Spanner in the Works



""A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.""

- Douglas Adams, Mostly Harmless

Whether it's The Ditz, The Fool, Inspector Oblivious, or a monkey, this miscreant is capable of derailing the most ironclad Plan by unknowningly Taking a Third Option or the most intricate Batman Gambit and implausible of Gambit Roulettes by exploiting their one, intrinsic flaw: their reliance on Contrived Coincidences, rigid patterns, and the assumption that nobody would be stupid enough to actually push the Big Red Button or fight the apparently unstoppable robot.

How can they outdo the master at his own game with nothing but stupidity and clumsiness? It's precisely because these characters are the fools and tools of fate that they are uniquely placed to derail these schemes with the gentleness of a butterfly flapping its wings...of doom!

Put another way, they are an author's walking deconstruction or Lampshade Hanging of the Theory of Narrative Causality: just as easily as a plot can come together it can be pulled apart with the tiniest, most ridiculous things.

When the character ruins the protagonists' plans by unknowingly doing something small but crucial, he becomes an Unwitting Instigator of Doom. When the Spanner can trigger a series of coincidences, it's Disaster Dominoes. When the plan is screwed and the character is also aware that he will screw the plan, and doesn't care, he becomes a Leeroy Jenkins. Occasionally, may be Mistaken for Badass. If the focus isn't on them, they're often an Unknown Character.

Compare Nice Job Fixing It, Villain, Outside Context Villain, Remembered Too Late.

Opposite of the Unwitting Pawn, often is the Unwitting Pawn until the final crucial moment. This is the main cause of Didn't See That Coming, this trope being the "that". Inverse of Unintentional Backup Plan, where a character accidentally completes an imperfect plan that would have otherwise failed. Compare with Out-Gambitted, where someone's plan is successful but ineffective against a better-thought-out plan. Compare Too Dumb to Fool, where the character is too stupid even to be baffled by explanations. Also, compare Evil Cannot Comprehend Good, where the flaw is that the villain can't see someone being generous or brave or honest enough to foul up his plan.

Specialty of The Fool. See also Didn't See That Coming, The Dog Bites Back, Who's Laughing Now?

The trope is reputedly named for the Industrial Revolution-era practice of disgruntled workers throwing a spanner into a machine, either because of fears machines would put them out of work, or as a bargaining chip for better working conditions (and often because they were the only ones who knew how to repair the machines as well).

For a literal spanner in the works, see Destruction Equals Off Switch.

(Note for Americans reading this: "Spanner" is the Queen's English word for what you Yanks call a "wrench." "Throwing a monkey wrench into it" would be the synonymous American phrase.)

Anime and Manga
"Pilaf: I wish to rule- Oolong: The panties off a hot babe!"
 * Daimos: Olban's plan for world domination started to unravel when Maradon, a gardener, found out he.
 * Death Note has a few:
 * Teru Mikami screwed up by going for his notebook when Kiyomi Takada was kidnapped by Mello, which lead Near to the notebook ... If it hadn't been for this one mistake, which allowed Near to successfully replace the notebook with a fake, Light would have won. Unusually for a Spanner, this wasn't a result of stupidity but of Mikami thinking too much like Light: he did exactly what Light would've done in his situation, with the limited information available. In the manga, Light even acknowledges this.
 * Being fair to Mikami, this could be attributed to Light's blindness as well. Since he killed Takada himself, he never even considered that Mikami might have acted on his own. If he had, he probably would have come up with some plan to counter this outcome.
 * Although, it is very unlikely that Mikami would not have at least tested the notebook before using it to culminate Light's final plan. And, in fact, in the manga it is heavily implied that Near constrained Mikami's actions in this regard by using the Death Note himself to control him, explaining why Mikami dies mysteriously 10 days later in jail.
 * Misa Amane is a borderline example: she gummed up the works all the time, but without Misa, there'd be no Rem, and then who knows how long Light would be desperately scrambling for a way to push L out of the way to his New World.
 * Misa is also a spanner for L, since up until the point that Rem and her were introduced, there was no way for Light to kill L, since he couldn't find out L's real name without the shinigami eyes.
 * Shidou, a fairly stupid shinigami, is partly responsible for Mello's escape from the police raid, because he sat still and did exactly what he'd been told to do, rather than taking his Death Note back the minute its current owner died, which would have meant that Mello couldn't have his "give me the notebook" scene.
 * That wasn't the worst thing he did. The worst thing he did was wrecking Light and Misa's alibi by revealing the fake Death Note rules. Had that not happened, even if Near suspected Light he would have no base for his suspicion, and Light would not have handed over Misa's Death Note to Mikami. And in true Didn't See That Coming fashion, Light didn't even learn about Shidou's existence until the damage was already done. Any other instance on this page either would not have happened or could not have damaged Light's plans if Shidou hadn't done that.
 * It wasn't as though that would have saved Light. After all L was already going to test and see if the fake rules were legit and Near would've done the same. The only thing that occurred because of him is that they didn't have to perform the test.
 * While we're at it, we can't forget the damage to Light's plans done by his own dad, whose attempt to bring Mello in the old fashioned way rather than kill him right then and there led to Mello's survival of the police raid, which eventually led to the incident with Mikami described above.
 * Mello certainly counts as a non-stupid example. The purpose of adding him to the show was to add someone straightforward and somewhat reckless to wreck the other main characters' quiet, roundabout and complicated plans. There is a simple, unexpected genius in just driving up in a motorcycle, tossing smoke grenades into the crowd and grabbing your target instead of laying an elaborate trap, now isn't there?
 * Mello was sort of a reverse Spanner, or perhaps a spanner used properly instead of being thrown into the works, in that his actions did not screw up Light's plans directly but rather led Near to perfect his plans.
 * Without Mello being the spanner in someone's works, Near and Light would have continued planning and counter-planning with no end in sight. That's why Near said that him and Mello together were better than L; Near could make the plans and Mello could prevent any countering of those plans.
 * Better is a bit of opinion felt on Near's part. L already gave them the structure to finish the case. After all they didn't have to start from scratch like he did. Plus, L nearly had the case solved on his own. It took a manipulated shinigami to take him down. In fact, it wouldn't have taken Near and Mello to solve the case if someone had the guts to A: Check and see if the fake rules were legit, and B: Keep an eye on Light and Misa. The only edge this troper felt they had, was the fact they were 2 people rather than 1.
 * Mugen from Samurai Champloo is a prime example. In the first episode, Mugen dispatches a horde of mooks and then approaches their boss, who then explains to Mugen how he is the son of the town's corrupt governor. Any attempts to harm the son of an important official will be a death sentence. He then confidently asks Mugen if he got all that. Mugen responds with, "Not a word," and then attacks him.
 * Mugen also manages to thwart a hostage situation simply because he was only interested in getting his kicks fighting and couldn't care less about the hostages.
 * Similarly, Mihoshi from Tenchi Muyo! actually has a distinguished service record with the Galaxy Police, but the backstory indicates it's largely a result of her bumbling in and causing too much chaos for any dastardly plan to hold up.
 * In the original OVA it was suggested she actually had had a mental breakdown from being overworked which turned her from a top cop into a comic ditz — as hinted by Kagato's comment about her past exploits. Later versions, though, lack this detail and instead are all just lucky enough to be teamed up with Kiyone, who usually can get the job done in spite of Mihoshi. Yet as evidenced by her enormous reports, Mihoshi still seems ridiculously thorough.
 * Please note that in OVA continuity Kiyone is a completely different character — that is, Tenchi's mom. And her nervous breakdown (if we are really to trust Kagato) was retconned into her impossible luck being Kuramitsus' family trait.
 * Mazinger Z, Great Mazinger, and Mazinkaiser would be so much more different had Boss not interfered with the baddies plans. To clarify:
 * In Mazinger Z, thanks to Brocken Ball, Koji is able to rescue the kidnapped civilians. Not to mention the fact that in the same series, he saved Koji's life several times, gaining Koji's respect in the process. And in the Mazinger-Z versus Great General of Darkness, as a squad of Mykene Warrior Monsters are trashing Mazinger-Z he suddenly interfered. He only deterred them for several seconds, but those seconds were all that
 * In Great Mazinger, if he would have not flirted with Jun and followed her when she was buying clothes, the good guys would be dead by the THIRD chapter.
 * In the Mazinkaiser movie, he pretty much saved the world (which at that point is a Crapsack World). The Mycene's plan to send one of their general to attack Koji while he is out of Mazinkaiser is completely foiled because Boss attacked the general with Boss Borot.
 * In Neon Genesis Evangelion, everything is going perfectly for Gendo, until Rei FINALLY decides to grow a slight sliver of self-awareness and realises that no matter how fucked up Shinji is, he would be a better choice for godhood than a) the lunatic standing with his hand in her chest (literally) b) the group of lunatics who are killing everyone Rei has ever known. So the world is destroyed, recreated and in the end everyone who want to live is allowed to live. Or SOMETHING...
 * In Super Dimension Fortress Macross, the Zentradi plans to capture the SDF-1 Macross would have succeeded without a hitch were it not for the unpredictable fighting methods of the defenders, as well as the singer Lynn Minmay.
 * In Higurashi no Naku Koro ni, . This doesn't really make things better for the main characters, though. After all, most of them are still dead. It does, however, clue a mysterious third party in on what's going on; the one aware of the Groundhog Day Loop.
 * The titular Irresponsible Captain Tylor is either the dictionary definition of this trope or the most brilliant and subtle Chessmaster in the entire show, depending on how you look at it.
 * The cat in Code Geass nearly succeeds at exposing Lelouch and wrecking all his plans simply by accidentally getting its head stuck in his Zero mask and wandering off with it. Before long, the entire boarding school has caught wind that Lelouch is chasing a cat across campus and the situation balloons into a race against time as Milly Ashford, the mischievous president of the student council, offers a bounty to anyone who can catch the cat and obtain the "embarrassing secret" she assumes it's carrying.
 * Ironically, Lelouch could count as his own Spanner: on multiple occasions, his attachment to his friends (especially Suzaku or Shirley, but especially his sister Nunnally) have caused him to make moves that jeopardize his plans or even the entire rebellion he leads. The first occurrence in R1 is where he . When was that? Second episode. The big ones are where he , and where he abandoned his followers for his kidnapped sister shortly afterward, his trait continued on in R2. This came to the logical conclusion
 * Though, to be fair,
 * Suzaku Kururugi is both this and an Unwitting Pawn. When
 * Not only that, but he messes up Schneizel's plans, as well.  Making Schneizel's attempt to blame it on Lelouch or the Black Knights completely impossible.
 * Villetta is really one of the biggest ones for Lelouch, as she figures out his identity as Zero early on (not to mention her part in Shirley's emotional descent, becomes part of the Britannian security detail spying over Lelouch due to her knowledge of and arguably immunity to Geass, and is later a key part of the betrayal in R2 19, as she is the convincing factor for Ohgi, and subsequently the rest of the Black Knights, even with a cursory amount of evidence of Geass (with respect to the truth). The latter of which ends up pushing Lelouch towards the Zero Requiem.
 * And why does she become such a problem?  Bad decision, there.
 * One of the biggest would have to be Euphemia. When Brittanian occupiers were murdering Japanese civilians by the dozens, it was easy for Lelouch's violent revolution to gain followers. But then good natured Euphemia is put in a position of power; she starts treating the Japanese people with respect, tries to find a compromise solution that both Brittania and Japan can live with, and just like that all of Lelouch's popular support goes bye-bye. Lelouch actually admits defeat to Euphemia, calling her his most formidable opponent.
 * Mireille Bouquet of Noir may be the least deadly of the assassin girls in the series (which only means that she has to obey the laws of physics), but her ability to tell the Ancient Conspiracy that it can go screw itself and her surprising faith in her partner brings down a major portion of it.
 * from My-HiME threw a big wrench in the Big Bad's plans to take over/destroy the world through the "winner" of the battle royale by enlisting the help of the most unlikely of characters:.
 * The Movie of Yes! Precure 5 has the Big Bad steal the fully-charged wish-granting device from the heroines (considering that its completion was the entire plot hook of the story, it's best not to think about why the heroes didn't use it the second they got the last MacGuffin needed to power it) and use it to try and take over the world. Nothing can stop him now... except . Oops! The scary part is that the villain, by all accounts, would have won if Ms. Cure Spanner hadn't messed everything up.
 * Cline's zeal to get rid of those he deems useless to the cause of Labyrinth in Fresh Pretty Cure only failed once, and that's because the Akarun transformed Setsuna into one of the Cures.
 * In Chrono Crusade Aion admits "No one could predict the actions of such a foolhardy young woman!" Of course, in the anime adaptation the main characters are closer to being Unwitting Pawns...
 * Monster.
 * Heroic Gambit Example: Between them, Heiji Hattori and Ai Haibara screw up a plan Detective Conan had worked out to get information on the Men in Black. Haibara, despite being an otherwise intelligent and calculating person, felt enough of an obligation to Conan that it made her insistent on going to Conan. She showed up just as the plan was going his way, and when her presence opened the door for everything to get shot to hell. Heiji's role in the Spannering was in deliberately leaving Haibara the means to locate Conan in the first place in case she chose to do exactly what she did.
 * Another, more indirect, example has an assassination attempt by the Men in Black foiled because of a little boy who kept "Ding-Dong-Ditching" one of the operatives' homes. This act ultimately put Conan in a position to foil the plot.
 * Hot-Blooded Badass Normal Sanosuke Sagara from Rurouni Kenshin once threw a wrench in Magnificent Bastard Shishio's plans by
 * Rune Soldier Louie: The idiotic sorcerer Louie ruins the Secret Weapon when he takes a leak in an unusual spot. After that he punches his way through a impenetrable barrier ruining Plan B as well.
 * In Basilisk, perfect plan to become the last man standing is ruined when.
 * This after has already put a serious kink in his plans by.
 * Ashita no Nadja has a huge Spanner situation.
 * Also, thought that hiring  as  would give him an advantage. WRONG!  Suck on that, Smug Snake.
 * Naruto example: Big Bad Uchiha Madara outright calls Naruto one of these after he defeated Pain and convinced him and Konan to turn against Akatsuki. Thus depriving Madara of Pain's resurrection technique, Amegakure's support, and the technique needed to seal the remaining two tailed beasts Gedo Mazo. Killer Bee also threw a Spanner in Akatsuki's plans when he kicked Sasuke's ass and faked his own capture to go on vacation.
 * And he does it again ... Kisame was ordered to capture him. Not only does he fail to capture him but Samehada betrays him and then the Raikage and Co. appear. Raikage and Killerbee team up and behead Kisame before he can even react.
 * Except then later it turns out he was more of a Unwitting Pawn...
 * Sasuke is one of these to Itachi's plans, which are ironically central to Sasuke. His actions prevent Itachi's plans of keeping him safe from going through... and not only that, but  Nice job, Sasuke and Itachi.
 * Madara himself is one of these to Itachi's plans as well as he started revealing Itachi's secrets to people almost immediately after he died. Itachi suspected he might do this too but unfortunately wasn't able to do anything about it.
 * Itachi, period. He's foiled or complicated the plans of every single person or organization he's come across in the series. In chronological order: And none of that counts all the ways in which he foiled his own plans multiple times over.
 * Three of the 12 Sisters in Coyote Ragtime Show, Oct, Nove, and Diesse, accidentally sent an enemy ship flying into a bomb capable of an Earthshattering Kaboom...
 * Katekyo Hitman Reborn has a mid-level mechanic incidentally named Spanner that performs a Heel Face Turn along with in an effort to take down the Future Arc's Big Bad Byakuran using his technical knowledge of the base and Millefiore. It would have slightly more effective if Byakuran wasn't an ultimate Chessmaster and the in-series King of Xanatos Speed Chess forcing the epic battles, struggles and hardships just for his own amusement.
 * Luffy from One Piece honestly doesn't care about the World Government's rule, or for that matter any of the Big Bads he faces. He just won't let anyone he cares about get hurt and will go to any lengths to protect his True Companions. Hence his defeat of two out of Seven Warlords of the Sea, the destruction of Enies Lobby, and the assault upon the most powerful jerkasses in the world. And now The surrounding politics and larger conflict don't enter his mind at all.
 * It looks like Luffy's tendency to create trouble will be Deconstructed Trope in the current arc as he's been prophesied to bring about the downfall of Fishman Island.
 * In the Assault of Marineford Arc, caused the Marines strategy for fighting Whitebeard to backfire when his body blocked a piece of a huge siege wall they were trying to activate from rising.
 * Buggy also qualifies in that same arc. His desire to grandstand and show off to a world audience led him to capture a video den-den mushi, meaning that the World Government didn't have total control over what information was getting out of Marineford when they started slaughtering the pirates mercilessly with the Pacifistas, or when Blackbeard betrayed the World Government, indelibly humiliating them in the process.
 * Dennou Coil protagonist Yasako is revealed to be this in the final episode..
 * Akiyama sees Nao Kanzaki as this in regards to the Liar Game. The Liar Game's producers break even by collecting on the players' debts, and profits when the winning contestants forfeit half of their winnings to Opt Out of the game. Nao, however, has consistently been using her winnings to pay off other players' debts while increasing her own as a result. Akiyama believes that Nao has the potential to completely bankrupt the Liar Game by doing this since by the end, her personal debt will have gotten so high actually collecting would be impossible.
 * Although the events of Cardcaptor Sakura, Tsubasa Reservoir Chronicle, and ×××HOLiC are among the most complex and densely gambited known to man, none of the respective chessmasters could anticipate the Yaoi Guys of the former two. The gambit ruling the latter one did anticipate the Yaoi Guys- but failed to anticipate a heterosexual crush.
 * Senoo Kaori in Saki does this to Mako in the same way as the poker and billiards examples listed in Real Life. Mako's playstyle is based entirely on having watched experienced players all her life. Kaori is a complete beginner. The result is that because Kaori has no idea what she's actually doing, Mako found it impossible to read her discards and ended up losing to her.
 * The military high command in Strike Witches were running a conspiracy to . Their plan was all in place and ready to go until Yoshika . Since the high command's, Yoshika's actions forced them to act prematurely and made the other Witches realize they were hiding something.
 * Full Metal Panic!: Though not a ditz or stupid like some of the other examples, kidnapping Ordinary High School Student Kaname means that you've instantly lost, because she tends to figure out ways to screw up your best laid plans. Not to mention the whole "bodyguard with Humongous Mecha" thing she has going, and how said bodyguard is the most hardcore Badass Normal the world has ever seen and such.
 * In Fullmetal Alchemist, it turns out  was the first to figure out Father's Ancient Conspiracy and think up a countermeasure before the series even starts that allows the heroes to fight back.
 * You can't help but pity Father. Despite being an Eldritch Abomination who spent centuries erecting a massive plan to gain godhood, fate sent an entire legion of fools to ruin his day. In addition to, you've got
 * In Dragon Ball, the Red Ribbon Army is a worldwide military organisation planning to use the Dragon Balls to Take Over the World. Too bad they didn't expect to be dealing with a 12-year-old boy with a stick after the Four Star Dragon Ball left to him by his deceased grandfather.
 * An earlier example would be at the end of the first Dragon Ball hunt. Pilaf has summoned the Dragon and is about to wish for world domination, but he never expects one of the good guys to escape from their prison and change the wish...like Oolong did.


 * And afterwards, preparing to kill the heroes for their interference, Pilaf's palace is destroyed by Goku, having turned into a giant monkey monster.
 * Mahou Sensei Negima has  derailing , because
 * And a biggest one has just been revealed a little ago:
 * In Durarara!!, one of the main reasons Izaya hates Shizuo so much is because his emotional volatility, Too Dumb to Fool nature, and firmly sustained belief that Izaya is responsible for 99.9% of everything that goes wrong in Ikebururo makes him liable to become the Spanner in the Works at any moment..
 * In Baccano!'s Flying Pussyfoot arc, it seems like everyone is this for everyone else, in a plot that was already capable of being summed up in one word: "clusterfuck." All of these plans disrupt one another in spectacular fashion and end in varying levels of success based - with one or two notable exceptions - on how sympathetic the characters involved are.
 * In Pokémon Special, Giovanni has a Game Breaker Deoxys that can Forme Change instantaneously at will. Yes, he's pretty much unstoppable...until Bill and his buddies figure out how it works and disable it.
 * During the finale of Pokémon: Zoroark: Master of Illusions,
 * In A Certain Magical Index, Touma often derails the complex plans of any character by simply showing up and kicking the crap out of every bad guy in sight. Subverted in that Laura Stewart and Aleister Crowley are Magnificent Bastards and can factor him into their schemes. Later, Aleister has a Villainous Breakdown when, raging that it's impossible and ordering his death in an effort to stop him from derailing his calculations any further.
 * In the Makai Arc of Yu Yu Hakusho, Yusuke's decision to hold a tournament was a last ditch effort to eliminate Yomi and Mukuro, since Yusuke knew he had no hope of taking either of them in a fight. However, due to Kurama and co.'s lucky presence, and Mukuro's bugging of Yomi's estate, Yusuke's idea prevents all hell from breaking loose: if Yomi were to simply attempt to kill Yusuke, Kurama, as well as his own elite fighters, would side with Yusuke. While Yomi would be capable of killing them all, he'd expend at least a third of his power doing so, leaving him vulnerable to Mukuro and Hiei, all of this forcing Yomi to accept Yusuke's proposal.
 * In Beast King Golion, Honerva's plan to take down Altea by  falls victim to two spanners- one was Kurogane in Red Lion coming up with the idea , and when Galra attacks again before Altea could train a replacement,.
 * Tiger and Bunny has
 * There is also.
 * pretty much tells  that he became one for her   in episode 11 of Mawaru Penguindrum. This, because
 * The entirety of the Principality of Zeon is just one big spanner against themselves in Mobile Suit Gundam's One Year War. Among them being:
 * M'Quve refusing to give Ramba Ral the new Doms, leading to his death and later that of the Black Tri-Stars.
 * Sayla and Amuro spotting a Federation traitor just before Operation Odessa.
 * Ghinias Sahaku snapping and attacking, leading to the death of his own men that his sister Aina had brokered for a cease-fire to get them out for medical attention.
 * Zeon soldiers thinking the Gundam had been destroyed early on in the Battle of Solomon, leading Anaval Gato to break away and miss fighting Amuro.
 * Zeon's over-reliance on Mobile Armors
 * Ghiren firing a superweapon too early just to kill his own father.
 * Kycillia killing Ghiren, leading to the Delaz Fleet to bail. And to think, they had spent nine months at that point in a stalemate and were really close to winning.

Comic Books
"Snively: Eccentrics aside, he really is a genius. He can build the most amazing things and plot a hundred steps ahead ... And then there's you. All the building, calculating, and planning in the world couldn't beat you."
 * In IDW's Transformers series, Shockwave, planning to seed dozens of worlds with super energon so Cybertorn wouldn't be mined hollow and die, is attacked by the Dynobots looking for revenge.
 * In the Mad Thinker's original appearance in Fantastic Four, he manages to overcome all the defenses of the Baxter Building, take control of it, and trap the heroes. His plan fails to account for their mailman, who cuts the power.
 * Wrong example, as the mailman is asked by Reed Richards to do it at an exact time to foil Mad Thinker's plan. So it's just Reed Richard's badassery at work.
 * This is actually the Mad Thinker's hat, in a way - He's able to create amazingly complex, unassailable plans at the drop of a hat, however there is always some random variable (what he calls the "x-factor") that doesn't take into account and buggers up his calculations.
 * Marvel Adventures Spider-Man once established that the Thinker hates Spider-Man because his precognitive spider sense makes him the one person on Earth who can effortlessly derail the Thinker's schemes without even deliberately trying.
 * Zayne Carrick in Knights of the Old Republic basically sets in motion the Self-Fulfilling Prophecy of the Jedi—the one that they were trying to escape by killing their Padawans—when he (unintentionally) misses the knighting ceremony and then escapes. He continues to thwart their plans, intentionally or not, ever since.
 * He also thwarts Arkoh Adasca's plan (with the help of Lucien and Alek) by tricking the Mandalorian leader into thinking Adasca is working with the Republic to trap him, which results in a three way brawl which culminates in Adasca's ship getting eat by giant space slugs.
 * Runaways often sees villains' perfect plans ripped to shreds by Badass Normal Chase Stein, who claims to be street smart but as a fellow teammate inquired, "What street? Sesame Street?" It should be noted that he isn't inept, as he did find the first base and the unassuming white van he drives was requested by him for his first car (over fast sports cars that his parents could afford) because he had paid attention to the DC beltway sniper incident (which went on as long as it did because cops were looking for a car that wasn't involved, when the killer was driving an extremely common kind of van).
 * Best seen near the end of volume 1. dumbfounded reaction to  is priceless.
 * In DC Comics, the Challengers of the Unknown are a team of adventure-seekers who miraculously survived a terrible plane crash, and therefore decided that they would willingly face any danger because, as they always put it, they were living on "borrowed time." It has recently been revealed that this is literally true: because they did not die on their appointed death date, the Challengers are the only people in the world whose fates are not recorded in the Book of Destiny. They can freely disrupt predestined events that would otherwise be literally inevitable, making them the ultimate example of this trope.
 * Subverted in the Dan Dare series Reign of the Robots, wherein the only person that the Mekon paralyses after capturing the group is Dare's bumbling aide Digby, on the grounds that "he has no brain, therefore there is no predicting his actions".
 * Groo the Wanderer is this trope incarnate. One of his more memorable derailings involved him going up against a mind-reading sorcerer. Groo fights his way to the sorcerer's throneroom, is confronted confidently by him... followed by a full page of the sorcerer making strange faces at Groo while the latter stared at him in befuddlement until he finally screamed "There's no mind to read!" and ran away.
 * In Cerebus, the title character is also this trope incarnate, as he possesses a "magnifier" quality that influences everything and everyone around him to varying degrees. This causes the plans of everyone who tries to do anything that directly involves Cerebus to succeed wildly then crash spectacularly.
 * Deadpool is frequently seen as such a rogue element that the guy who can copy someone's fighting style completely (Taskmaster) was still surprised by him.
 * There's another event (context is unknown) in which a genius tactician of some kind The Savage Land mutate Brainchild is countering the moves of every other hero in their attack on his base, but none of his predictions of where Deadpool is are accurate; turns out DP took the "Super Mario Bros strategy" and went through the sewer pipes.
 * I don't remember the context either, but it had an army of dinosaurs in it.
 * Cable/Deadpool #50. The final issue of the series.
 * Cyclops in the Ultimate X-Men arc Return of the King. Let us recap the situation so far. Magneto has regained his memories and is going on a rampage across the world with his acolytes while he waits for Forge to get his Doomsday Weapon ready. All the X-Men are either captured, killed, or on the run and still have no idea where Magneto's base is. It looks like all hope is lost, when Cyclops, who everyone thought was killed by Wolverine a few issues ago, is taken into Magneto's base as an injured mutant in need of healing. After recovering Cyke busts his way out, clues the other X-Men in on where the base is. All of this leads to a truly epic smackdown against Magneto and saving the world.
 * In one week-long FoxTrot series, Jason finds it impossible to beat one guardian monster in a video game, as it instantly squashes his character every time he tries. Paige, who almost never plays video games, takes the controller and gets by the guardian by simply walking around him.
 * Snively describes Sonic as this in the Archie Comic's 200th issue after the blue blur defeats Eggman yet again,.


 * Snively's not the only one who's noticed this.
 * Cebolinha/Jimmy Five from Brazilian comic Monica's Gang is known for "infallible plans" against Monica. They usually work up until a certain point, when "accomplice" Cascão/Smudge screws up, usually by revealing it was a plan.
 * In Tintin and the Picaros, Colonel Sponsz plots to have his old enemies (i.e. Tintin, Haddock and Calculus) be the subjects of a fake kidnapping by Tapioca's nemesis (and Tintin's old friend) Alcazar so they can all fall victim to an ambush on a back road. The Spanner in the Works is a monkey in the road, which causes Alcazar's getaway truck to suddenly swerve the moment it comes into firing range.
 * In the Fables spinoff The Nearly Great Escape, Jack figures out that Goldilocks is working for Revise because she wears the same style of glasses that several of his minions wear. This is a complete coincidence, but it turns out that he was right anyway.
 * An early Spider-Man issue has Mysterio convincing Spider-Man that he's going insane, and then posing as a therapist who offers to help our web-headed hero. Of course, Mysterio then sets up more illusions to make Spidey think he's hallucinating again. Spidey's about to have a complete nervous breakdown when J. Jonah Jameson and Flash Thompson, who had both heard about the therapy session and wanted to support Mysterio and Spider-Man (respectively) wander into the house. When they start seeing and reacting to the same "hallucinations", Spider-Man realizes that he's being conned, and swiftly defeats Mysterio. It's later lampshaded when Jameson realizes that Mysterio was on the verge of making Spider-Man reveal his Secret Identity, and that his own arrival torpedoed the whole plan. After that, Jameson is the one who seems like he needs therapy.
 * In Justice, Lex Luthor and the other bad guys come up with an extremely brilliant plan to destroy the heroes. It almost works, but they ignored a few guys like Captain Marvel, The Phantom Stranger, and The Metal Men. To be fair, how could they counter The Phantom Stranger?
 * Batman, or rather Bruce Wayne, was this to the Court of Owls.
 * Margaret from Yoko Tsuno's story The pray and the shadow.
 * Margaret from Yoko Tsuno's story The pray and the shadow.

Fan Works
""But mostly? The assorted plans at play here would be going very, very wrong due to the actions of a no-name, no-count, utterly talentless Magus by the name of Shirou Emiya. He had no magic worth mentioning, no combat experience of note, and no plan for or knowledge of the War he was about to enter. He did, however, have one trait that had derailed a countless number of such grand, far-reaching schemes throughout history. You see, he really, really wanted to be a hero.""
 * The Fate/stay night fanfic Chaos Theory opens up with this. It introduces the plots and manipulations of all the antagonists of FSN, and then the narrator calmly declares:


 * In Ultimate Sleepwalker: The New Dreams, the Green Goblin kidnapped and planned to publicly murder Gwen Stacy as a way to get revenge on her father, Captain George Stacy of the NYPD. While Spider-Man intervened and tried to rescue Gwen, the Goblin had anticipated that and set things up so he'd be able to kill both Spider-Man and Gwen at the same time. Unfortunately, what he didn't take into account was Sleepwalker following Spider-Man to the top of the bridge and distracting him long enough for Spider-Man to rescue Gwen and get her to safety. The Goblin proceeded to have a Villainous Breakdown.
 * The Pony POV Series has one that's notable for the exceptionally long time required for the spanner to actually get into the villain's works.
 * In the Neon Genesis Evangelion fanfic RE-TAKE, SEELE finds all their plans foiled by something they could never have anticipated

Film
"Pike: Here's what I think of your best laid plans! Pike fires the SMAW into the ship's hull"
 * Arguably Thor in The Avengers. Had he not been there to keep the Hulk at bay the Helicarrier would have crashed and Loki's plan would have more than likely been successful.
 * The ending of the film Layer Cake has the protagonist outclassed not by dumb luck, but by Because while he was really successful in tricking clever criminals in his Batman Gambit, he
 * Carlito's Way ends in a similar fashion. After outsmarting all his enemies by the skin of his teeth
 * Star Wars has a few examples:
 * The Ewoks in Return of the Jedi are the one tiny overlooked factor that brings the Emperor's entire grand scheme crashing down.
 * Luke just happens to wound Vader in the same way Vader wounded him, thus making Luke realize what he had almost become. Of course, the Emperor really wasn't helping his own cause, either.
 * The Expanded Universe has the entire Imperial Fleet artificially boosted by the Emperor's force powers. The Emperor's death ended up causing the imperial officers to lose control of the situation, preventing them from shooting down the Millennium Falcon before it could destroy the Death Star 2.
 * There's also Jar Jar Binks, whose clumsiness is more than a match for several tanks.
 * There are about a dozen ways the Rebels lucked into the plans for the Death Star in the expanded universe. By now you'd think they had enough plans to spare.
 * Anakin Skywalker's destroying the Trade Federation's droid control station in the first prequel was a massive stroke of luck. To the extent that not even he realized what was happening. He just hid in an unmanned Naboo fighter and stuff happened.
 * The scheming husband in Dial M for Murder is undone because he underestimates the intelligence of Swann/Lesgate, the thug he hired to kill his wife. Swann puts the key right back after using it, rather than keeping it, as his employer expected.
 * In the recent adaptation of The Pink Panther, it seems like Inspector Clouseau, a seemingly Inspector Oblivious is one of these until the very end, where he reveals that he was a Chessmaster after all. According to Peter Sellers, the original Clouseau qualified as well, but he knew he was a buffoon deep down. Strikes Again had killers from all over the world come after him. Likewise in the film's Denouement,
 * Sweeney Todd: The Demon Barber of Fleet Street: Sweeney Todd would have killed Judge Turpin and ended the movie right there and then in the middle had Anthony, who had recently talked to Sweeney about his plan to elope with Johanna in order to get her away from Turpin, not busted into his shop with the judge right there in the room in order to inform Sweeney that he has found Johanna and that she has agreed to the plan. Needless to say, this ends up blowing both the aforementioned plan and Sweeney's attempt to kill Turpin straight to hell.
 * All throughout Pirates of the Caribbean: Curse of the Black Pearl, Jack repeatedly plots for the most favorable outcome (for himself), but stubborn fool Will Turner and arrogant Jerkass Captain Barbossa assume they know best how to get things done, and nearly screw themselves out of their goals frequently. If Barbossa had wanted to cut Elizabeth's throat instead of her hand, Will would've been too late to save her on his own, and if Will had died like he should've when Barbossa ordered the Interceptor scuttled with Will trapped below, Barbossa would never have gotten Will's blood to pay Bill Turner's debt. Near the end of the film before the climactic battle, Jack has everybody where he wants them, but because Barbossa and Norrington don't trust him at all, his plans almost fall apart.
 * That's what Jack wants you to think.
 * In the 1932 sci-fi mystery film Doctor X the Mad Scientist Serial Killer manages to not only but also . Unfortunately he forgot about the Plucky Comic Relief Intrepid Reporter,.
 * In The Caper film The Killing, a band of criminals pull off an elaborate robbery of a racetrack. Even though the, the Anti-Hero and his Love Interest manage to . However, all their plans are foiled when.
 * In The Man Who Knew Too Little the main character foils a terrorist plot without even knowing there was one.
 * The Joker in The Dark Knight Saga describes himself as a kind of non-stupid Spanner ('I'm a dog chasing cars: wouldn't know what to do with one if I caught it!'). Really, his Gambit is just bigger than yours. His Character Filibuster about chaos and anarchy derailing 'the plan' could be either hanging a lampshade on this trope, and subverting the hell out of it. Or both. You decide.
 * And the people in Gotham turn out to be the ones who ruin his plan.
 * In Batman Begins, Batman himself is the Spanner towards and the Scarecrow's plan to destroy Gotham.
 * Oh, the joys of Chicken Run - this is one of many visual gags, and surprisingly one that is relevant to the plot.
 * In Cast a Deadly Spell,
 * Clue: Mr. Boddy tries to get one of his six blackmail victims to kill his butler Wadsworth to prevent him from reporting him to the police; instead, one of them kills Boddy. One of the film's three endings however, revealed an even bigger Batman Gambit: This one is ruined by
 * The terrorists from Vantage Point might have gotten away with it, had it not been for a little girl.
 * In The a Team, would have gone off smoothly if not for  {spoiler|Pike having a SMAW.}}


 * Die Hard: Cowboy Cop John McClane's real job. When terrorists are confidently moving chess pieces behind the scenes, he knows that all he has to do is look for something sensitive and start whaling on it.
 * The Adjustment Bureau tries to contain this kind of incidents. But they are not above random chance and unexpected behavior.
 * Gina in Unknown. Despite just being his cab driver, she saves Dr. Harris' life at the beginning of the movie and twice afterwards, which also allows Harris to stop the plan of the Big Bad.
 * In A Few Good Men, it becomes apparent the that the Department of the Navy very much wants the case of United States v. Dawson & Downey to be quietly resolved by a Plea Bargain so as to prevent incident from causing too much embarssment to the Marine Corps. This plan is undone by the dual spanners of Galloway and Dawson; Galloway, not because she is dumb, but be because she is clever enough to sense the somthing in not right and thus goads Kaffee in doing his due dilligence for once instead of rushing to a Plea Bargain, Dawson, for being too hardcore of a jarhead to willingly accept a dishonorable discharge because it would make thing easier for him, and telling Kaffee to take his plea bargain and shove it.
 * In The Atomic Brain, as shown on the TV series Mystery Science Theater 3000, in spades. The main plot for the villain Miss Marsh was for her to have her brain swapped with the prettiest girl of three chosen. That gets ruined when the homeliest of the three, who had her brain swapped with the cat's, gouges her eye out. Miss Marsh's companion tries to double-cross her, killing her and letting the remaining girl take her money, but Marsh kills him. The scientist, Dr. Otto Frank, pulls one by placing Miss Marsh's brain with the cat's, revealing that he wanted to keep her locked away in the cat so he could use her money to continue his research on reviving the dead. Miss March responds by locking him in the revival chamber and setting the dial to "Frag the entire house".

Literature

 * A ditzy cultist hands the newborn Antichrist off to the wrong unsuspecting parents in the beginning of Good Omens, thus setting off a plan that
 * Of course, this may have all been a bigger
 * Used and inverted in J. R. R. Tolkien's The Lord of the Rings. In order to destroy the One Ring and defeat Sauron once and for all, Gandalf develops an Indy Ploy / Batman Gambit to sneak the ring right under Sauron's nose eye into Mordor and Mount Doom, the one place it can actually be destroyed. It almost worked except the One Ring itself spans the plan by finally corrupting Frodo. Then Gollum anti-spans the One Ring's spanning by grabbing it and accidentally falling into Mount Doom.
 * Supposedly, Gandalf knew that the Ring would ultimately corrupt Frodo, especially since it would be the most powerful within the Cracks of Doom, and that another Spanner like Gollum would have to occur for the plan to work.
 * In Isaac Asimov's Forward the Foundation amidst the chaos surrounding high-level plots and counter-plots, Galactic Emperor Cleon I.
 * Gunner First Class Ferik Jurgen, assistant to Ciaphas Cain, turns out to be the one who most often saves the day, with his combination of being a "blank" who nullifies psychic powers and the fact that he carries a really, really big gun.
 * Discworld:
 * Witches Abroad had a Batman Gambit based on Narrative Causality fall apart before the sheer onslaught of Nanny Ogg's ordinariness.
 * Rincewind never wants to get involved in events, being a coward. In Interesting Times, his great ambition is to stay as far away from the villain's Evil Plan as possible. However, he always seems to run away from danger in the direction of even more danger... until he winds up cornered and desperate, at which point he does the right thing in spite of himself.
 * Some of the more inept members of the Ankh-Morpork City Watch, especially Sergeant Colon and Corporal Nobbs, fit this trope.
 * Lu Tze is a professional, very intelligent Spanner, and legendary for being so among the History Monks. The secret to his success is that no one pays any attention to the little, wrinkly, smiling old man sweeping the floors.
 * The A Song of Ice and Fire book A Feast For Crows has Lysa. And Jaime. And Robb. And Allerie. And Roose. And so on and so forth. Westeros is so awash in spanners it's a wonder that it's ever experienced peace. But of course, as anyone who's finished Dance with Dragons knows,
 * As early as the first book, Bran and  is a huge spanner. It was a complete coincidence and no one - not even chessmasters like Littlefinger or Varys - could have predicted it, yet it directly sparked a chain of events that would eventually lead to, the main conflict of the series.
 * Joffrey can also be a spanner at times: While for the most part he's fairly predictable, his cruelty and insanity occasionally lead him to do things that no one would expect, such as . And let's not forget that even before he became king, he was the one who.
 * The Repairer of Reputations, one of the short stories in The King in Yellow, has the evil scheme being foiled by Then again, since most people involved were insane, the plan might not have worked anyway.
 * Kender, gully dwarves and gnomes in the Dragonlance series...especially (by their very nature) the kender. While all of the above races have the ability to change events in the past through time travel, due to their origins as races created by the Greygem of Gargath (pure Chaos-in-a-rock), kender have innate fearlessness, insatiable curiosity, guileless but mischievous personalities, and chronic kleptomania as racial traits. Tasselhoff Burrfoot, for example, is both the Unwitting Pawn of Raistlin's evil schemes and the only person unpredictable enough to screw them up. One of the most dreaded sounds on Krynn is the sound of a kender saying 'Oops.'
 * Given the choice between being locked in a room with a hungry dragon or a bored kender, anyone with any sense picks the dragon.
 * Remember, the cruelest thing one can do to a kender is lock him up. The cruelest thing one can do to anyone else is to lock them up with a kender.
 * This trope is sort of lampshaded in the second Honor Harrington novel where the protagonist explains to her subordinate that the best swordsman in the world doesn't fear the second-best one, but the worst swordsman in the world, because he can't predict what the dumb son of a bitch will do.
 * Apparently there is some truth in that. An inexperienced swordsman is more likely to do something that gets both combatants killed than an experienced one trying to avoid dying.
 * A similar thing happens in the Age Of Unreason series, where a guy is killed by someone who cannot fence at all; he automatically assumed his attack was a mere feint, because no fencer would make such a clumsy attack. Too bad his opponent is not a fencer...
 * The line about the world's best swordsman is actually a quote from Mark Twain's A Connecticut Yankee in King Arthur's Court.
 * A character in Echos of Honor is known as "Silver Spanner" Maxwell, after a Noodle Incident involving a dropped spanner produced spectacular (and expensive) results, six years previously.
 * Aivars Terekhov pulls this in The Shadow of Saganami when his ship happens to encounter the same ship, using two different identities on two different planets, running weapons to terrorists on two different planets. Using evidence found on that ship, Terekhov figures out the antagonists' plan and quickly rushes to put a stop to it.
 * Arnold Giancola is this on a couple of levels. His actions doctoring diplomatic correspondence led to a resumption of the war when his plan to score a political coup backfired spectacularly. Despite other characters believing he was, he actually was not . Later, his purely accidental death further derails investigation meant to examine his original actions.
 * John "Anjin-san" Blackthorne in Shogun is a rather magnificent one, as circumstances force him into a key role in the Gambit Pileup of choosing Japan's next shogun in the year 1600. And he's based on a real guy, to boot.
 * Tom Clancy's Executive Orders: A pair of domestic terrorists spend most of the book preparing a massive cement truck bomb to kill Jack Ryan, driving it all the way across the country, dodging roadblocks put up as a result of The Virus spread by the other Big Bad of the book, only to be pulled over and arrested by a random Highway Patrolman just doing his job when they panic.
 * The titular assassin of Frederick Forsyth's The Day of the Jackal seems well ahead of the international police effort to stop his attempt on Charles de Gaulle until some things come up to derail his plan. Just one of many comes up when his seduction of a baroness to gain a hiding location falls apart when said baroness eavesdrops on a call with his informant, forcing him to kill her and letting the police make him publicly wanted as a common murderer.
 * And ironically, his last spanner was de Gaulle himself, who leaned forward to kiss a recipient on the cheeks instead of shaking his hand like the Jackal expected, therefore making the Jackal's shot miss and giving Lebel enough time to stop him.
 * David Eddings's Tamuli trilogy reveals that the Child-Goddess Aphrael and her priestess Sephrenia were this to a Man Behind the Man without ever realizing it until his plans were exposed.
 * And in fact, main protagonist Sparhawk is essentially a personification of this trope. As the "man without destiny," no one can really divine or guess what exactly he's going to do in the future...not even the gods, who are scared shitless of him.
 * In James Swallow's Warhammer 40,000 Deus Sanguinius, Rafen shocks Arkio's forces by . is quite glad that he will die in single combat, because he had landed in the plans by a fluke and quickly grown to "the most serious nuisance." Of course, he wasn't dead at that point.
 * Mat Cauthon in The Wheel of Time almost literally personifies this trope. He isn't stupid, but he's rarely clued into just what exactly is going on around him. Despite this he foils many schemes, especially when he's actively trying not to.
 * And similar to the line mentioned in Honor Harrington above, when the White Tower's weapons master tells Galad, Gawyn, and Mat a story about history's greatest swordsman, who was only defeated once in his entire life - by a random farmer with a stick.
 * The War of the Worlds is essentially one long Curb Stomp Battle with the invading Martians effortlessly rolling over all of humanity's attempts to stop them. Then a month later they all die of common Earth diseases, germs and therefore antibodies being non-existent on Mars.
 * In the last The Chronicles of Narnia novel, The Last Battle, the villains come pretty close to winning. What ultimately derails their schemes?
 * In Rainbow Six,  is the first in a series of little things that clue The Dragon in to the true nature of Rainbow despite efforts to hide it. Carlos the Jackal's fellow criminals, in carrying out an attack to try and get him freed, gets the team some good publicity that gets them to view the Sydney Olympics for free and puts them in the right place to foil a vital part of the villain's plan. One of the villains' captives manages to get off an email, the investigation into which eventually helps lead the way to them. One of the named minions
 * In Stephen King's The Stand, Randall Flagg (the demonic Big Bad) recruits Trashcan Man and sends him out into post-apocalypse America to look for stuff with which to destroy the good guys. He brings back a literal the city of Las Vegas while Flagg is distracted trying to crucify tear the remaining heroes limb from limb.
 * In the Dale Brown novel Executive Intent,  would have avoided capture by GRU agents had he not stumbled over a random civilian in the wrong place at the wrong time, who proceeded to inform the police and make the already suspicious GRU agents take action.
 * John Lennon's short story "A Spaniard in the Works" has very little to do with this trope. Or, for that matter, anything else.
 * In |Bystander the villains run into a very severe example of this, when they have a great plan to capture Lucretica, and are foiled by two details. One, they have a severely incorrect estimation of her power level, and two:.
 * Fortunately, Lucretcia's complete inability to fight helps put their plans back on track..
 * In Harry Potter and the Half-Blood Prince, Draco Malfoy's act of completely derails the gambits that both Dumbledore and Voldemort had in place in regards to the . Though with a bit of luck it ends up working out great for Harry himself.
 * Fireheart in Warrior Cats. He completely ruins Tigerclaw's plans by running into the cave where Tigerclaw was during a battle and beating Tigerclaw up.
 * In The Dresden Files novel Changes, they are able to narrow down the location of where the sacrifice will occur because even though the records for the first shipment were destroyed, the red court still had to transfer another shipment due to the fact that the previous shipment was incomplete due to minion carelessness. As such they needed to keep one copy of the records intact until after the final checkup and they kept the records in the van they needed to use to transport the goods. As such Harry is able to narrow it down and eventually find Chichen Itza, enabling him to blow the Red Court's plan sky high.
 * Harry in general serves as a Spanner in the Works of many a grand villainous plan, in much the same fashion as John McClane.
 * In Queste, the fourth book of Septimus Heap, Jenna and Beetle are this to.
 * In The Dance of Time, the final book of Eric Flint's Belisarius Series, there is a side plot of a Malwa assassination team tasked to kill Byzantine Emperor Photius and Empress Tahmina but keeps getting foiled by unexpected changes of plans of their targets. The team follows them for thousands of miles while the plot of the rest of the novel occurs around them. At the end they . They get rewarded by being sent into exile with the series' Manipulative Bastard.
 * In The Demon Headmaster books, Dinah manages to be both this and an Unwitting Pawn at various points. The Headmaster can easily hypnotize her, and she's very close to being his greatest asset, but she's just intelligent enough to shake it off and bugger it all up at the last minute. For the record:
 * Book One is the one where they meet. He doesn't know her capabilities.
 * Book Two has him not knowing her new name.
 * Book Three has him not even realising she could figure it out. To be fair, she figures it out entirely by simply hitting the pause button on the tape.
 * Book Four has him specifically targeting her for her DNA.
 * Book Five has, who doesn't even know she exists. Dinah stumbles on this one purely by accident.
 * The final book has him
 * In one of Francoise Rivier and Michel Laponte's Jonathan Cap books, recurrent character and local Plucky Girl Juliette becomes this.  It turns out   The plan would've gone smoothly,

Live-Action TV
"Jack O'Neill: So what you're basically saying is you need someone dumber than you? General Hammond: I'm sorry, Thor, but we need SG-1 here. Sam Carter: I could go, sir. Jack O'Neill: I dunno, Carter, you may not be dumb enough."
 * Doctor Who:
 * In the story City of Death, Duggan, the detective who seems to have gotten into his line of work just because he likes hitting things, derails the villain's multi-millennial scheme with one thoughtless, well-timed punch.
 * In the episode The Pirate Planet, after all the planning to destroy the Mentiads by both a cyborg pirate captain and a tyrannical Queen Xanxia in disguise, the Mentiads and the Doctor manage to do this trope... literally.
 * In the story "The Caves of Androzani", unusually, the Doctor's role in the story is limited to frantically attempting to get him and Peri out alive. His mere presence, however, inadvertently causes the entire messed-up Androzani society to implode. The Doctor brings down a corrupt government accidentally.
 * Get Smart, of course; Maxwell Smart is more likely to defeat KAOS by accident than on purpose.
 * A British Sketch Comedy program parodied this. A man is buying a camera, and is shown one that is "totally idiot proof". He then smashes it on the table. "What did you do that for?" "Well, I'm an idiot." The shopkeeper then shows him a camera made out of concrete.
 * In an episode of Wallander, the title character avoids a fatal bullet by tripping over a conveniently-placed rug.
 * In TNA, Taylor Wilde and Lauren Brooke derailed Dr. Stevie's attempts to turn Abyss into his puppet. Despite using drugs, physical abuse, and mind games to keep him in line, Dr. Stevie didn't count on Abyss falling in love with Lauren. Then, when he ordered Abyss to attack Taylor, he didn't count on her being Lauren's best friend...
 * Married... with Children: Kelly Bundy tended to mess up whatever plan she became involved in, given her role as The Ditz, The Ditz and Brainless Beauty. It's even lampshaded by Peggy at one point as the Bundys and the D'Arcys are being arrested by the police, when she notes that it probably wasn't a good idea to let Kelly in on the plan.
 * Angel has this when a sorcerer's plan to sacrifice his virgin daughter for power is thwarted when it turns out
 * The Season 5 finale of Weeds features an unusual instance of a smart character acting as fate's tool:
 * Firefly has a rare example of this happening to the hero. In "Objects In Space", 's Batman Gambit to is almost dashed by  Fortunately,
 * Stargate SG-1: SG-1 was once called to help Thor to serve this very purpose.


 * In the third series of Primeval, Helen has a plan to She very nearly succeeds, if not for.
 * The main characters in The Good Guys are generally competent cops (yes, even Dan Stark) who solve major crimes largely by stumbling into them while investigating something much smaller.
 * Shotaro from Kamen Rider Double is this trope incarnated. He's always the last thing the villains take into account. He even becomes this  It happens so often,
 * In Survivor: Heroes Vs. Villains, Tyson served as a Spanner In The Works for Rob's gambit by serving as an Unwitting Pawn in Russell's gambit. The Villains tribe was divided between Rob's and Russell's supporters, with Rob leading 6-3. However, Russell had an immunity idol, which meant that when the tribe voted someone out, he (or whoever he gave the idol to) could stand up and play the idol to prevent any votes cast against them from counting. Rob wasn't sure whether the idol would be played by Russell or by Russell's closest ally, Pavarti, but Rob had a plan to guarantee they could get rid of either Russell or Pavarti. He would have three people vote for Russell and three for Pavarti; then, regardless of who played the idol, the other one would have three votes. Even if all three people on Russell's side voted for one person, it would have meant a 3-3 tie between votes to get rid of Russell or Parvati and votes to get rid of whichever Rob supporter Russell targeted, leading to a tie-breaker that Rob's side could easily win. However, the plan fell through because Tyson actually let Russell (his alliance's enemy) tell him who he should vote for. Rob had assigned Tyson to be one of the three people to vote for Russell. However, Russell told Tyson that he would sacrifice Pavarti and use the idol to protect himself, leading Tyson to think that he should vote for Pavarti because votes against Russell wouldn't count after Russell played the idol. Russell had other plans, and gave the idol to Pavarti. After the votes were cast, Pavarti played the idol, meaning that the final vote count was four votes (including Tyson's) against Pavarti that didn't count, two votes against Russell, and three votes cast by Russell and his allies against... Tyson. It was three to two, and Tyson was sent home. Afterward, Tyson admitted to the camera, "I am a victim of my own stupidity." His action was one of five official nominees for the dumbest action in Survivor history.
 * Sash fell victim to three Spanners during Nicaragua. He was in a very good position in the game, having just ousted Chessmasters Marty and Brenda in quick succession, but then his closest allies Kelly and NaOnka decided to quit at the same time, leaving him without an ideal final three (Kelly did very little in both strategy and physical play, and NaOnka was universally disliked by the other tribemates). He managed to quickly get himself into a secret alliance with Chase, Holly, and Jane, but then Fabio, who was both the alliance's obvious target and had been faking the part of the Dumb Blonde up until that point, planted the idea in Chase's head that Jane needed to be taken out before anyone else. Sash proceeded to make the plan his own, which in turn led to Jane revealing the alliance at the next Tribal. From there, Sash could only helplessly watch as Fabio went on a string of Immunity Challenge runs, keeping him safe to the very end, which forced Sash to turn on his alliance and vote out Holly. The end result? A Final three of Sash, Chase, and Fabio, with Chase getting four votes, Fabio winning with five, and Sash with... none at all.
 * An episode of Fringe features a villain whose intelligence was boosted so he can perfectly predict anything that will happen and set up ridiculously complicated scenarios to kill people and escape from the agents chasing him. He's foiled by
 * This trope has made the lives of the investigators on CSI much, much easier over the years. Whether it's people discovering a dead body before it can be completely dissolved or buried, witnesses who unwittingly provide evidence that ties a murderer to a crime scene, or a Heroic Bystander who catches a Peeping Tom that also turns out to be a serial rapist, various members of the public have helped the CSIs bring a lot of criminals to justice in many different ways.
 * Tragically, Lancelot became this for Arthur and Guinevere on Merlin despite repeated promises to himself and Merlin that he would never come between them. However, Morgana resurrects him after his Heroic Sacrifice, robs him of his free will, and forces him to seduce Guinevere (who was enchanted to respond to his advances).
 * In the first volume of Heroes, there was a large and complicated plot that involved blowing up New York in order to usher one of the characters into the White House. The only thing stopping it from being a Gambit Roulette was the fact that the people responsible were basing their convoluted plot on the works of an artist who could paint the future. And it was working, hell, it almost did work. Unfortunately for them, a certain Future Badass with the power to control the Space-Time continuum didn't like the result, and traveled back five years to give a message to one of the present day characters. This guy had no idea that there was any sort of plan, he just thought it all happened naturally, but the message he delivered set off a chain of events that ended up ruining the plan at the last minute.
 * Leverage: In "The Gold Job" Hardison demands, and is given, the opportunity to run his own con by Nate. Hardison plans an elaborate Batman Gambit based on video game theory and it's working very well, until the people he's manipulating decide that it's not worth the effort to keep jumping through his hoops. In an ending scene Hardison receives a letter Nate wrote earlier in the day which outlines the three things the plan needed to succeed (which Hardison's plan made possible). Nate then explains how he plans his cons to anticipate the possibility of spanners; he starts with the crude, ugly basic plan, and then plans the elaborate, beautiful, intricate plan from there.
 * In the two part Buffy the Vampire Slayer episode "What's My Line", Spike (who, by the way, has killed more than one Slayer in his career) seems poised to cure Drusilla's curse, which requires using her sire - Angel - as a sacrifice in an unholy ritual. Since he doesn't have time to deal with Buffy while this is happening, he hires three members of Order of Taraka, assassins who never fail to fulfill a contract, placing the contract on Buffy. All seems to be going as he planned, the members of the Order managing to overpower Buffy as the ceremony is in progress. The Spanner? Kendra. Much like Buffy herself, Spike had no idea it was even possible for their to be a second Slayer, and he proves woefully unprepared to handle two at once. The episode ends with the ritual failing, the three members of the Order dead and Spike totally pulped and humiliated.

Music
"So I broke into the Palace With a sponge and a rusty spanner"
 * Invoked, if only as pastiche (which Morrissey adores, as we know) in The Smiths' title track "The Queen is Dead":


 * ...referencing a peculiar event—long forgotten by most, perhaps—though the unlikelihood of Michael Fagin's misadventure conveys this trope's inherent flavor of the unexpected. In the BBC's retrospective, we learn "[t]he Queen was only able to raise the alarm when he asked for a cigarette." In more security-conscious days, who'd imagine such a Royal contretemps could occur at all?

Tabletop Games

 * In just about any Dungeons & Dragons module, the adventurers are the Spanner. And any good GM has to be able to handle a Spanner, as the PCs can be expected to do the one thing the GM hasn't anticipated.
 * A mediocre GM can do this to players. When the players have a good plan which bypasses the intended challenge handily or solves a challenge with minimal fuss, a good GM may let the players have their moment in the sun and save those encounter notes to recycle them with new window dressing. A mediocre GM will have the players' plans fail for increasingly implausible reasons. A poor one will have a deer in headlights look as soon as the players are Off the Rails.
 * Example: Give the PCs the Eye of Vecna, you get some fun people fighting over it. However, one of the PCs sacrificing the Eye of Vecna to THE GOD OF JUSTICE? Not so expected.
 * In Unknown Armies, you can become an Avatar of an archetype by mimicking that archetype's classical behavior. One of those is The Fool, who can pull this off easily and walk away unscathed.
 * In Chrononauts, new players are the spanner. Plans in the game range from Gambit Roulette to "I win next turn as long as no one makes a minor change in 1914". New players will often meddle with history (even starting World War III), steal random historical artifacts, or kill the makers of said artifacts, to "see what happens".
 * In Exalted, beings that exist outside of fate are the ultimate Spanners from the perspective of the Sidereals. Since they cannot be detected, manipulated, or predicted by fate and fate-based powers, one of these beings can derail centuries of careful planning before the Sidereals realize that anything's amiss.
 * In Vampire: The Requiem, the Circle of the Crone has the position of The Fool, whose sole purpose is acting as this. When the Circle needs something stopped they send in The Fool and watch stuff blow up. Basically it's like "so, you're a rather spirited walking corpse, eh? Say, could you go check out what that Invictus bastard is doing downtown? Just do whatever feels natural, I'm sure it'll be a blast." Fools who survive long enough to gain some measure of respectability might make it to the rank of Trickster, for whom the purpose is basically the same except the Trickster actually has some idea of what he is doing.
 * A common meme in Warhammer Fantasy Battle and Warhammer 40,000 is to label the defeat of Tzeentchian and Eldar forces as "Not As Planned"; as the smug bastards claim any victory is "Just As Planned".

Theatre
"Cyrano: (Bowing to Roxane): Then I fought, happy chance! sweet lady, not For my ill favor—but your favors fair!"
 * Cyrano De Bergerac: Played hilarously straight: This play (a farce) has a lot of Gambit Pileup orchestated by Cyrano, Roxane and De Guiche, but no one of them is capable of being an Unwitting Pawn for long.
 * Cyrano: Lampshaded by himself at Act II Scene VI: Unaware of it, he destroys De Guiche plan to set an arranged marriage with Roxane and De Valvert when he manipulates De Valvert to a duel.


 * De Guiche: When you apply Fridge Logic, you see that De Guiche was the Unwitting Instigator of Doom in his own plan to bully Roxane into a marriage with De Valvert at Act I Scene IV: When De Guiche makes a Dare to Be Badass to De Valvert, it’s only a small act, but it’s crucial because it sets a Disaster Dominoes scenario that ends with De Valvert being touched by Cyrano and so unable to marry Roxane. He also destroys his own plan to Buy Them Off Cyrano when he mentions that his uncle Richelieu could correct a line or two from Cyrano’s work.

Video Games
"GLaDOS:"
 * In Grandia II, this role goes to Millenia. The Big Bad's plan requires What the villain didn't count on was
 * In The World Ends With You, Neku points out to a Manipulative Bastard that it is utterly impossible to predict what Beat is going to do. Heck, if you collect the Secret Report after the end of the game, even
 * Persona 3. After his Reveal as The Chessmaster, plans to sacrifice most of the party by  in order to bring about The End of the World as We Know It. He's just about to succeed... but at that point, the player is reminded that he forgot to crucify the dog, too.
 * "And I would have gotten away with it, too! If it weren't for you meddling kids and that dog!
 * 's ultimate scheme in Apollo Justice Ace Attorney was meant to be the murder of via a poisoned postage stamp depicting the magician act Troupe Gramarye. However, the girl is such a huge fan of the Troupe that she saves the stamp for seven years;  eventually uses the stamp instead and dies. The flaws in 's plans run deeper than this, but this is his only apparent mistake; everything else is because of 's meddling.
 * Larry Butz also counts, owing to his tendency to do unreasonable things that end with him stumbling onto vital evidence. In the first game, he, in the third he and then in a later case his choice to  leads to him witnessing a number of things he wasn't meant to.
 * In the fourth case of Justice For All, the lead that helps Gumshoe and company track down Shelly de Killer is, of all things living and not living,.
 * In the third case of Justice For All, Then you realize that
 * In the final case of Ace Attorney Investigations, the shenanigans of  end up helping Miles Edgeworth put away the seemingly untouchable Big Bad..
 * Larry gets to do this again in the manga. Simply by being arrested on suspicion of killing Bright Bonds (based on calling him and demanding that he get out of his ex-girlfriend's life), he derails the killer's plan to.
 * "All right, chums, let's do this! LEEEEEEEEEEEEEEEEEEROOOOOOOOOOOOOOOOY JEEEEENKINS!".
 * More of a subversion, as the "plan" was idiotic and wouldn't have worked anyway.
 * And the whole thing was staged as a satire of such silly and contrived "plans" anyway.
 * In Wrath of the Lich King, after Drakuru plays you for a Unwitting Pawn, you get to do this to his plans repeatedly. Revenge is so sweet...
 * Xenosaga:
 * A much more minor, but hilarious, example comes from Chrono Trigger. Ozzie, inept sidekick to the great Magus, was originally defeated by being dropped down a Trap Door. In his second coming, he's smart enough to make the switches instead drop the heroes down the trap door. When they come back, Ozzie's ready for anything... except for a random cat, which wanders in, flips the wrong switch, and down he goes...
 * It's one of Chrono's cats, scattered through time in the last ending, and is there specifically to help its master (Alphador is one of Chrono's cats too).
 * In Soul Nomad and The World Eaters, Lujei Piche apparently is stated to have ruined the effort involved
 * Revya and Gig, for all the multiple times they are Unwitting Pawns during the storyline, also become epic spanners:
 * Final Fantasy IV offers a minor example in the Dark Elf. A monster who messed up Golbez's plans to steal the Earth Crystal from Troia by snatching it first and running off to a cave where he rendered metal weapons unusable. Golbez works around this by sending protagonist Cecil to fetch the crystal in exchange for Rosa.
 * Believe it or not, Vaan from Final Fantasy XII fits this role very well. While he appears to be simply a throwaway character, he is the only one besides to . This implies that  felt that he would be a suitable and effective 'Plan B' to, probably due to his being both Dalmascan, and for, at the start of the game, harbouring resentment towards Archadia for the death of his brother. Ironically, Vaan actually overcomes , ultimately providing a more virtuous role model for , as seen when he refuses to take revenge on  for killing his brother. He may just have been the push she needed to reject revenge at the story's climax.
 * It's not so easy to see because it's a minor villain, but the Dark Elf King Astos has been at his plot for years, then the Warriors of Light come out of nowhere, on a completely unrelated quest, and straight up murder him. And while it might seem like Astos spanned his own plot, his theory was that the artifacts he tricked the Warriors of Light into getting him would make him all-powerful, so revealing himself isn't stupid so much as Genre Blind.
 * Dissidia 012 also retcons it that at least 1 Warrior of Light is a . This guy is such a spanner that he manages to bring down plots in 2 worlds without even knowing his own name, let alone his ridiculously improbable origin story.
 * Ash DragonBlade's story in Dragon Fable from Artix Entertainment consists of Ash foiling the plots of would be Big Bads through his own sheer stupidity.
 * In La Pucelle Tactics the plans of both Noir and are foiled not by the Maiden of Light, but by Priere, a newbie priestess who is perhaps the least likely person you'd expect being a nun, though she has a mean right hook and an even meaner set of legs.
 * In Final Fantasy Crystal Chronicles Echoes of Time,
 * In Evil Genius, this can easily happen to the player if (s)he gets careless. Even the lowest of the agents of justice can become the Spanner in the Works if you neglect to pay attention.
 * Ditto Dwarf Fortress; the tiniest breach in your defenses (like a monarch butterfly flying into the main door and jamming it open) can lead to goblins cutting a swath through your dining hall, or a fortress-wide tantrum-spiral.
 * didn't expect one thing in Modern Warfare 2.
 * In Star Wars: The Force Unleashed, the cunning plan created by fell apart due to one bit of (bad) luck and one unforeseen relationship. The accidental  resulted in a Heroic Sacrifice, and the emotional connection between Juno and Starkiller meant she came back and
 * The Alien protagonist in Aliens vs. Predator 2.
 * In BioShock (series), both and Sofia Lamb end up being thoroughly screwed by the . Andrew Ryan was right; the weak do not hold back the strong, the weak just
 * In the case of, becomes the very thing that leads to 's downfall.
 * In Mega Man ZX, the cornerstone of Master Albert's plan to become a god involved gathering the world's Model Ws and combine them into Ouroboros. However, aside from shitting out Mavericks like an Ominous Ring Of Land, it has no way to prevent an airship from crashing into it and inserting a war party intent on shutting him down. If he had a few more Model Ws, he could have sprung for mounted anti-air... too bad the Guardians (and Mega Man Model ZX) got to them first (and subsequently destroyed them). The thing to note is that this is a Spanner entry because Albert's plan would have been more complete had they not been destroyed; everything else went just as planned.
 * Actually the better example is how a pair of excavators accidentally awaken Grey, . After witnessing what Model W can do, Grey ends up saying no to Master Albert's plan and becomes instrumental in his downfall. Ashe also counts since in her storyline, she encounters Model A by accident and singlehandedly ruins Albert's plan as well.
 * Albert even notes that her appearing was entirely unpredicted, and the amount of trouble she caused for him surprised most people directly involved.
 * Sora and Co. from Kingdom Hearts have an innate ability to utterly ruin the numerous complicated plans that people form around them without having the slightest clue of what's really going on.
 * Team Fortress 2 - While the Spy's entire job is to be the Spanner in the enemy team's works, random chance tends to play this role in otherwise evenly matched teams, as nobody can account for that stray lucky critical hit.
 * And then there are the Griefers, who purposely sabotage their own team's objectives For the Evulz.
 * The protagonists of Silent Hill tend to be played for Unwitting Pawns—but they will also send the bad guys plans spiraling into complete disaster because their goals don't involve unleashing an Eldritch Abomination on the world.
 * Fear 2: Project Origin has this happen to the player instead of the villain. Terry Halford comes up with a telesthetic amplifier that could give the player character, Sergeant Beckett, a decent chance at exploding Alma's head, and then
 * In Vampire: The Masquerade Bloodlines, the player character skews the very, very delicate power balance of Los Angeles simply by being Embraced. That's about the only time things are not going according to someone's plan, though, and is directly followed by Xanatos Speed Chess on the part of Jack, LaCroix and, rather than a Villainous Breakdown on anyone's part.
 * King's Quest VI: Heir Today Gone Tomorrow: Grand Vizier Abdul Alhazred has been running an Evil Plan very successfully on the Land of the Green Isles. Gain the trust of the king and queen and their approval to marry the princess, making sure he's in charge. Spread rumors and encourage in-fighting among the islands to being the kingdom to the brink of civil war  . As the final piece, arrange a grand   wedding to the princess  . It's running like clockwork, and then the Prince of Daventry shows up with a mad crush on the princess...
 * Speaking of Sierra, the Hero in the Quest for Glory series tends to be this at times as well, either by intent or accident. Basically all of Quest for Glory IV was a result of the teleport spell used to snatch him at the end of Qf GIII dumping him in the wrong place in Mordavia.
 * Fire Emblem 7 has  and  . The first one ruins a Smug Snake magic user's trap for the heroes , the second is such a strong support for Eliwood that   has to admit that his mere presence throws his gambits around Eliwood off.
 * The Big Bad of Last Scenario had such a good plan going until . Then just happened to run into an Unwitting Pawn and warned him not to trust an agent of said Big Bad. Things kinda fell apart from there.
 * The is basically all the Boss does in Saints Row 2. The Brotherhood originally planned on bringing in a shipment of weapons to take over the city with. Boom, the Boss steals it all. Then they try to manipulate their friends out of jail. The Boss just kills all of them when they get out. The Sons of Samedi see their plans to sell drugs ruined by the Boss when he kills all their dealers, and when a lieutenant tries to trick the Boss into walking into traps, the Boss kills them too. Vogel, meanwhile, planned to manipulate everybody into killing each other so he could take his place at the top, which worked fantastically when he was getting the Boss to kill people instead of getting people to kill the Boss.
 * Raphael Sorel, the French fencer from Soulcalibur II, unintentionally saved the world and Siegfried (here in his guise as the Big Bad, Nightmare). Raphael appears as Nightmare's opponent in his Destined Battle. When Nightmare defeats Raphael and is about to finish him off, Siegfried is somehow roused out of his suppression by Soul Edge/Inferno and begins a Battle in the Center of the Mind, rendering his body immobile. Seizing the opportunity at hand, the injured Raphael takes his rapier and delivers a mighty thrust to Soul Edge's eye, weakening the soul of the sword and allowing Siegfried to fully regain control of his body. At that point, the holy sword Soul Calibur appears to aid Siegfried, who then plunges it through the evil sword again. This causes both swords to fall silent (having been locked into a state that rendered both dormant), setting up the plot of III and Siegfried's character progression to that of The Atoner. Raphael's reward? He gets infected by Soul Edge's malevolent influence (he unwillingly passes this on to his adoptive daughter Amy as well, when she tends to his wounds) and becomes some sort of vampire.
 * Half-Life 2 gives us the memorable line: "The Right Man in the Wrong Place can make all the difference in the world. So wake up Mr. Freeman, wake up and smell the ashes..."
 * In the Portal series' supplemental material, it's revealed that protagonist Chell wasn't originally intended to be a test subject, but a paranoid-schizophrenic researcher "volunteered" her on account of her psychological profile revealing near-pathological tenacity. Naturally, Chell is the one who takes down GLaDOS and is very nearly responsible, albeit indirectly, for the complete destruction of the Aperture Science Enrichment Center. Twice.


 * In Advance Wars 2, despite Andy having a spanner himself,
 * In the chapter 1 finale of Dragon Fable, the Big Bad is undone by two spanners. gives the hero and his dragon a fighting chance in the Final Battle. Just when it seems like even that wouldn't be enough to save the day,
 * Grim Grimoire has the The Archmage preparing to break free from his Soul Jar and take the philosopher's stone and menace the world, and powerful devil he entered a pact with named Grimlet is about ready to break from being sealed inside the old wizard Gammel Dore. Neither of them could possibly predict that both of their plans would screwed up by one Cute Witch named Lillet Blann caught in Groundhog Day Loop.
 * In The Elder Scrolls V: Skyrim, the Dragonborn can derail the longterm evil plans of several villains just by showing up and being a Badass. The Thalmor Dominion's long-running scheme to weaken their enemies can be completely dismantled by an unsuspecting  Dragonborn who singlehandedly ends the war  In the Thieves' Guild Questline,  plans didn't take into account the possibility of someone like the Dragonborn showing interest in joining the Guild. The villains behind the "Laid to Rest" quest in Morthal get totally screwed by two Spanners: the ghost of a little girl that one of them killed, and the Dragonborn who stumbles onto their plot while investigating the ghost girl's presence.
 * As of BlazBlue: Continuum Shift Extend, Terumi's master gambit pileup for his goals remained untouched up until
 * In Kingdoms of Amalur: Reckoning, The Fateless One is this to everyone and everything because he/she is Immune to Fate. Furthermore, since he/she was a Blank Slate with no memories upon revival it's impossible to predict just how he/she will react in any given situation. Everyone who tries to manipulate the Fateless One for their own evil plans fails miserably.
 * The evil scheme of Pokémon Black and White goes off the rails the moment, purely by encountering the player character in the second town.

Web Animation
"Kurama: "...so I believe Hiei's superior speed would be the best choice for this fight." Hiei: "Well Kurama, your plan sounds good except for one fatal flaw." Kurama: "What? What are you talking about? My plan is foolproof!" Kuwabara (screen-shift): "Here kitty kitty!" Kurama: "I stand corrected.""
 * In the Homestar Runner holiday toon "A Death-Defying Decemberween", Homestar announces to one and all that he's going to sled down the Steep Deep - a vertical cliff face - and Strong Bad catches The Cheat surreptitiously helping Homestar bury a mattress at the foot of the alleged slope. Of course, Strong Bad being Strong Bad, he moves the mattress expecting Homestar to maim himself on impact...but the next day, when Homestar sleds down the Steep Deep, he makes a perfect landing. As it turned out, the mattress was full of "hammers, broken glass and candy canes sucked down 'til they're all pointy"; the whole thing was a ridiculously elaborate (and painful) scheme for Homestar to get out of having to spend Christmas with his girlfriend Marzipan's parents, one that Strong Bad successfully sabotaged (even if the end result wasn't quite what he had been expecting).
 * In Yu Yu Hakusho Abridged:

Web Comics
"You always overthink things. The reason your plans keep failing is not because your enemies are geniuses. It's because they are idiots. A plan is only truly foolproof if you consider the fool."
 * In the Sluggy Freelance story arc "GOFOTRON Champion of the Universe," Zorgon Gola has a pretty nice Gambit set up where he pretends to be an Omnicidal Maniac, so that the heroes will sacrifice themselves trying to prevent a chain reaction that would destroy the universe, leaving him free to take over the Punyverse after their deaths. What he didn't count on was Torg, Riff, and Bun-Bun accidentally teleporting themselves into the Punyverse. They end up hijacking a vital piece of the heroes' Combining Mecha (the crotch). Without this, the heroes have no way of pulling off their Heroic Sacrifice, and Zorgon Gola, along with the rest of the Punyverse, is blown up. Oops.
 * Obi-Wan and Qui-Gon end up doing this to in Darths and Droids. In a clever little inversion, this whole scenario is actually made up on the spot by the DM, after the events took place in which the players apparently screwed up everything by going Off the Rails. The author suggests this technique as a way of getting back at players who mess with your established scenario too much.
 * Quentyn Quinn in Tales of the Questor is a subversion. Instead of stupidity, it is a sense of honor and desire to help that make him accept quests which almost always indirectly monkey-wrench someone's plans, generally without even knowing it. Examples:
 * A simple lack of knowledge led him to believe (and say) that human coins were forged. A politician's Oh Crap moment led a guard to realize they were indeed fakes—and who was behind it.
 * His very decision to become a Questor—paired with the discovery of an old contract—puts his home village in peril. The contract stated that the previous Questor was to retrieve some artifacts in exchange for land on which to build a village. The problem: the old Questor failed to do so, and now that there's a new Questor, a political faction intends to use that contract to get Freeman Downs reposessed and thus out of the picture. Quentyn's decision? Retrieve those artifacts, knowing that if he dies in the attempt, the law ensures that the contract ends with him. He knows nothing about the true scheme at work, and the opposing faction has no idea what to do now.
 * His desire to help a human village ended with him in a position to utterly screw over a fae--which he does so very epically.
 * And then there's Squidge, who is only too happy to prove that one can deliberately be a Spanner in the Works when he ruins Rahan's prank.
 * Fighter of 8-Bit Theater is the living embodiment of this trope, as he's too stupid to know whether he's supposed to fall for a crazy plan or not. He bends the Theory of Narrative Causality by his very existence.
 * Roy Greenhilt of The Order of the Stick might qualify for this in one early instance, despite being a very intelligent person, simply because he does something so very unexpected. Xykon honestly doesn't expect the heroes to stop him (and rightly so, as he has an army of monsters, 10 or more levels on the strongest PC, and a monster strong enough to send Paladins flying by lightly tapping them). He has three characters immobilized, two more being stalled by monsters, and he had just shattered the leader's ancestral sword. Confident that the battle is as good as over, he starts to call out the aforementioned monster to finish the heroes off. And then Roy goes and tosses his bony ass into a body-destroying gate that holds an Eldritch Abomination at bay. The Big Bad is out of commission.
 * Elan seems to fit this more than Roy does. Daigo at one point wonders if he's more useful the less he knows what's going on, and Durkon suggests that "He has Ignorence as a class power source." In 691, Roy lets him wander around the desert in the hopes that he'll stumble over something. WHICH HE DOES!
 * Antihero for Hire's Wizard lays it out cold for would-be Chessmaster Hector:


 * In Dead of Summer, the Big Bad's backup plan to blow everyone up with a Time Bomb was thwarted because
 * The majority of the plot of Demonology 101 consists of Raven and her friends following this trope.
 * One of the characters in the Blip is this to
 * The main cast of Drowtales are Manipulative Bastards and Chessmasters whose plans often wind up crashing into each other, but so far the biggest example of this trope is . If it weren't for her things in the story would be much, much different, and the full extent of her spanning potential is just beginning.
 * A smaller version in Girl Genius—British spy/Gil's man Wooster just caused  to go thoroughly off the rails.
 * An Eerie Cuties story starts with Alpha Bitch Melissa intending to enact "Operation Break Up" between Layla and Kade. As she explains to her Beta Bitch accomplices, trying to seduce Kade in front of Layla isn’t going to work, because Kade is a Chick Magnet and she has caught him in such situations a lot, and Clingy Jealous Girl she may be, she is very willing to forgive Kade for any acts of infidelity. Thus, Melissa decides on the opposite approach, seducing Layla in front of Kade, and then act as comforter to him later. However, Melissa surmises they can’t trick another male student into doing so (any student stupid enough to be so tricked would be too stupid to pull it off), so one of them has to do it herself - but Layla is not bi So, the plan is… one of them uses artifact called the Tiresias Orb (which can Gender Bend a person) and do it themselves. However, this plan hits a serious snag while they’re arguing over who has to swap genders (and Melissa assuring them it’s - probably - reversible); Blair (a living doll possessed by the spirit of a Dirty Old Man) hears their plan and grabs the Orb, then starts to enact his dream of creating a World of Buxom.

Web Original

 * When Tipping Forties LP'd Tales of Symphonia, they managed to go about 90 videos without using Presea, who they perceived as The Scrappy. The point was they hated the flatness of the character and refused to involve themselves with how stupid that part of the game was. Of course, they forgot the game was stupid (for that one instance, at least) and a scripted event forced them to use her. It nearly brought them to tears.
 * And it was Hilarious.
 * In the Whateley Universe, this is Jade's purpose in life. She's screwed over at least four plans, simply by being there. See "It's Good to be the don", "Christmas Elves", "Christmas Crisis", and Ayla 7-6.
 * It's extremely rare for this to not happen at least once per game in Comic Fury Werewolf. It also happens intentionally a surprising amount, considering.

Western Animation
""I'm not really that stupid. I purposely sabotage Brain's plans because if he ever succeeded, the show would be over, wouldn't it?""
 * Pinky of Pinky and The Brain is the downfall of pretty much all of Brain's schemes.
 * Brilliantly subverted in one episode, where Pinky convinces all of the world's leaders to hand over control of the world to Brain on a silver platter, only to have Brain himself torpedo the plan.
 * There are several occasions where it's Brain's own oversights that doom his plan (the Jeopardy episode where he blew the last question due to it being a pop culture one, as an example. And Pinky is completely obsessed with the show the Final Jeopardy question is based on. If only Brain listened to him...
 * There's also the episode where Brain builds a machine to calculate exactly what common factor keeps causing his plans to go wrong. Sure enough, the catalyst is not Pinky, but Brain himself.
 * Which raises the question of how Brain could fail to be a common factor in all of his own schemes.
 * Lampshaded in a Kids' WB! promo for the show, in which Pinky confesses:

""Choke on that, causality!""
 * In the Rugrats episode "The Bank Trick, Tommy and Chuckie mistake an ATM machine at the bank for an M&M machine and think the bank is actually a candy store. They don't find any, but they do inadvertently trip a security alarm and expose two bank robbers posing as federal bank inspectors.
 * Deedee from Dexter's Laboratory is almost always the one to ruin her little brother's scheming. Dexter turns this into Flaw Exploitation when he learns about his Arch Enemy Mandark's crush on Deedee, and turns her loose in his lab.
 * Coop of Megas XLR does this constantly. Prime examples: he once destroyed a planet-eating monster by firing an EMP-missile-turned-fridge packed with Pop Rocks and Coke, and in another episode he destroys the Glorft mothership by accidentally beaming his slushie onto one of its control boards.
 * Not to mention all of the times he's done it to himself and other goodguys.
 * Bullwinkle, of Rocky and Bullwinkle, is an idiot whose sheer stupidity endlessly frustrates villains Boris and Natasha.
 * Inspector Gadget is a perfect example, as he often inadvertently helped Penny and Brain solve the cases through his clueless bumbling:
 * Penny and Brain are trying to prevent a nuclear missile from being launched at Metro City, but it's taking too long and the countdown has started. We then see Gadget wandering through another part of the MAD complex, where he damages some important equipment. This aborts the countdown and gives Penny and Brain the time they need to disable the missile.
 * Gadget is swallowed by the robotic Stock Ness Monster that Dr. Claw has turned loose in an important lake, and he proceeds to start messing around with its inner workings. This causes the monster to go haywire and start swimming around the lake at random, which allows Penny and Brain to get inside of it and take control themselves.
 * Gadget is surrounded by MAD agents in a cave, and tries to get away by using his Gadget copter. The copter's rotor blades become stuck in the cavern ceiling and cause Gadget to start spinning out of control. His Gadget arms and legs start flailing around, pummelling the MAD agents and knocking them senseless.
 * Some MAD agents are about to spray a toxic wood-rot formula over a forest from an airplane. Penny tries to use the woodrot formula to knock a tree onto the runway to keep the plane from taking off, but the spray nozzle clogs and she only sprays enough to weaken the tree. Along comes Gadget flying in the Gadget copter, and he crashes into the weakened tree just as the plane is about to take off, knocking it over and stopping the plane dead in its tracks.
 * And then there was the time Gadget was in one of Dr. Claw's undersea bases, and opened the seal that kept the place from being flooded...
 * Gadget is pursuing a MAD agent in the Gadgetmobile, and Dr. Claw arrives in the Mad Mobile to try and stop him. In trying to catch the MAD agent, Gadget repeatedly activates the wrong gadgets, unknowingly spraying Dr. Claw with laughing gas and then firing a missile at the Mad Mobile that leaves it trapped in glue and unable to stop Penny from taking control of the MAD agent's vehicle to finally capture the villain.
 * MAD has taken control of the new supercomputer that the Metro City Police Department uses to coordinate its efforts to fight crime. When Gadget tries to use the computer to contact Chief Quimby, he thinks that the machine is broken and tries to "fix" it. He inadvertently wrecks MAD's connection over the computer, and then alerts the police to what's going on, enabling them to catch all the MAD agents who were committing crimes while the police were distracted.
 * Gadget is in a Spot the Imposter situation with a MAD spy who's disguised exactly like him. No one can tell which Gadget is real until our hero stands next to Chief Quimby. Gadget's mallet activates by itself and bonks Chief Quimby on the head, and the dazed Chief immediately orders that the other man be arrested, since the one who hit him is obviously the real Gadget.
 * Beavis and Butthead, of all people, pull this off in the movie Beavis and Butt-Head Do America. In the hope of "scoring", the dimwitted duo travel to Las Vegas and foil a criminal terrorist plot without realizing it.
 * Used explicitly and spectacularly in the second C.A.K.E.D. episode of Codename: Kids Next Door. At the episode's climax, Nigel responds to the Delightful Children's five-person-unison speech about having planned every last detail by declaring that they forgot one thing: "MY CRAZY GIRLFRIEND!"
 * The Flying Brains of Futurama intend to collect all the information in the universe and then destroy it, using their telepathic powers to keep anyone from stopping them. But they didn't count on Philip J. Fry, the one man in history too stupid for those powers to affect.
 * It wasn't because he was too stupid. It's that the unique mental condition that saved him also caused his stupidity.
 * But surely his stupidity contributed to his decision to do "the nasty in the past-y"—thus bringing about the circumstances that gave him the unique mental ... my head hurts.

"Batman: He anticipated everything I would have thought of, but who could anticipate you?"
 * Ron Stoppable of Kim Possible.
 * And when the bad guys remember to account for Ron, out pops Rufus.
 * In one episode Dr. Drakken goes so far as to leave Kim's father out of his gathering of geniuses-to-turn-idiots. When demanded to tell him why, Drakken states its because he realized kidnapping him would just get Kim's attention.
 * He didn't count on his scheme being right next to the ranch run by Kim's uncle and her, Ron and her father being there on vacation at the same time, though.
 * From the Justice League episode "A Better World": An evil alternate universe Justice League has captured the "real" League. Their Batman designed inescapable prisons for each Leaguer, because he's Batman. The Flash manages to escape by speeding up his heartbeat so it looked like he flatlined, and when the other Batman unlocked the cell, Flash beats him up at super speed. Lampshaded by our Batman:


 * In Turtles Forever, Ch'rell's ultimate plan is ruined by
 * Jar Jar Binks is even more of a Spanner in Star Wars the Clone Wars then he was in the original movies.
 * GIR the Cloudcuckoolander robot from Invader Zim.
 * The South Park cast finally decide to ignore Cartman after he eats the skin off the KFC chicken. Cartman thinks he died as no one communicates with him and Butters is the only one who can see him. A psychic explains that he is stuck on Earth to deal with a crisis. After learning of a hostage situation, Cartman believes he is the only one who can help. Believing he can't be harmed, he freely walks into the Red Cross Center and pretends to be a ghost while moving items around. The robbers don't know what to do and the police move in once Butters frees the hostages. The two are credited for saving the day "armed only with the weapon of confusion".
 * Avatar: The Last Airbender: Long Feng's plan to trick Team Avatar into leaving Ba Sing Se would have worked out perfectly if Smellerbee and Longshot hadn't just happened to cross their path and inadvertently reveal that
 * In Rated A For Awesome, Team Pet Mr. Twitchy is just as much a hindrance as he is helpful.
 * While Candace Flynn isn't evil, her attempts to show her mom what Phineas and Ferb have done would be more successful if Dr. Doofenschmirtz's crazy inventions didn't inexplicably cause their projects to vanish.
 * Princess Celestia from My Little Pony Friendship Is Magic gets a Crowning Moment of Awesome by
 * Actually, this would probably be a better example of Out-Gambitted, as
 * Cedric in the second season of WITCH.
 * As deranged as some of Zordrak and Urpgor's schemes to steal The Dreamstone are, some of them almost do the job were it not for Sgt Blob and his soldiers' blundering. The odd occasion Urpgor plays an active part in a mission he usually proves to be just as detrimental.

Real Life

 * Greece might have been this in World War II. If they hadn't held off the Italian invasion that required Germany to help them, Operation Barbarossa might have been started earlier, and the invasion of Russia might have succeeded.
 * Even before surrendering to the Allies in 1943, Italy was probably as much a hindrance as a help to the Axis war effort through opening new fronts and then calling for German help. The desert war was another example, starting when Italy tried to invade Egypt from Libya and promptly collapsed to the British counterattack until Rommel arrived ... which, of course, meant Rommel wasn't on the Eastern Front.
 * Hitler himself may count. If he hadn't meddled with everything, thereby wasting resources (like the V2—great for propaganda, useless in warfare), the Germans might actually have had a chance. And that's not even counting that brilliant idea of attacking Russia.
 * Late in the war (1944–45) this became fairly explicit: The British cancelled plans to assassinate Hitler because they believed any replacement leader would be more effective, extending the war.
 * During the Battle of Midway, the Japanese were not defeated by any cunning strategy, but because a group of lost dive bomber squadrons suddenly stumbled upon the Japanese carrier group while it was rearming all its planes, making them extremely vulnerable.
 * In the first World War, Germany intended to go through neutral Belgium in order to attack the French. It probably would have worked if not for the Belgian resistance delaying them.
 * Worse than that for the Central Powers in the long run, Britain had no intention of entering the war until Germany invaded Belgium. If Britain had remained neutral, the US likely would have, as well, and it's quite probable Germany and Austria-Hungary would have won if their only sizable enemies were Russia (which collapsed in revolution), France, and Italy.
 * Even Italy was a toss-up, as it effectively waited to see which side would give the best offer until 1915. Italian designs on Austrian territory probably gives the edge to the Entente, but without the British involved the Central Powers might have had a chance.
 * Santa Anna's plan to finish off the Texas Revolutionaries at San Jacinto on April 22, 1836 was ruined by Sam Houston's decision to attack first a day earlier despite the Mexicans outnumbering the Texans 1,400 to 900. Santa Anna also sealed his own fate by diverting too many of his soldiers and failing to post lookouts while his army rested—not to mention supposedly getting seduced by the "Yellow Rose of Texas" Emily Morgan. The Mexicans surrendered to Sam Houston's assault after just 18 minutes of fighting.
 * If you're doing user interface design, one of the best tests is to hand the software to an entirely untrained user. They will ferret out all kinds of little bugs and quirks because they'll choose utterly ridiculous but nonetheless logical ways to use your application.
 * Similarly, video games. Less skilled gamers will find those accidental holes in the wall before experienced gamers, who aren't, you know, accidentally running into walls all the time.
 * Developers of the perl programming language have stress-tested new versions by having it parse /dev/random as input. Bugs that had resulted in segmentation faults were discovered this way.
 * This trope describes much of the history of economics. Even the most brilliant economic models and philosophies can break down because people are neither strictly rational nor in possession of "perfect information."
 * Professional poker players can sometimes be thwarted by novices and amateurs, who make plays that no professional would be stupid enough to attempt and end up short-circuiting the professionals' expectations. This also is true for billiards players.
 * And for chess players, if the neophyte makes a bizarre move during the Opening.
 * Not really, in chess it's almost impossible to beat a player who's above your level, this is because if the said neophyte makes a bizarre move during the opening it is most likely a bad move and that alone tells the good player that he's not against a strong opponent, also it's said that playing against someone who's way worst than you will dull your skills and it's highly advised to avoid doing so.
 * In the training of fighter pilots during WWII, the best students of all were made flight instructors. They generally were not sent to fight, because it was found that highly skilled pilots were more predictable and thus easier to shut down than someone who's slipping and skidding all over the sky.
 * A Canadian fraudster used a complicated scheme involving disappearing ink and forged cheques to embezzle thousands of dollars from the banks he held accounts at. It's difficult to explain briefly, but it involved him writing a cheque to transfer funds from an account he held at one branch to the account he had at another bank. The scheme depended on his cheques being cashed at the first bank on a Friday, then the ink disappearing over the weekend, and processed at the second bank on Monday, which would give him more money in his first than was deducted at his second. Unfortunately, on one occasion the fraudster had the bad luck of dealing with a rookie teller who didn't know how the cheque was supposed to be cashed, and didn't start working on it until Monday. The boss noticed the discrepancy, accused the teller of writing the information wrong, and called the police on her. The police discovered that the check had actually been written partially in disappearing ink, and the fraudster was quickly nailed.
 * His Accidency, John Tyler. To explain: "He was a longtime Democratic-Republican who was elected to the Vice Presidency on the Whig ticket" (from his description page). As this makes him a Whig In Name Only, one wonders about his drinking habits.
 * A couple of fraudsters decided to make large amounts of fake $20 bills, and in turns they bought food with those at McDonald's and other stores which worked so well they earned several thousands of dollars from the exchange money. Around half a year later they went to Las Vegas and gambled for a week without getting noticed... until one day a woman who had the weird habit of ripping the upper-left edge from the bills noticed the paper was white inside (they did not use enough ink). The couple wanted to leave but was quickly taken by security and in their apartment they had 4 four more boxes filled with fake money.
 * A version from The American Civil War: on the second day of the Battle of Gettysburg, Confederate General Lee devised a strategy to attack both flanks of the Union army simultaneously in hopes of overwhelming them before they could be reinforced by the center. General Sickles from the Union ignored orders and moved his corp out in front of his fortified position to engage the enemy, a move of staggering stupidity that got his corp massacred. However, this delayed the main Confederate assault on that flank by several hours, destroying any chance the Confederacy had of launching the attacks simultaneously. As a result the attacks went on separately, and were beaten back separately. This in turn led to Lee gambling desperately with Pickett's charge the next day, a disaster that effectively destroyed Confederate momentum in the war.
 * While people often "what if" this battle, it is pretty generally agreed that Lee did not do a very good job of commanding the battle in general, and there were far, far more problems than this one.
 * Thomas Blood's plan to steal the British Crown Jewels failed only because the elderly caretaker's son came back on leave from the navy at precisely the right moment. Seriously.
 * Vanessa Williams thought she'd never be able to live down the nude photos that appeared in an issue of Penthouse and cost her her Miss America title. Then it was discovered that the centerfold (guess who?) was underage, and the issue was banned along with most of the centerfold's filmography up to that point (with the exception of Traci, I Love You) as well as the porn industry ostracizing the centerfold in question entirely. Williams was supposedly relieved to see all those nude photos of herself go bye-bye over an underage centerfold appearing in the same issue as said photos.
 * This happened to Tennessee in their 2010 college football match against LSU. UT had the game won when LSU stupidly didn't have a play ready for a third-and-goal with seconds remaining and no timeouts, resulting in a botched snap that looked to end the game. But UT trumped it with their own stupidity in a last-second personnel change that resulted in Two Many Volunteers on the field (four guys came on while three ran off, and then one of the three ran back onto the field). The illegal participation penalty forced the down to be replayed (American football games can't end on a defensive penalty), giving LSU time to settle down and organize the game-winning play. You can watch the last moments of the Dumbass Miracle here.
 * Political parties in America are this, believe it or not. The government was set up so that all three branches — executive, legislative, and judicial — would be more or less in opposition to each other. The rise of political parties put paid to that in a hurry.
 * Indeed most of the founding fathers were completely against political parties, but viewed them as a necessary evil that would naturally arise despite their best efforts.
 * The Tea Party is this as far as many politicians are concerned. Just look at the 2011 US Debt Ceiling controversy.
 * It's interesting to note that each party plays this role to each other, but the tea party plays this role to both parties.
 * Jussie Smollett claimed to have been attacked with a noose, bleach, and blunt objects in a violent hate crime by a pair of alleged white, racist, homophobic right-wingers in the middle of Chicago. His story had more than a few notable holes, like lack of damage from the bleach and his refusal to share phone records that would back up his claims. (He also didn't say how they recognized him, but he was a working actor at the time.) The biggest problem however, and what turned it into a nation-wide laughing stock instead of quickly-forgotten alleged hoax, is the day he claimed the attack it was literally the coldest day in the history of Chicago. Pedestrian traffic was so clear the lack of anyone who could have been the attackers was obvious in camera footage, and it was so cold bleach would have frozen solid inside the container. After wasting the CPD's time with the highly publicized case, he was arrested him and charged with faking the attack with the aid of two black actors; all of the charges were subsequently dropped.