressed some of their major concerns and eventually became the 1982 constitutional patriation.
 * The British General Election of 2010 brought about a coalition government of the right wing Conservative Party and the left wing Liberal Democrats.
 * Not so odd if you know a bit more about both parties. The Liberal Democrat free-marketeers (which Clegg represents) and the Conservative liberals (which Cameron represents) have more in common than difference. What has caused problems is that the broader parties don't get on and, given how the middle-class Labour support shifted to the Liberal Democrats during the 2000s, Clegg essentially gambled and is now losing much of his party's newer supporters (and doubtless some of the older ones).
 * This happens a lot on Internet debates about religion. Christian fundamentalists, atheists, and New Agers are all opposed to each other, yet in debates on religion, either the atheists will team up with the New Agers against the Christians, (as they think that fundamentalist Christianity is irrational) or the Christians will team up with the New Agers against the atheists (because they believe that atheists are against spirituality). For some reason, the Christians and atheists never team up against the New Age movement...
 * The reason, arguably, is that Christians are, generally, fairly ambivalent towards the New Age movement because seems fairly non-threatening and borrows from Christianity (angels, etc), and, while atheists are generally against spirituality, they may feel they have common ground with the new-age movement as its practitioners are also a minority, something that can lead them to see the New Agers as allies, or, at least, as people less opposed to their ideology than mainstream Christianity, which a lot of them kinda hate in a big way.
 * There is room for a Christian-Atheist alliance against new-agers. Both believe in a rule-following, relatively objective universe. But this alliance is very rarely seen.
 * The Westboro Baptist Church, aka the "God hates Fags" church, headed by 'Reverend' Fred Phelps, has managed to bring people with differing views together. This isn't difficult seeing as they've managed to piss off absolutely everyone. Most notably they've managed to unite leftists and rightists against them. Leftists oppose the church due to its extreme anti-homosexuality stance. Rightists are angry at them for their habit of holding protests at the funerals of US troops killed in Iraq and Afghanistan, where they hold picket signs bearing messages such as "God killed your sons", "Thank God for IED's", and "Thank God for dead soldiers".
 * The leftists aren't too pleased about those signs praising the deaths of soldiers either. Even the strongest anti-war activists usually don't want soldiers to die. Which makes sense because most antiwar people consider it a waste of valuable human life.
 * All the Christians who are against them, many because they aren't against gays, but there are even quite a few staunchly anti-gay people who, contrary to popular belief, generally don't want gays to be harmed - they just want them to not be gay. The Catholic Church may be against gay sex (they aren't against actual gays, just the sex) but they also run clinics for AIDs sufferers (and sex workers) in countries that want to string gays up by the neck, as well as offering support etc, spoke out on the Ugandan kill-the-gays law, and the Pope, himself, has said gay sex-workers should use condoms for their own protection.
 * National Voluntary Organizations Active in Disaster is a group of a number of organizations that are active in various facets of disaster response. The catch? Many are religious organizations from varying theological perspectives. Catholics respond alongside Protestants. Jews respond with Muslims. So do Hindus, Buddhists and the Scientologists. And- miraculously- it all works out! http://www.nvoad.org/
 * The alliance between the Kingdom of France and the Sublime Ottoman Porte; it was one of the first major alliances between a Christian and a Muslim state, directed against the Habsburg Empire.
 * And then again between Catholic France and Protestant Sweden during the Thirty Years War; once again to limit the Habsburg power. Cardinal Richelieu practically invented realpolitik. Sweden also was for a short time allied with its Arch Enemy Denmark-Norway during the war...but then Denmark-Norway allied with the Habsburgs in the late part of the war.
 * You might not expect Republicans like Ron Paul and the Tea Party movement to have common cause with progressive Democrats, but they've found themselves on the same side in opposition to free trade deals and continental integration. The Tea Party and its supporters see these trade deals as a threat to the sovereignty of the United States and government interference in international trade (many Tea Partiers would prefer to simply have no rules or regulations on trade at all), while their progressive allies see the trade deals as leading to jobs being offshored and labour standards being weakened in America itself.
 * The sovereignty issue is a sticking point for many left-wing nationalists in Canada as well. The progressive Council of Canadians has found itself on the same side as right-wing border groups like the American Minutemen, both of whom see continental integration as a threat to their countries' sovereignty.
 * Ron Paul and a number of Tea Partiers have also found common ground with the left-wing Occupy Wall Street, particularly over corporate welfare, Wall Street bailouts, foreign wars, and marijuana legalization.
 * The American Revolution was a classic example of this. The revolutionary republican American forces were assisted (arguably decisively) by troops and naval power supplied by France, at the time a very conservative near-absolute monarchy. It was deeply ironic when radical republican ideology crossed the Atlantic a couple of decades later and overthrew that same monarchy.
 * Napoleon's regime is an example of this in an ideology. Napoleon was a veteran of the French Republic's military, his government used the republican flag and he claimed to embody the ideals the republic had represented and yet his government was unashamedly an absolute monarchy with Napoleon not shirking even slightly from the trappings of royalism (see, for example, the painting of his coronation).
 * This trope is one of the reasons Drill Sergeant Nasty exists. Even if 40 people in a platoon can't agree on ANYTHING else, they can always unite around the fact that the sergeant's an ass.
 * In street demonstrations against Israel, the crowd will often include fundamentalist Muslims, anarchists, neo-Nazis, and anti-Zionist Hassidic Jews who believe the Messiah must come before Jews return to Israel.
 * Ronald Reagan seemed to be a fan of this trope, and in fact saw it as a potential avenue toward world peace. He once made a speech in which he wondered how much better the world would be if space aliens invaded, thus forcing the US and the Soviet Union to put aside their differences and fight the threat together. He felt this would remind both sides of their shared humanity, and lead to an end to human conflict. Lest you think he was joking, he actually brought up this scenario in several speeches, including one to the general assembly of the United Nations.
 * Slayer, bane of Religious Conservatives everywhere (at least in the 80's), released a pro-life song.
 * Another great example from history is the Catholics and the Protestants for teaming up against the Anabaptists. In the end the took back the city of Munster and then called it a day for their alliance and begin to promptly fight one another again.
 * American Censorship Day had a bit of this. In particular, groups like Wikipedia, Mozilla, Reddit, and Google were fighting alongside 4chan for a common cause (though this may be more of a Rivals Team Up; nobody particularly likes 4chan, but there's little actual hostility from the mentioned groups). Republican Darrell Issa also posted a tweet noting how both he and Democrat Nancy Pelosi were against SOPA.
 * The sites blacked out on that day also ranged from Bill O'Reilly's to Move On.org.
 * George Takei recently attempted to reconcile the feud between Star Trek and Star Wars Fan Boys by encouraging them to unite against a greater evil -- Twilight and it's fans.
 * This actually happens quite a bit in music. Some genres (such as Heavy Metal and Rap) will have people who believe that they should put aside all differences and unite against other types such as Pop. Don't believe me? Look on any YouTube music video not relating to Pop music.
 * Prominent religious conservatives and liberal disability rights groups have teamed up several times to fight the legalization of assisted suicide. They were also on the same side during the Terri Schiavo debacle.
 * Following the passage of Proposition 8 (which outlawed same-sex marriage in California), Several families sued the state on the grounds that the referendum was unconstitutional. The attorneys who teamed up to represent them in court were Theodore Olsen and David Boies, best known for arguing opposing sides of Bush v. Gore. Needless to say, the Defendants didn't stand a chance.
 * Electronic Arts essentially has made this happen indirectly for rival gaming communities, as 4chan, Reddit, Kotaku, and others helped them get declared 2012's Worst Company in America by The Consumerist.
 * The pro-life movement includes numerous groups arguing from different angles, many of whom wouldn't usually agree with the religious conservatives traditionally associated with the movement. Staunch atheists, self-styled liberals, American Democrats and feminists of various kinds have all been known to team up with them.