"What happens when an unstoppable force meets an immovable object?" is one of the most famous formulations of a Yin-Yang Clash in the Western consciousness. As a result, it's become a Stock Phrase for describing any conflict between particularly strong or particularly stubborn individuals.
Some people try to claim that the unstoppable force would just bounce off and continue moving, albeit in a different direction (according to Newton's third law of motion, and conservation of energy and momentum... you know: science). For this reason, the question is sometimes phrased using the term "irresistible force" instead.
A similar concept appears in Japanese and Chinese media: the term 矛盾, meaning "contradiction," is formed from the characters for "spear" and "shield." This is taken from a 3rd-century text that included a parable about a merchant who sold a spear that could pierce any shield, and a shield that could resist any spear; a customer pointed out the obvious contradiction, to which the merchant had no answer.
Please note: This article is about the actual phrase itself. If two really strong guys fight, and no one compares them to an immovable object and an unstoppable force at any point, then the example belongs in Ultimate Showdown of Ultimate Destiny or Yin-Yang Clash.
Unrelated to X Meets Y.
- In Aphorism, Nanto and Hokuto are twin brothers who have chosen the characters 'spear' and 'shield', respectively, and end up clashing in order to obtain the book of Life to resurrect their lost sister. This was a case of an Invoked Trope, though, because the one who prompted them to it was very well aware that their characters form the word for 'contradiction' together. Their battle isn't decided up until Momiji disguises himself as one of the brothers.
- In Pokémon, Rampardos is described as the unstoppable force/spear that can break any shield and Bastiodon is described as the immovable object/shield that can't be broken. They battle. So you might be wondering what happens when Roark's Rampardos battles his father Byron's Bastiodon. The answer? The battle is interrupted due to Team Rocket before it can be resolved.
- Alluded in Eyeshield 21, when Yamato (the original bearer of the title) and Shin (the antithesis of main character Sena) met, both are considered the unstoppable Runner and the strongest Linebacker respectively. The result is sort of definite though, with Yamato managed to drag Shin with all his strength...at snail pace. To say the watchers amazed is an understatement.
- In The Lucifer and Biscuit Hammer, Yukimachi and Subaru's paired attack and defense directly allude to this - they call their telekinetic attack "the Strongest Spear" and their telekinetic shield "the Ultimate Shield." They pick the names from a story shared by their teacher, the Master, about a spear that could penetrate any shield and a shield that could block any spear. In the hands of a single warrior, that warrior would be unstoppable. The Master then clasps their hands together, declaring the two together to be "the warrior."
- Referenced in the anime of Trigun by Hoppared the Gauntlet, who declares himself as an invincible shield and Vash's guns as an unstoppable spear.
- Discussed in Saint Seiya during Seiya's early fight with Shiryu and even referred to as such. In a twist, Shiryu's in possession of both: his shield too strong for Seiya to breach while his Cloth has a right gauntlet just as hard on top of his considerably greater raw strength. Seiya ultimately solves the conundrum by tricking Shiryu into attacking him in such a way that when he dodges, he ends up punching into his own shield. The shield breaks, but Shiryu also breaks the gauntlet and hurts his hand in the process and is forced to continue the fight without his Cloth.
- In Naruto, the legendary Third Raikage possesses an impregnable defense and indefensible offense through using his lightning chakra cloak.The only way he could be wounded was to turn his attacks on himself.
- According to Go Nagai, Shin Getter Robo is the unstoppable force while Mazinkaiser is the immovable object.
- In Katanagatari, the first of the Twelve Deviant Blades Zettou Kanna was supposed to be unbreakable. The second sword Zantou Namakura was supposed to be able to cut anything. When Shichika wondered what would happen if the swords clashed, Togame guessed that Zantou Namakura would prevail since it was forged later. Confirmed in the end, when Shichika's Kyotouryuu, the final perfected Deviant Blade, easily shatters Zettou Kanna.
- The Severing Crime Edge: Apparently the reason why the Crime Edge (an indestructible sharp pair of scissors that can cut anything) can cut Iwai's otherwise unseverable hair.
- According to director Mitsuo Fukuda, Mobile Suit Gundam SEED's Strike and Aegis Gundams were designed with the Eastern version of this paradox in mind: "What happens when a sword that can destroy anything hits an invincible shield?" Hence their Meaningful Names; "Strike" as in what a sword does, "Aegis" as in Athena's shield. The answer: they're both destroyed. Time for a Mid-Season Upgrade.
- Referenced several times in Jormungand using the Chinese style pike vs shield version. Willey details the original parable in one of Jonah's lessons while the opening song for the first anime season "Borderland" contains the phrase "pike and shield" in English as a short hand for idea in the lyrics.
- Discussed in The Rising of the Shield Hero: right before their duel, Motoyasu pointed out to Naofumi that, as the Spear Hero and the Shield Hero respectively, they were comparable to them... Before adding that Motoyasu's greater level (about twice Naofumi) and the Shield's lack of offensive abilities gave him the advantage. Motoyasu wins... By unknowingly cheating: Naofumi had made the same reasoning and carried a number of Orange Balloons (the most basic monster mooks) on himself because they couldn't harm him but could cause at least some harm to Motoyasu, and thanks to that and a number of creative uses of the Shield's abilities (including a counterattack one) gained the upper hand until Malty shot Naofumi with a wind spell in the back, allowing Motoyasu to pin Naofumi down and claim victory without realizing he had been helped.
- Incredible Hulk #272. Hulk and Sasquatch ram Wendigo using downed trees, with Wendigo in the middle◊.
The Wendigo becomes the immovable force between two irresistable objects.
- This phrase is more overused in The Hulk than anywhere else. Whenever the writers want
belaborto impress that an opponent is a serious physical challenge to Hulk, they will be one of these, and Hulk will be the other.
- This phrase is more overused in The Hulk than anywhere else. Whenever the writers want
- Invoked directly in the second Superman/Spider-Man crossover, when Superman calmed down The Hulk by planting himself to the ground and let the Hulk hit him, thinking that when he decided to become the Immovable Object, no Unstoppable Force could move him. He also hinted that he didn't want the Hulk to get any angrier, or he'd become more than even he could handle.
- Grant Morrison's All-Star Superman has Superman being asked this question. His solution? "They surrender." note Ironically enough, he seems to have gotten this from the back of a newspaper he read only a few moments before in the animated adaptation.
Ultra-Sphinx: Answer. Acceptable.
- When former X-Men writer Chuck Austen was asked in a interview; what would happen if the unstoppable Juggernaut runs into the immovable Blob? He replied...
"They'd pound on each other until they were both so exhausted that they'd just lay down and watch videos. Porn, of course!"
- The toy review site OAFE.net answered this question with a toy comic. Basically, they shake hands and say hi. (Which makes a lot of sense in-story: the Juggernaut and the Blob have both been members of the Brotherhood of Evil Mutants, although they are rarely on the team at the same time.)
- Marvel Super Heroes RPG, knowing its readers, provides an answer to this. "Juggernaut could move The Blob by destroying the ground underneath his feet, unless he was sitting on a planet made of Adamantium" (it didn't say what would happen in that case, however).
- One Expanded Universe novel had them fight each other. Juggernaut won, because Blob flinched before the impact. Marko internally noted that had Dukes not flinched, the collision would have been really painful.
- This has actually happened in comics; The Blob's status as "immovable" is more a badass boast on his part than an actual assessment of his powers; while he is extremely difficult to move, the Juggernaut, the Hulk, and Strong Guy have all successfully moved Blob through sheer force. In every case it's been via hitting him so hard that whatever surface he's planted himself on gets broken off from the rest of the ground.note
- Back in the Silver Age, Superman and Superboy tried to test this out by flying into each other. They wound up with memory loss and ripped the Time Stream a new one.
- Ultimate X-Men: There's a train taking Nick Fury, and Colossus gets in the railroad to stop it. But he does it under protest: there's a chance he may stop it, right, but also that the train would squash him like a bug.
- A Naruto-Justice League crossover had Sasuke's sword of Kusanagi vs. Wonder Woman and her gauntlets. The sword dented the gauntlets, shocking them both—Sasuke because it didn't cut through, Wonder Woman because it dented them at all.
- In the Discworld fic Nature Studies, Sam Vimes watches a showdown between a charging rhinoceros and Sergeant Detritus bracing to meet it head on. He reflects that Vetinari was banging on down at the palace about the old philosophical conundrum of what happens when the irresistible force meets the un-moveable object. He reflects the Patrician would give something of personal value to witness what happens next... and then the two met.
- In the Babylon 5 fic A Fighting Chance, a Minbari fleet charging a wall of EarthForce dreadnoughts who can see through their stealth is described as an irresistible force running in an immovable object. The Minbari almost broke through, but at that point the human ships fired thousands of missiles at them, annihilating their fleet.
- In Shinobi of the High Seas both Naruto and Lucci are surprised when a kunai imbued with wind chakra cuts the latters hand. Naruto because it didn't take his hand off; Lucci because it did any damage at all.
- The end of Naruto's and Lee's fight in Reaching for a Dream consists of Lee opening the Chakra Gates and pummeling Naruto who's forced to use a defensive technique that greatly reinforces his body but leaves him functionally immobile.
- In Blink, the Kyuubi tries to destroy the Shinigami's seal and learns what happens when an unstoppable force (himself) meets an immovable object (the seal): time stops until he stops trying. Because Naruto's immune to it, he gains the moniker of "Blink" because if you close your eyes, even to blink, when facing him they'll never open again.
- In the Pony POV Series:
- Celestia's brothers Turris and Leo are the Gods of Unbreakable Defense and Force/Breaking Barriers respectively. This means Turris can create barriers and shields nothing can pierce (not even the Concept Killing Spear, the single most dreaded weapon in existence) and Leo cannot be stopped once he gets going no matter what's in his path. While trying to stop Celestia from bringing the Windigos to Earth in a well intentioned but foolish attempt to remove hatred from existence, Leo accidentally runs into Turris's barrier. The end result is both are knocked silly with neither winning out.
- Princess Anasi, Trixie's Dark Future Alicorn self, is the Goddess of Trickery and Illusions, as such she can produce illusions nothing can pierce. Princess Veritas Applejack's potential Alicorn, is the Goddess of Honesty and can pierce any lie. While not shown, Anasi implies the same thing would happen as with Leo and Turris if their powers clashed against each other. However, Nightmare Mirror, due to not being a Concept and an incomplete version of Veritas, can't pierce Anasi's illusions and her truth vision simply doesn't work on her.
- A particularly literal example of this theory put into practice in the fanfic Dangerous Tenant, as ruthless and genetically-augmented megalomaniac Albert Wesker is thrown into the TARDIS as his base explodes, colliding with the central time rotor, the force of the impact knocking him out long enough for the Doctor to inject Wesker with a new virus that 'cures' Wesker of all his enhancements, while the TARDIS itself is undamaged by the impact.
- Explicitly quoted in the Buffy the Vampire Slayer/Heroes crossover Interventions, when the final battle pits Sylar against Xander, who has recently acquired the power of immutability; Sylar can knock Xander down and destroy his clothes, but he can hit Xander with everything from telekinetic force to poisonous gas and it wont actually stop him, although Xander freely acknowledges that he can't actually hurt Sylar in turn.
- Persephone: Gobber describes Stoick and Hiccups discourse as like setting two diamonds against one another; only they can make any meaningful impact onto one another and eventually one will break.
- The phrase is used by Funny Valentine to describe his feud with Johnny Joestar in Keeping Up With The Joestars. After Johnny lost 10k on the Steel Ball Run, but had no way of proving that it was actually a scam, he started dedicating his life to annoying Valentine, and succeeding.
Think of it as the immovable object vs unstoppable force analogy. Valentine was patient and perpetually calm while Johnny was a very irritating and resourceful kid.
- This Transformers fanfic gives this role to Autobot Prowl and Decepticon Jazz and their relationship is further explored in the sequel as well as this bonus oneshot.
- From The Dark Knight, after Batman knocks the Joker off a building and then fires his grappling cable to save his life:
The Joker: Oh, you. You just couldn't let me go, could you? This is what happens when an unstoppable force meets an immovable object. You are truly incorruptible, aren't you? Huh? You won't kill me out of some misplaced sense of self-righteousness. And I won't kill you because you're just too much fun. I think you and I are destined to do this forever.
- Imagine Me & You:
H: What happens when an unstoppable force meets an immovable object?Luce: It never happens. If there's a thing that can't be stopped, it's not possible for there to be something else which can't be moved, and vice versa. They can't both exist. You see? It's a trick question, is the answer.
Heck: I want you to be happy. More than anything else, I wanted to be the cause of happiness in you. But if I'm not, then I can't stand in the way. Do you see? Because what you're feeling now, Rachel, is the unstoppable force... which means that I've got to move.
- And later, when Heck has decided to leave Rachel because he knows that she's in love with Luce:
- The Avengers (2012): Thor's Hammer vs Captain America's Shield. The result? The force of the impact doesn't hurt Cap, but is instead reflected into a shockwave that levels all the forest in their vicinity. The phrase isn't used in the movie itself but in the wider MCU, Thor's movie called his hammer the ultimate weapon and Cap's movie called his shield the ultimate defense.
- A Russian joke runs like this:
Vovochka, what will happen if unstoppable force will affect unmovable object?Vodka price will rise?Why do you think so?'Cause my dad always says: First some weird crap happen — then vodka price will rise.
- A generic quip on the subject:
Q: What happens when the unstoppable force meets the immovable object?A: They have an indescribable accident.
Q: What happens when the unstoppable force meets the immovable object?
Q: What happens when the unstoppable force meets the immovable object?A: That would never happen, Chuck Norris would never kick himself in the face.
- Used as a riddle in the far-future section in Ian Banks' "Walking on Glass". The actual answer is randomly tossed out in the other narrative. The unstoppable force stops, the immovable object moves.
- Similarly, a Mensa puzzle book from 1991 uses this riddle as one of its logic puzzles. The answer is an impossible event. Logically, the existence of one disproves the existence of the other by definition, and therefore the two cannot exist at the same time, therefore such an event will never occur.
- Only two people in the world of Soon I Will Be Invincible have "Invincibility" listed as a power...
- The Dresden Files: Harry Dresden defines the mind games between him and Molly in this way. He has a big, obstinate castle (unmovable object) while her attacks are equivalent to several Mongolian Hordes (irresistible force). It usually ended in a draw and two headaches.
- In Rivers of London - Whispers Under Ground, after watching Zach chowing down on one of Molly's gigantic breakfasts, Peter quips about how the unstoppable cook is up against the unfillable stomach.
- The Saga of Arrow-Odd: When Odd and Hjalmar and the Arngrimssons prepare for single combat on the island of Samsø, Angantyr Arngrimsson wants to take on Odd, because Odd has a magic shirt that is supposed to be impenetrable to any weapon, and Angantyr has the magic sword Tyrfing that supposedly can cut anything in the world. However, Hjalmar insists that he take on Angantyr, and thus we will never know whether Tyrfing would have worked on Odd's shirt.
- In The Fountains of Paradise by Arthur C. Clarke a reporter uses this phrase to describe the conflict between ace engineer Vannevar Morgan, who wants to build a space elevator on a mountain, and the abbot of a Buddhist monastery that has been sitting on top of the mountain for thousands of years.
- In The Grimnoir Chronicles, the characters Jake (a 'Heavy' able to control gravity and alter his density) and Toru (a 'Brute' equipped with Super Strength) have this dynamic, though the spend most of their time as uneasy allies.
- In Mazeway by Jack Williamson, the main characters are repeatedly asked "What happens when the all-cutting blade meets the uncuttable stone?" The blade is sharpened.
- Referenced on one episode of M*A*S*H, when Hawkeye and B.J. go on a bathing strike in response to Charles' french horn. When Charles refuses to budge, Hawkeye prefaces their next gambit with: "That's it! The irresistible force is about to polish off the immovable object." What actually happens is the rest of the camp forcibly hose down Hawkeye and B.J. and then run over the french horn.
- That Mitchell and Webb Look's football promo sketch contains this (and the similar "The giants of Charlton play host to the titans of Ipswich, making them both seem normal-sized").
- Used in the Knight Rider episode "Trust Don't Rust", to describe the theoretical outcome of a head-on collision between KITT and KARR. They refer to it as "Zeno's Paradox".
- In an episode of The Adventures of Superboy, a professor asks Superboy to help transport an insanely heavy totem pole, referring to the pole as the immovable object and Superboy as the unstoppable force. The totem pole was so heavy that even Superboy had difficulty lifting it. The totem pole suddenly disappears as soon as it's completely out of its hole, releasing Mxyzptlk.
- In the Monkey episode "Monkey Swallows The Universe", the narrator states: "When what is indestructible meets what is irresistible, the female all to often wins."
- The Defenders (2017). When Iron Fist punches Luke Cage, the result is a Kung-Fu Sonic Boom that knocks down everyone in the area, including Luke and Danny.
- The old Johnny Mercer standard, here sung by Fred Astaire to Leslie Caron in 1955's Daddy Long-Legs:
When an irresistible force, such as you,Meets an old immovable object like me,You can bet just as sure as you live,Something's gotta give —Something's gotta give —Something's gotta give!
- Skyclad tells us in "You Lost My Memory" that
Unstoppable force and immovable object,repel one another when by chance colliding.
- Jane's Addiction's "Irresistible Force (Met the Immovable Object)".
- A Greek story has a variation with the Teumessian Fox (who can never be caught) and Laelaps (a hound that can never lose its prey). Naturally, they're set on each other. Zeus, unable to tolerate this kind of paradox, turns them to stone and casts them into the sky as the constellations Canis Major (the hound) and Canis Minor (the fox)..
- Similarly, the Nemean Lion had claws that could pierce any armor, and a hide which couldn't be pierced by any weapon. Heracles decided to strangle the lion to death, then cut its hide with its own claws to make a snazzy cloak.
- An old Chinese legend concerns a blacksmith who makes both shields and spears. He first pitches a customer the spears, claiming that they are so sharp, no shield can block them. He then pitches the shields, saying they are so hard, no spear can pierce them. The customer then asks what would happen if he threw one of the blacksmith's spears at one of his shields...and received no answer. This is the source of the Chinese word for "paradox;" "矛盾," or máodùn, literally translates as "spear-shield.''
- An oft-played clip from WrestleMania III's iconic Hulk Hogan vs André the Giant match is commentator Gorilla Monsoon calling the match, "The irresistible force meeting the immovable object."
- From Olde Wrestling Another Extravaganza Of Wrestling Exhibitions, September 28, 2014: A collision between Jock Samson and Jerk during the Moonshinin' Men of Appalachia-Jollyville Jeepers match where neither guy budged led to the commentator describing it as "The irresistible force meets the immovable object."
- In The Ballad of Edgardo, the irresistible force (Raw Spirit) beats the immovable object (invincibility defenses).
- The 1999 Jacksonville Jaguars won every game they played and were favored to win the Super Bowl...except they couldn't beat their divisional rival the Tennessee Titans. The Jaguars went 14-2 in the regular season with both losses being to the 13-3 Titans. They met for a third time that season in the Conference Championship, and again the Titans won, eliminating the Jaguars from the playoffs. For comparison sake, the Jaguars had scored 62 points in the previous game, but were held to just 14 against the Titans. The Titans would go on to lose the Super Bowl to the Rams.
- The phrase was in wide use referring to the 2013 Big Ten Football Championship game, which pitted the Ohio State Buckeyes against the Michigan State Spartans. Ohio State was known for their amazing offense, which had led the team to a 24-0 record over the two years since the appointment of Urban Meyer as coach, while the Spartans had, by universal agreement, the best defense in the country. The immovable Spartans stopped the unstoppable Buckeyes, 34-24.
- The 2007 Colorado Rockies came into the World Series having won ten games in a row, including sweeping their two postseason series and 21 of their last 22. They played against the Boston Red Sox...who swept them in four games.
- In 1986, the Washington Redskins, led by their vaunted offensive line, met defending Super Bowl champions the Chicago Bears, led by their explosive #1 ranked defense, in the opening round of the playoffs. The Redskins held the Bears defense to just two sacks, scored 20 unanswered points in the second half, and won the game 27-13.
- The best offense and best defense in the NFL have met in the Super Bowl exactly six times. Five of those times, the team with the best defense has won, including two soul-crushing Curb Stomp Battles in 1984note and 2013note . The one exception was in the 1989 seasonnote , and that 49ers team paired their high-octane offense with the league's third-best defense, resulting in what is still the biggest blowout in Super Bowl history.
- Given the power levels that get slung around in Exalted, it usefully has a rule for what happens when a perfect attack comes up against a perfect defense: Defense always wins.
- The World of Warcraft TCG features the Unstoppable Force (a powerful mace) and the Immovable Object (a powerful shield) as equipment cards, with a special rule that you can sacrifice a copy of the Unstoppable Force to destroy all instances of the Immovable Object in play (and vice versa). The flavor texts of both cards even read "What happens when... ?" and "Oh, that's what happens." respectively.
- In World of Warcraft there is a Mace called Unstoppable Force and a shield called Immovable Object; both were among the easiest to obtain Epic gear and really good... until the release of the first expansion pack made them next to useless.
- There exist several anecdotes of players asking Game Masters what happens if the two meet, with supposed answers ranging from "Chuck Norris dies" to "The answer is 42."
- This also inspired the Joke Weapons Stoppable Force and Moveable Object, two pieces of Vendor Trash that were useless even when they were first released, except for the little gold they brought.
- In the Suikoden universe, the True Runes were said to be born after the Sword that could cut through anything and the Shield that could stop any strike clashed.
- Perfect World: A very early quest for human characters involves meeting the salespeople in Etherblade. Playing off the Chinese (spear/armor) version of this paradox, the blacksmith claims that his spears cannot be stopped by any armor, and the tailor claims that her armor cannot be pierced by any spear.
- League of Legends: Xin Zhao has a taunt: "Find me an immovable object, and I'll put this question to rest!"
- Malphite's Unstoppable Force ultimate is now actually unstoppable. Before, you could knock him out of it by hitting him mid-charge with any stun or root.
- Even before his release, Riot has joked that Braum using Unbreakable to block Unstoppable Force would not crash the game, but would cause all of the other players to "gather round and place bets on the Rock-Man vs. Muscle-Man boxing match that is about to go down."
- In the newer lore, there's how Olaf gets to join Sejuani's Winter's Claw, the former is a nigh-unstoppable Berserker Viking that gets stronger the closer he is to death, the latter is a boar-riding lady that is utterly hard to take down. Olaf plowed through Sejuani's forces like wet paper and their personal clash caused sonic booms throughout the realm of Freljord, and none of them gained clear victory.
- The Legend of Zelda: Oracle Games have a miniboss who claims this of his sword and shield. You can't damage his shield, and you can only run away when he throws his sword at you. The solution, of course, is to get him to hit his shield with his sword.
- Directly referenced in Tyranny while the player's Fatebinder is high on hallucinogenic ink. Apparently, Rhogalus, Fatebinder of Lore, doesn't find the question enthralling.
Rhogalus: Absurd. In such a case, either the force is resistible or the object is moved.
- Overwatch has a scenario of this nature. If a charging Reinhardt (unstoppable force) meets a fortified Orisa (immovable object), the charging Reinhardt will be stopped, meaning the immovable object wins.
- In an unstoppable force vs unstoppable force scenario, if two Reinhardts charge into each other, both will be knocked down and stunned.
- Referenced by name in a achievement for Town of Salem if a fully-powered Juggernaut attacks a transformed Pestilence. In this scenario, the Juggernaut dies.
- In Romancing Saga 3, Snowman, the playable snowman who is immune to fire damage after the quest-line to recruit him serves as the Immovable Object to the boss fight Aunas' Clone a massively powerful fire entity serving as the Unstoppable Force. If the rest of the party is defeated and only those two remain, Snowman will perform a Heroic Sacrifice to slay the clone and save the party.
- One Punch Man: A Hero Nobody Knows has Saitama as a playable character, who's both the Unstoppable Force (able to defeat anyone with one punch) and Immovable Object (able to No-Sell anything and everything.) It's possible to get two Saitamas to fight each other, and if this happens, both Saitamas are technically able to damage each other, but both remain Immune to Flinching, and when one's life meter reaches zero, they simply realize that Bargain Day at the local supermarket is almost over and they leave the fight.
- Dc Universe Online: In the "World of Flashpoint" episode, Flashpoint!Batman reveals that the Flashpoint!Atleanteans and Flashpoint!Amazons have an unstoppable weapon and an unstopabbly shield, respectively. The goal of the "The Royal War" alert is to disable both the weapon and the shield.
- In Fate/stay night's Unlimited Blade Works route, Lancer* throws Gae Bolg at Archer, who counters by projecting Rho Aias. The scene is called "Lance of Sure Hit, Shield of No Loss." Result: Rho Aias is pierced, but it took pretty much all of Gae Bolg's power to do that, so Archer survives the remaining impact force.
- In an Alternate Universe rematch these same two had in Fate/Grand Order, Cu Chulainn as a Caster questions the logic behind this trope, suggesting that if such weapons are as good as they say (an unbreakable shield or an invincible spear), it all boils down to the actual skill of the wielder whether they will win or not.
- Phoenix Wright: Ace Attorney: Edgeworth tells a story of a weapon merchant presenting gifts to a lord; a spear which can pierce any armor, and a shield which can stop any weapon. The lord immediately pointed out the contradiction, embarrassing the merchant. This story inspired the design for the present day Prosecutor of the Year trophy; a broken shield, and a broken knife. Thematically, it's the equivalent of Ancient Rome's "memento mori", reminding prosecutors they are not unbeatable.
- In Umineko: When They Cry, During their duel in Episode 3, Virgilia attacks Beatrice with the Divine Spear, and Beatrice deflects it with the Divine Shield. Ronove helpfully notes that this only worked because the irresistable force must never meet the immovable object.
- Referenced in Real Life Comics here. The result in this case: the immovable object wins.
- Two Guys and Guy references it too, but only for The Unreveal.
- In Grrl Power, a villain shows up declaring that his "skin is impenetrable and [his] claws can cut through anything". Turns out the former isn't quite so true.
- In a more metaphorical sense in Ask Frisk and Company, Chara believes they can convince Frisk that the world is irredeemable to get them on their side, and Frisk believes they can turn it around and do the opposite. Flowey notes that both of them are "pretty stubborn," and concludes "So who knows?" In the end, it'll just depend on who comes out more DETERMINED.
- One of the many things the SCP Foundation keeps track of is SCP-225: an immovable* object, and an unstoppable object that roughly traces the Earth's orbit and occasionally collides with it or the Moon. They really do not want to find out what would happen if these two objects ever collided. They're drawing up planetary evacuation plans just in case. By their own admission, that might not be enough.
Since all tests thus far have shown that neither SCP-225-1 nor SCP-225-2 can be damaged or moved by any means known, the possibility also exists that neither object would be annihilated, halted, or altered from their course even by contact with the other. If this is true, then a collision between SCP-225-1 and SCP-225-2 has the potential to [DATA EXPUNGED].
- Death Battle:
- "Wolverine vs. Raiden" pit the former's absurd Healing Factor and adamantium skeleton against the latter's high-frequency blade. Raiden wins due to his sword's properties being able to compromise Wolverine's skeletal structure.
- The Hulk vs. Doomsday episode is described as an unstoppable force facing an immovable object, respectively. And in this case, the immovable object Doomsday won.
- "Carnage vs. Lucy": The former has a Healing Factor that allows him to reform from the most severe of injuries, the latter has invisible Combat Tentacles with the speed and power to function as an "Instant Death" Radius. Lucy outclasses Carnage in every way possible except for durability, which didn't matter when her destructive output rivaled nuclear weaponry and she could prey on one of his biggest weaknesses.
- Between Dante's demonic Healing Factor and Bayonetta's physics breaking feats of strength, this fight was labeled as such a clash in the post video. While Bayonetta was stronger than Dante, she still wasn't strong enough to actually kill him while she's comparatively much frailer than he, giving Dante the win.
- "Steven Universe vs. Star Butterfly". The former has natural toughness and Barrier Warrior abilities that can block attacks from powerful beings. The latter possesses magical power capable of destroying planets. Star as the Unstoppable Force wins since her destructive magic potential far surpasses anything Steven could defend or survive against, rendering her own weaker defense a moot point.
- This was examined by MinutePhysics in this video. Their answer? An "immoving" object really refers to an object that is will not accellerate, since the concept of moving depends on the frame of reference of the observer. And an unstoppable "force" refers to an object that is moving, but cannot be accelerated (so they are really the same thing). Although they would require infinite mass, and thus, infinite energy, if these objects truly could not be accelerated, then both objects would pass right through each other and continue moving. For an unstoppable force and an immovable object to exist, they must both be intangible.
- There are a number of abilities in Worm that are absolute and flat out break the laws of physics. For example, the Siberian is utterly invulnerable and cannot be impeded by any obstacle, while another character can freeze objects in time, rendering them completely impervious to any force. Their collision is referenced by this trope, and results in both powers being canceled out, with the frozen objects reverting to normal and the Siberian vanishing, as she is actually a projection.
- In one episode of Regular Show, this is what happens when Rigby learns the Death Punch in attempt to beat Mordecai at Punchies. Only for Mordecai to learn the Death Block and challenge him. The result is a stalemate... but the shockwaves produced from the ensuing attacking and blocking creates a deeper and deeper hole, to where they nearly end up in lava.
- In one Robot Chicken sketch, Zeus is giving Perseus (or possibly a Perseus action figure) magic equipment, including a sword that can pierce any armor and a shield that can stop any weapon, along with advice not to get them too close together since he isn't sure which one beats the other.
- In X-Men: Evolution, the Juggernaut and the Blob are characterized as this by the Blob. Juggy manages to move the Blob but is considerably slowed.
- Batman: The Brave and the Bold episode "Emperor Joker!" has Batmite describe Batman's relationship with The Joker as such. Likely in reference to The Dark Knight quoted above.
- The Simpsons: Used on "The Homer They Fall" to describe the boxing bout between Homer (who has been discovered to have a reinforced brain case and is theoretically knockout-proof) and returning heavyweight champion Drederick Tatum. Ultimately, this trope is defied — Tatum is capable of punching so hard that Homer is on the verge of being knocked out (or even getting pummeled to death) within ten seconds of the first round starting.
- Mighty Orbots, when a techno virus drives non-sapient machines wild, Torr muscles it out with a bulldozer and quotes this with the bulldozer as the irresistible force and himself as the immovable object. The immovable object wins when he tosses it into the air to end the stalemate.
- The phrase is invoked a lot in the late stages of the NFL season when two teams with great records play against each other. A humorously ironic example of this occurred in 2014, when the Seattle Seahawks and the Denver Broncos met in Super Bowl XLVIII. Both teams were an NFL-best 13-3, with the former boasting an historically great defense as the latter boasted an historically great offense. Pundits furiously speculated which force would come out on top, and widely anticipated it to be one of the greatest NFL games to ever be played. The Seahawks answered the bell by pounding the Broncos 43-8 in a game widely panned as one of the worst (or at least most boring) Super Bowls ever.
- Political pundits invoked this phrase more than once during the 2016 presidential election. The election was marked by a deep dissatisfaction with the establishment, resulting in the Republican nomination of businessman Donald Trump and a much better than expected showing from socialist Bernie Sanders in the Democratic primaries. This being said, Hillary Clinton was widely favored to win the general election on November 8, effectively preserving the status quo of the Obama years. Almost fittingly, the final election result reflected both of these political zeitgeists simultaneously...Hillary Clinton won the national popular vote while Donald Trump won the electoral college and the presidency.
- Scientifically speaking, an unstoppable force and an immovable object are basically the same thing - objects that no outside force can have an effect on, at least in terms of changing their movement. So if two such objects were to intersect with each other, they would both be unable to affect the other's momentum, or lack thereof, and would pass through each other. See here for a slightly more in-depth explanation of the hypothetical physics involved. Or this three and a half minutes long video by MinutePhysics.