Ultimate Showdown of Ultimate Destiny

""Can a lightsaber cut through Superman?""

- Google autocomplete (There's also "Can a lightsaber cut through adamantium?")

Ah, the Intercontinuity Crossover fight. One of those things that makes you glad to be a fan. And even more glad that you're not that fan.

It's a recurring obsession of fans, the question of "Who would win in a fight?". Fans will reason it out, argue it out, come up with incredibly thorough theories about how and why and where, and eventually resort to name-calling and comparing their opponents to Nazis.

Of course, the occasional "smart" fan will interject that it's really not very likely that something would compel the two to fight against each other, as they're both heroes; or a fan will analyze the matchup in a relatively unbiased way, coming up with a result more steeped in common sense than "one is better than the other"; or someone will point out that the question is impossible to answer objectively since neither character's abilities are defined in-story in any quantifiable manner. Fans like these are usually ignored.

Occasionally, there will be a handicap or caveat, such as evening up a major difference in size, to make the fight fair.

Though both genders do both, speculation in this area can be thought of as, or at least akin to, the Spear Counterpart of Shipping.

Other similar debates include:
 * Out of Time, Out of Place: Taking a character or group from one series (say, the Fantastic Four), placing them in the setting of another series (say, Star Trek), and discuss what happens.
 * Force Substitution: A variation where a character is placed in a battle or scenario from another series—say, the defense of Minas Tirith.
 * Curbstomp: Similar to the original kind, only the thread creator, and most likely the general population of the board, knows full well (or at least believes) that one side has an overwhelming advantage. The purpose of this discussion is just how badly the underdog (who is usually considered unpopular, often to The Scrappy level, on that board) is going to get slaughtered.

The trope is named for the song and flash animation "The Ultimate Showdown of Ultimate Destiny" by Lemon Demon, in which nearly every famous fictional character, pop culture icon and historical personage ever come together for the sole purpose of knocking the living crap out of each other.

The geek-centric Wizard Magazine has a section devoted to this called "Who Would Win?" and would describe the stats of the two combatants and then tell the "real" fight that occurs. They then proclaim a winner and have a URL to go to to talk about it. They've done The Avengers versus the Justice League, Classic Wolverine versus Ultimate Wolverine , and Goku versus Superman. Anime Insider in America also runs a monthly segment in which two anime or game characters duke it out in fanfic format.

Usually settled with Popularity Power. See also Fan Wank and Evasive Fight Thread Episode. If it's actually canon then it's a Massive Multiplayer Crossover. Compare Character Tiers. Contrast Story-Breaker Team-Up. If you were looking for the song, go here.

TV

 * MTV's Celebrity Deathmatch is a Claymation version of Exactly What It Says on the Tin. Matches have included David Duchovny and Gillian Anderson vs. Tommy Lee Jones and Will Smith; Bono vs. Fabio vs. Yoko Ono; Bette Midler vs. Cher; and Adam West vs. Christian Bale.
 * Spike Tv's Deadliest Warrior, which explores "history's greatest killing machines", look at their historic backgrounds and the science behind their equipment and fighting styles, and pair them off in a one-on-one computer simulated fight. Showdowns include "Gladiator vs. Apache", "Ninja vs. Spartan", "Taliban vs. IRA", "Yakuza vs. Mafia", and "William Wallace vs. Shaka Zulu".
 * History Channel's Jurassic Fight Club, similar to Deadliest Warrior in that it uses best available knowledge to establish the abilities, strengths, and weaknesses of the animals, then CGIs the actual fights. Match-ups include Allosaurus vs. Ceratosaurus; Mega-Lion vs. the Short-Faced Bear; and Megalodon vs. Brygmophyseter, the "biting sperm whale".
 * Animal Planet had a short lived series Animal Face Off, which was basically Jurassic Fight Club done with living species that plausibly might confront one another in the wild.

Web Original

 * The Screamsheet has done weekly fights between a variety of characters since 2000. The fights have a loose continuity and several running jokes, such as Superman always losing and the Earth being destroyed multiple times.
 * The Comic Book Universe Battles, which started in 1997 as a sub-section of a Xena: Warrior Princess fan's Callisto fansite and eventually grew into something all its own.
 * The now-defunct WWWF: Grudge Match, though the archives are still there, listing the more than 200 fights the site has run.
 * The Lonely Winds forum has three sub-forums dedicated to various USoUDs in eight different leagues of various power level and compositions.
 * Numerous websites dedicated solely to what faction from Star Wars and Star Trek would lay the ultimate smackdown upon all the others. StarDestroyer.net is a particularly (in)famous one, and SpaceBattles.com caters to all kinds of sci-fi matchups but is invariably dominated by Trek vs. Wars as well as the occasional just-for-fun curbstomp (the Orcs from The Lord of the Rings vs. modern machine guns, carpet bombing from B-52s, an orbiting Imperial Star Destroyer, and finally, the real kicker, doze udda Orkz). Both of these websites more or less grew out of the Usenet newsgroup alt.startrek.vs.starwars.
 * "Dream Tournament", a popular series of vote-driven fanfics on the Usenet group rec.games.video.arcade from the mid-'90s, pitted Fighting Game characters from different games against each other. The Tournament gave rise to several spinoffs, as well as many Fanon personality traits for the characters.
 * There was an old fanfiction Dream Tournament called the Ultimate Video Rumble, where some truly memorable fights happened both within and without the arena. Highlights include Haohmaru and Genjuro of Samurai Shodown fame clashing swords furiously, while everyone who attempts to break their battle gets tossed aside, and dysfunctional organizers and security staff who make Eddy Gordo of Tekken fame suffer after he got eliminated from the ring.
 * The UVR was a deliberate spiritual successor to the first three Dream Tournaments, continuing many of the fanon events and characterizations from the DT.
 * Stefan "Twoflower" Gagne organized a Round Robin tournament featuring characters from all over anime (and sometimes, beyond) called Magical Troubleshooting Crossover Fighting Federation ULTRA. The various writers used and abused pretty much the entire Professional Wrestling trope list, with backstage plots ranging from mere personal power grabs and Mind Control to Third Impact and wresting Godhood from Kasumi Tendo Herself.
 * The golden rule staving off the inevitable fanboy flame wars was understood to read, "Anyone, under the right circumstances, can defeat anyone else in a fight." The only systemic exceptions to this idea were made to account for anime-style "weight restrictions."
 * It's worth noting that the story of how Kasumi became God and several other plot points such as Dark Sakura originated from MTCFF Beta which was a single-elimination tournament decided by votes rather than by individual authors, with such oddities as Fusion character "Nario" resulting from Naru of Battle Arena Toshinden and Mario of Super Mario Brothers tying in votes.
 * Ultimate Showdown tournaments are a common occurrence on GameFAQs' "Board 8", allowing users to debate to the most extremely geekish limits possible about who'd win. The arguing can lead to some, hmmmm, very curious victories (Apparently, The Mask can just barely beat Broly with cartoon physics, the most powerful Darkstalkers can win left and right merely based on their vague backstories alone, Voldemort can upset Nanoha's constant nuking of areas and people and the Doctor can defeat the Flash with, uhhh, timey wimey stuff. Or prep time. Or whatever).
 * History nerds are somewhat fond of debating Alexander the Great vs Genghis Khan. This battle actually happens in Arthur C. Clarke and Stephen Baxter's collabaorative novel, Time's Eye.
 * The RPG Duelling League is a site dedicating to deciding which Video Game RPG characters would win in a fight. The site is organized into 6 week long elimination tournaments (refered to as seasons) with four different Character Tiers (Light, Middle, Heavy, and Godlike). The voters who decide who wins are also strongly encouraged NOT to vote according to popularity or plot powers, but rather comparative in-battle capabilities and performance.
 * "Hitler continued laughing, then finally said 'Goku! You came here expecting to find a madman, but instead, you found a GOD!' Hitler had become a Super Saiyan." How's that for a Crack Fic-style showdown? See it right here in all its Not Safe For Sanity glory. By the way, it also ships Goku x Anne Frank.
 * Whosthebitch.com was the HQ for a fun and easy game; simply match any two given personalities (or even inanimate objects) and answer the question, "Who's the bitch?" Basically pick which one would be the 'bottom' in a relationship between the two, and justify your answer with an explanation.
 * Dead Fantasy shows what happens when a bunch of girls from the Final Fantasy series go up against a bunch of girls from the Dead or Alive series.
 * Sites like Comic Book Resources and Hero Chat have their own (Comic Book Rumbles and It's Clobberin' Time!, respectively), among many, many other websites. They often don't like each other. Most infamous incident was a flame war and board raid between Rumbles and Star Destroyer, after Rumbles determined Borg Cubes can destroy the Death Star. Cue Fan Wank and board raid.
 * The Crossover Wars of 2007. Loads of Web Comics against each other.
 * Related: OCT's (Original Character Tournaments). Players write/comic/animate their character winning against their opponent's character and the winner goes on to the next round. Since some of these characters come from established webcomics (or other internet media), fans might actually get a dream match...
 * Epic Rap Battles of History does this, but with rapping.
 * Sturgeon's Law is in full effect for this trope as well, as seen here. The maker of this blog constantly sets up 'fights', only to choose his favorite anime character and have them win the fight with no real explanation and no acknowledgement of the other character's abilities.
 * Factpile mostly runs on this trope. It has branched out to include other topics, but is still mostly battles between fictional characters. It has also determined the outcome of the page image
 * Make Your Move applies this to Super Smash Bros. with movesets for everything from King K. Rool to Socrates.
 * Screwattack's Death Battle sets characters up against each other as well, from Boba Fett vs. Samus Aran to Mike Haggar vs. Zangief to Starscream vs. Rainbow Dash. Notably not decided by votes, but by a look at each side's actual capabilities and extrapolating based on that.
 * This is what the Outskirts Battle Dome is for.
 * The Deadliest Fiction Wiki is basically this, using the formula from Deadliest Warrior, but for warriors of any media and franchise, with the warriors chosen by logical (usually) debates from the members of the site. It's essentially The Wiki Rule for Ultimate Showdown of Ultimate Destiny.

The concept used as one-shot

 * Harry Hill's TV Burp: "Well, I like X, but then I also like Y. But which is better?" [Costumed/made-up/bewigged representations/impersonators of X and Y crash into studio from opposite directions and make a beeline for each other] "FIIIIIIIIIIIGHT!!"
 * Will It Blend: Anything, at all, versus a Blend-Tec blender.
 * Anachronism: A card game that lets you pit various historical (or somewhat historical, like Robin Hood) characters against each other. For more fun, trade the character's goodies around—give Achilles Beowulf's chain mail and Miyamoto's katana.
 * Another card game Who Would Win?, which is Exactly What It Says on the Tin. Two players each get a random character, and then an event. Argue why your character would win. Santa Claus vs. Genghis Khan in synchronized swimming? Babar vs. Einstein in ping pong?
 * Mega Shark vs. Giant Octopus.
 * ... Vs. R. Lee Ermey.
 * Scribblenauts, which allows for a nearly infinite number of these. Bigfoot versus Longcat, God + Shotgun + Skateboard versus Cthulhu, T. Rex versus Robot Zombies... The fourth video found here takes this to absurd lengths.
 * The web site WWWF Grudge Match.
 * The comic book universe battles, who WWWF users saw as a friendly rival.
 * the Race Of Champions (ROC), an annual event which involves taking the best racing drivers from their repsective fields and different nationalities, putting two of them into 100% indentical cars and having them race head to head on a very short twisty track for 2 laps.
 * The Spoony Experiment had Deadliest Character, a direct take-off of the aforementioned Deadliest Warrior, featuring the Megazord vs. MechaGodzilla..
 * Tales From the Pit exposes "Who Would Win" as a favorite conversational topic of the Magic: The Gathering R&D team. Pairings include RoboCop vs. The Terminator and My Little Pony vs. the Transformers.
 * The children's book "Shark vs. Train", which takes the more common sense approach, with hilarious results (it matters, for instance, whether the competition is under water, or involves trying to sell lemonade.)
 * This is the main idea behind Defense of the Ancients: Allstars, which took heros and items from every other DotA version available at the time.
 * In 1953's Jungle Drums, a wilderness-adventure film crew stages a fight between a tiger and a lion.
 * The entire gag underlying Bambi Meets Godzilla.
 * The Galactic Watercooler podcast has a recurring feature called Fantasy Sci-Fi League in which participants choose teams based on specific roles (warrior, pilot, reconnoissance, etc) and place them in a scenario such as the rescue of one of the podcasters from a Klingon prison planet, and give them some basic equipment (such as Carl Sagan's Starship of the Imagination). The winner is chosen based on the most entertaining way of completing a mission.
 * The Buffy the Vampire Slayer episode "Buffy vs. Dracula". Right there in the title. The outcome, however, is indecisive, Buffy is unable to slay Dracula, but she does shoo him out of Sunnydale. Dracula's later appearances in the series range from Friendly Enemy to uneasy ally.

Happens In-Universe
This level of geekery can creep in, either as a crowd-pleaser or as a subtle way to insult your own fandom:

""Who would win, the Death Star or the Enterprise?" "Ditka!""
 * Batman and Dracula: Red Rain finally put to rest an age-old debate: The Dark Knight or the Prince of Darkness? Dracula and Batman fight over Gotham City to find out who the true master of fear and deception is.
 * Similarly, The Batman vs. Dracula.
 * Dracula vs. Superman also happened. By hypnotizing Lois Dracula actually gained the upper hand and succeeded in drinking Superman's blood (Assume that as a magical creature Superman is vulnerable to that). However, Superman is solar powered, and seconds after drinking his blood well... imagine eating a grenade.
 * Which is technically inaccurate, since Stoker's Dracula wasn't destroyed by sunlight, just weakened.
 * The most blatant example here is DC vs. Marvel/Marvel vs. DC (depending on who produced the particular issue you have). The crossover was built around five such classic face-offs (Superman vs. Hulk, Wonder Woman vs. Storm, Spider-Man vs. Superboy, Batman vs. Captain America (comics), and Wolverine vs. Lobo), and fans were invited to vote on the results, along with six others that didn't feature voting.
 * One of the best was JLA/Avengers, written by Kurt Busiek. Highlights include:
 * Superman and Captain America (comics) getting into a shouting match as the two teams face off, ended when Thor got mad enough to give Superman a face full of magic hammer.
 * Batman and Captain America facing off until they realize that they're equally matched and that someone is pulling both teams' chains. Then they leave to find out who. At this point you realize there's nothing the Big Bad can do, as he's screwed.
 * Writers are notoriously loathe to decide the Batman vs. Captain America contest. Not only here, but in the Batman/Captain America crossover by John Byrne, the two team up instead of fight. (They were also the 1940s incarnations of the respective characters.) And in the aforementioned DC vs. Marvel, they're about to team up again when Cap is temporarily immobilized by a river of sewage, giving Batman a technical victory.
 * A scavenger hunt for multiple Cosmic Keystones from both worlds, with everyone who has ever been on either team's roster participating as part of a Xanatos Gambit by the Grandmaster.
 * Superman barely defeating Thor in personal combat—severely wounded and almost in shock about how Thor "might have been the strongest I've ever faced" and "could have defeated me"—only to be beaten senseless by the rest of the enraged Avengers.
 * The latest one in comic books is Avengers vs. X-Men. There's even a tie-in miniseries devoted purely to one-on-one, "Who would win?" matches.
 * The Doctor Who original series episode "The Mind Robber" eventually, through convoluted means, features a sword fight that involved Cyrano de Bergerac, D'Artagnan, Blackbeard, and Sir Lancelot.
 * And "Doomsday" brings the fight people had been wanting for decades; Daleks vs Cybermen.
 * The novel "All-Consuming Fire" had Sherlock Holmes and the seventh Doctor square off with the Cthulhu Mythos.
 * This is arguably one of the purposes of such Massive Multiplayer Crossover Fighting Games such as just about every single Capcom crossover game ever and Super Smash Bros.. Super Robot Wars, despite being a Turn-Based Strategy game, also fits here.
 * MUGEN is a custom Fighting Game system which allows characters from different fighting games to battle aginast each other. It's gotten popular on YouTube, especially Perfect Cell vs. Dio Brando, where Dio wins using his famous steam roller attack.
 * Now that Super Smash Bros. Brawl has come out, players can decide Mario vs. Sonic for themselves. Mario and Sonic at the Olympic Games also takes this on.
 * Recently the Transformers franchise came up with a fighting game called Transformers Battle Universe wherein multiple versions of Optimus, Megatron, Bumbelbee... and one Starscream duke it out.
 * Dissidia Final Fantasy does this for the various heroes and villains of multiple Final Fantasy titles. Cloud vs. Zidane, Cecil vs. Tidus, Sephiroth vs. Kefka, Jecht vs. Kuja... the possibilities abound.
 * Spoofed in a recurring Saturday Night Live sketch in which George Wendt leads a cadre of football fans who speculate on the scores of hypothetical games pitting the Chicago Bears against other teams, with the Bears facing increasingly unlikely handicaps, such as being shrunk to the size of midgets. (Hint: Da Bears win.)
 * The punch line would often be some sort of fan-geeky paradox the even the "superfans" couldn't resolve. "Who would win, Da Bears or a hurricane?" "What if the Hurricane was named "Ditka"?" "Who would win, Da Bears or Da Bulls?"
 * As a result, for quite some time it was a Usenet in-joke (like an Internet Meme only ten years earlier) for someone to interject "Ditka!" into any who-would-win thread in the Usenet discussion groups. (Sort of like a lamer version of Godwin's Law.)

tle ends in a draw with only Superman and Raiden left standing, but the storyline does feature DC characters winning more fights than MK characters, due to their side of the story being a chapter longer. Perhaps most notable is a scene where a weakened Captain Marvel is able to defeat Scorpion, Baraka, and Shang Tsung in quick succession. "Wesley: Ah. You've been yelling at each other for 40 minutes about this? ...do the astronauts have weapons? Angel and Spike (in unision): NO!"
 * There was an old Disney cartoon in which a little boy and his grandfather tune into a fantasy match between an old-style football team from the days of leather helmets and a modern day style team.
 * And now, because you can find anything on the Internet, there are sites that exist to simulate this exact sort of game, for instance What If Sports.
 * The Toronto Maple Leafs Vs the Swedish Olympic team. Mats Sundin is on both teams.
 * Alternatively, The Detroit Red Wings vs. the Swedish Olympic team. Almost half the roster is the same.
 * Kristofer Straub, the author of Starslip Crisis, has challenged all sci-fi Web Comics to enter their respective ships in The Alterverse War, where they will battle each other.
 * Sadly, the series went into hiatus shortly after it began. The only battle we saw was the Fuseli vs. the Touch and Go.
 * Despite some fora now trying to crack down on the "X vs. Y -- who would win?" threads, they're impossible to avoid on Yu-Gi-Oh! and GX sites. The common opponents are of course Yugi vs. Judai, Mai vs. Asuka, and Kaiba vs. Kaiser.
 * Of course, GX tried to satisfy that first one with Judai dueling against Yugi's deck (stolen by a fellow student adept at copying other duelists), and barely won. However, it was pointed out that, since this was just an imitator, it doesn't necessarily make him better.
 * The Mai-Otome manga put the Otome against the HiME, or, more specifically, their resurrected My-HiME counterparts. Guess which side won.
 * One of the odder comic book examples: Superman vs. Muhammad Ali
 * You don't know the half of it. I provide for your amusement: Santa Claus vs The Incredible Hulk and Santa Claus vs the Iron Man When you see Cringle pull out a submachine gun on the Man O' Iron, you know that Ho-Ho-Homicide is about to happen. As for pulling a crowbar out on the Hulk....
 * Movies like Alien Vs. Predator, King Kong vs. Godzilla, and Freddy vs. Jason cater to this. The latter, interestingly, was originally going to be called Freddy vs. Jason vs. Ash, but Sam Raimi wouldn't let them use his character unless he won, and the makers didn't want too clear-cut a victor. In the end, Raimi approved of a comic version of the story.
 * One review of Alien vs. Predator opened by mentioning the latter two "vs." movies, then, struggling for a third example, adding, "and... um... Lassie vs. Flipper?"
 * It should be noted that there were several Aliens vs. Predator games and comics long before the movie was even thought of.
 * And then there's the Alien vs. Predator vs. The Terminator comics.
 * Note that when previews of Predator first came out, some critics joked about how Hollywood had run out of other opponents for Arnold to fight, so now they were pitting him against E.T....
 * Memorable curbstomp: the short film Bambi meets Godzilla.
 * Memorable reversal: the short film Son of Bambi vs. Godzilla.
 * How about Godzilla vs. Charles Barkley.
 * Via Actor Allusion, a battle between two famous hotblooded Super Robot pilots, Domon Kasshu and Gai Shishio, almost happens in an episode of They Are My Noble Masters. No conclusion is reached. Master Asia (also via Actor Allusion) kicks both of their asses. At once.
 * Koei released a game entitled Warriors Orochi, which amounts to a crossover between their (Three Kingdoms China) Dynasty Warriors and (Sengoku Japan) Samurai Warriors franchises. Much of the plot deals with this, such as Lu Bu's hunt for Samurai Warriors equivalent Honda.
 * And by the 3rd series, they also tossed in the bonafide Badass Video Game Ninja Ryu Hayabusa, as well as the bonafide Trojan Wars Badass Achilles.
 * Jet Li vs. Jackie Chan. Fortunately, we had The Forbidden Kingdom to answer this question for us. Unfortunately, it was a draw.
 * Jet Li has gone on record as saying that in a no holds barred fight, Jackie would wipe the floor with him.
 * The original series of Star Trek had an episode in which aliens set up an Ultimate Showdown: Kirk, Spock, Abraham Lincoln, and Surak versus Colonel Green, Kahless, Zora, and Genghis Khan.
 * As well in the movie Star Trek Generations, Kirk meets Picard. And the fans went nuts..
 * Mortal Kombat vs. DC Universe. The final epic bat* The Galactic Watercooler podcast has a recurring feature called Fantasy Sci-Fi League in which participants choose teams based on specific roles (warrior, pilot, reconnoissance, etc) and place them in a scenario such as the rescue of one of the podcasters from a Klingon prison planet, and give them some basic equipment (such as Carl Sagan's Starship of the Imagination). The winner is chosen based on the most entertaining way of completing a mission.
 * Mortal Kombat vs. DC Universe. The final epic bat* The Galactic Watercooler podcast has a recurring feature called Fantasy Sci-Fi League in which participants choose teams based on specific roles (warrior, pilot, reconnoissance, etc) and place them in a scenario such as the rescue of one of the podcasters from a Klingon prison planet, and give them some basic equipment (such as Carl Sagan's Starship of the Imagination). The winner is chosen based on the most entertaining way of completing a mission.
 * Generally agreed to be what makes Soul Calibur 3 and 4's Create-A-Soul feature so much fun.
 * In an episode of Angel, Wesley walks into Angel's office to discover that Angel and Spike have been arguing vehemently over who would win if astronauts and cavemen got into a fight. Unfortunately, the events of the episode prevent them from reaching a conclusion...although Whedon's general storytelling method and some dialogue in the episode hints on where his money, though not his heart, is: cavemen, i.e. humanity's barbarousness and savagery can and do defeat reason or higher ideals.

"Fred: Cavemen win, of course cavemen win."
 * And later Fred, delirious from the Elder God eating up her insides...

"" Many an argument did he have with the curate of his village (a learned man, and a graduate of Siguenza) as to which had been the better knight, Palmerin of England or Amadis of Gaul. Master Nicholas, the village barber, however, used to say that neither of them came up to the Knight of Phoebus, and that if there was any that could compare with him it was Don Galaor, the brother of Amadis of Gaul, because he had a spirit that was equal to every occasion, and was no finikin knight, nor lachrymose like his brother, while in the matter of valour he was not a whit behind him.""
 * Kamen Rider Decade does this for its own franchise. The plot requires the titular Rider to travel to Alternate Universe versions of the nine previous Kamen Rider series in order to stop a cataclysm of multiversal proportions. Thanks to his Power Copying ability, Decade can take on the form and powers of the last nine hero Riders, allowing matchups that couldn't happen even with the series' concept, such as Kuuga vs. Kiva, Kiva vs. Knight and so on. As the protagonist, Decade is naturally going to win, but apparently the staff thought that using Alternate Universe versions of these shows would allow fans to say "Decade can beat this new Kuuga, but the real Yuusuke would give him a run for his money." Didn't work.
 * After Super Sentai did their own Crisis Crossover with Kaizoku Sentai Gokaiger (with Decade's Power Copying but less Let's You and Him Fight), Toei one-upped themselves with Kamen Rider X Super Sentai Super Hero Taisen, pitting the Kamen Riders (led by Decade) against the Sentai warriors (led by GokaiRed). You can tell how this is going to go when a third faction, led by each franchise's current heroes (Kamen Rider Fourze and the Tokumei Sentai Gobusters), pops up and asks why they're even fighting in the first place.
 * Mobile Suit Gundam 00 made a nice set up of sorts in the 00 final:
 * Pretty much the premise of Heroscape. So far, the only copyrighted characters they have managed to aquire are from the Marvel Universe, but they've got enough obvious expies to make up for it.
 * 1906: Arsène Lupin vs. Sherlock Holmes, by Lupin's author Maurice Leblanc, as an Affectionate Parody. Soon afterwards, Arthur Conan Doyle complained and, from the following edition onwards, the story became Arsène Lupin vs. Herlock Sholmes (or, in some versions, "Holmlock Shears").
 * In actuality, Lupin was invented in the first place as a sort of French Sherlock Holmes Expy for a French imitation of the English magazine in which Holmes stories appeared. Leblanc introduced the "real" Sherlock Holmes and Watson in the spirit of the traditional English/French rivalry, mainly for the purpose of making them out to be doddering fools. (For instance, the renamed Watson, "Dr. Wilson", invariably gets badly injured every time he appears on-screen.) "Sholmes" appears in a number of Lupin stories, up to The Hollow Needle.
 * As both characters have fallen in the public domain now, Frogware released 2007 video-game Sherlock Holmes versus Arsène Lupin, known in some countries as Sherlock Holmes: Nemesis. Also, some recent translations of the original Lupin novels take the liberty of restoring Holmes's real name.
 * In a way, the Holmes vs. Lupin rivalry continues in the manga and anime Detective Conan. Conan is an Expy of Sherlock Holmes, while the Kaitou Kid is an Expy of Arsène Lupin. (Not to mention the Lupin III vs. Detective Conan Crossover TV special.)
 * This was the whole concept of King of Fighters. People from Fatal Fury fighting against Art of Fighting characters.
 * And Capcom vs. Whatever games.
 * Although it tends to get lost amid the alien warfare, Jake and Marco from Animorphs are huge fanboys and like to argue about whether Batman could beat Spider-Man.
 * Quake III Arena, where characters from almost all of the Id franchises (and many original ones) duke it out for supremacy. The list covers Doom, (with the Doomguy, and the new warriors Phobos and Crash) and the Quake games up to that point. (Ranger from the first game, accompanied by Wrack; and Bitterman, Grunt, Major, and a Tank, from the second game) Team Arena added a Wolfenstein-based character, Fritzkrieg, and it's rumoured that Sarge would be nothing the less than B.J. Blazkowicz.
 * Done in-verse with the NCIS team. They like to discuss Gibbs vs. all comers. They pretty much decide that the best fight would be Gibbs vs Gibbs.
 * In a short story from the Wolf & Raven anthology for Shadowrun, it's revealed that professional baseball in the Sixth World has become an exercise in this trope, with skillwired players' performance being dictated by software that makes them play exactly like historical star players. Thus, each season sees matchups like Babe Ruth vs. Mark McGuire, or even Babe Ruth from 1923 vs. Babe Ruth from 1927.
 * The Family Guy vs. American Dad web fighting game in promotion of the series' DVD releases; Ryu is the game's boss.
 * An episode of The Annoying Orange featured Liam the Leprechaun forcing the orange to see if he was more annoying than Fred.
 * Alonso Quijano and his friends the curate and the barber were victims of this phenomenon… Keep in mind this book was written more than four hundred years ago! At chapter I Part I we learn that:

"Willis: I'll get back to you on this."
 * Ip Man films are largely an excuse for  vs. Wing Chun duels.
 * In-Universe in Adventure Time, where a college for worms has a "Theoretical fightonomics" class. According to the professor, the winner is always.
 * In a Shortpacked Q&A, David Willis is asked "Who would win in a fight, Mike, Batman, or Jesus?" At first he answered "Well, Jesus refuses to fight, and Batman refuses to kill, so victory goes to Mike." But then he realized that killing Jesus is the way to activate his God Mode. And Batman is supposedly Catholic, so he'd be spared Jesus' wrath, so Mike loses. But then again, Mike doesn't particularly want to go to heaven...


 * 21 and 24 on The Venture Brothers often get into arguments about hypothetical fights such as Champ vs. Nessie or Lizzie Borden vs. Anne Frank.

Web Comics
"It's easy to go in a murderous rampage when your victims are mostly scared unarmed teens. But being a undead monster with a weapon isn't anything special in the Mortal Kombat universe. Hell, 1/3 of the current cast fit the description. If anything, people would giggle at Jason['s] crude "fatalities". Like a monkey with a brush trying to do art. No class, no finesse.. just senseless hacking. Meanwhile people are doing sculptures with their opponents guts, with them still alive and screaming."
 * Nerf Now occasionally does such things for laughs. Jason as a Guest Fighter in Mortal Kombat? Underwhelming.


 * Eight Bit Theater's Fourth Wall Mail Slot Twinkin' Out With Red Mage ran several columns dedicated to Red Mage answering "who would win" fights suggested by readers, starting Twinkin' Out 7: Superfight Spectacular. Reader suggestions ran the gambit anywhere from comic book heroes and villains to real life celebrities and historical figures, including Lincoln versus John Wilkes Booth and Gandhi versus Martin Luther King Jr. The feature concluded its 2004 run with a Superfight elimination tournament that pitted Wolverine against Link (the latter of which had just defeated a three-man team of Pyro, Superman, and God to reach the finals) in the final match which remains unconcluded five years later.
 * And don't forget the Flash animations featuring matchups between the webcomic's characters (removed from the official website, but still available here.
 * Also, once the comic spent two installments with RM and Black Mage discussing on who'd win, Batman or Doctor Doom, with BM finishing the argument with "Doom's machinations are such that even if Batman wins, his victory will somehow further Doom's villainous schemes". Another had the two discussing on Bullseye vs. Green Arrow, with BM arguing against precisely shooting several arrows at once - until he received it himself.

Web Original

 * Yu Gi Oh The Abridged Series: Littlekuriboh vs. KROOOOOOOOOOOZE.
 * The Brave and The Bold: The Lost Issues often sets Batman or The Thing against various characters.
 * Dark Horse Comics asked who would win; Dr McNinja, or Saxton Hale? At the time of this edit, votes are still being accepted. Each character asked fans to vote for them on their respective websites.