History Main / ForbiddenChekhovsGun

* ''VisualNovel/FateStayNight''. Specifically, using Excalibur, the first DeusSexMachina (maybe), Shirou's arm, taking on Caster/Kuzuki directly on their turf (not a dangerous ''technique'' but the strategy is essentially suicide) and projection in general. Maybe it would have been best to simply leave this with no details considering how prominent this is?

* In [[Better Call Saul]], the second season premiere is titled "Switch." This refers to a switch Jimmy sees in his office with a taped sign that reads "Do NOT turn OFF!" At the end of the episode, he peels back the tape and switches it. Nothing happens. He switches it back and puts the tape back on.

* In "Better Call Saul", the second season premiere is titled "Switch." This refers to a switch Jimmy sees in his office with a taped sign that reads "Do NOT turn OFF!" At the end of the episode, he peels back the tape and switches it. Nothing happens. He switches it back and puts the tape back on.

* The Evil Ring in the first ''VideoGame/{{Ys}}'' game normally kills you if you equip it. However, you later need to use it in combination with the Blue Necklace to access the area where Lair is imprisoned.

** ''Literature/DeadBeat'': Harry broke the Fifth Law of Magic when he reanimated Sue. His necromancy falls into a loophole and he is not prosecuted for it by the council since he did not use it on a human but it colors the council's opinion of him going forward.

* ''Fanfic/AncientSins'' has many moves and powers that are only to be used as last resorts, but the one that rank above all others is the spell invented by reformed ''BigBad'', Dante, which allows the user to fire all their magical power at the target. However, this can be fatal is used incorrectly, so Dante is the one who mostly uses it.

* Madoka in ''Anime/PuellaMagiMadokaMagica'' is essentially a Forbidden ChekhovsGunman. Kyubey repeatedly states that she'd have incredible, godlike power if she made a contract, but the other girls--especially Homura--keep preventing her from going through with it to spare her from a magical girl's life of tragedy. [[spoiler:Eventually, it becomes clear that her transformation would probably cause TheEndOfTheWorldAsWeKnowIt, because every magical girl inevitably becomes a witch if she lives long enough, and the most powerful magical girl would become the witch to end all witches. Homura ''knows'' this will happen; being a time-traveller, she's seen it firsthand ([[NiceJobBreakingItHero and is the major cause because the nature of her time-traveling actually makes Madoka's potential (and thus her Witch) even stronger]]). But Madoka eventually makes a contract in a way that avoids this inescapable downside at the cost of her needing to AscendToAHigherPlaneOfExistence.]]

* Madoka in ''Anime/PuellaMagiMadokaMagica'' is essentially a Forbidden ChekhovsGunman. Kyubey repeatedly states that she'd have incredible, godlike power if she made a contract, but the other girls--especially Homura--keep preventing her from going through with it to spare her from a magical girl's life of tragedy. [[spoiler:Eventually, it becomes clear that her transformation would probably cause TheEndOfTheWorldAsWeKnowIt, because every magical girl inevitably becomes a witch if she lives long enough, and the most powerful magical girl would become the witch to end all witches. Homura ''knows'' this will happen; being a time-traveller, she's seen it firsthand. But Madoka eventually makes a contract in a way that avoids this inescapable downside at the cost of her needing to AscendToAHigherPlaneOfExistence.]]

* Early in the Australian lawn bowls comedy (uh huh) ''Crackerjack'', Jack tries a "flipper" - in short, a cricket thing transposed to lawn bowls - with disastrous results. He's angrily told never to pull that crap again, but when he has to pull off an almost impossible shot in order to win the championship, he's explicitly instructed to do it.

* The Manhattan Project. Scientists did experiments seeing how close they could get radioactive cores to going critical without ''actually'' making them go critical. They called this [[TemptingFate Tickling The Dragon's Tail]], and considered it a necessary but insanely dangerous thing to do. One core did accidentally go critical (very briefly) on two separate occasions, resulting in the deaths of two researchers and less severe cases of radiation poisoning for several others. They dubbed this one the [[NamesToRunAwayFromReallyFast Demon Core]]. And of course, there are two cases where they [[NukeEm very intentionally let the cores go critical]], but that was the point. There was some speculation that the detonation of the first thermonuclear device ''could'' cause atmospheric nitrogen to start fusing, which would have made our Solar system a binary, briefly. Preliminary calculations indicated it was a long shot but didn't rule it out completely; the probability was deemed high enough that they actually got someone to do the detailed calculations to prove it wouldn't happen.
* Creating the Higgs Boson, a.k.a "the God particle" using the Large Hadron Collider was thought by pop culture to be an easy way to bring about TheEndOfTheWorldAsWeKnowIt and was the subject of quite a lot of controversy at the time. The Collider was activated on schedule regardless, and the Higgs boson's existence confirmed some years later, and if it destroyed the universe no-one has noticed.

Often used in conjunction with a GodzillaThreshold. Compare DangerousForbiddenTechnique. ''Mildly'' related to ExplosiveOverclocking, TemporalParadox, and FinishingMove.

* Aban from ''Manga/DaiNoDaiBouken'' developed [[DangerousForbiddenTechnique Grand Cross]] as a GodzillaThreshold skill. He specifically states that it's only intended to be used when everything else has been tried, which warns the viewer this [[ChekhovsGun skill]] will only be used at a story climax.

** During the TrainingMontage in ''Film/AntMan'', Hank warns Scott not to tamper with the shrink suit's regulator. Doing so would risk Scott going subatomic and effectively disappear. [[spoiler:Scott eventually does so as an intended HeroicSacrifice to slip past Yellow Jacket's titanium plating to destroy his suit]].

** In ''Discworld/TheColourOfMagic'', one of the '''eight spells''' from the Octavo (eight is an important number on the Disc) has lodged itself in Rincewind's mind. He doesn't know exactly what it does, but popular wizarding opinion is that it will destroy the Disc (especially if cast alone). As a semi-sentient entity, it tries to cast itself. Rincewind ''barely'' prevents himself from casting it several times through the course of the first two books (which is one story) ''Discworld/TheColourOfMagic'' and ''Discworld/TheLightFantastic''. [[spoiler:When he does lose control, a significant event is already happening and the seven other spells have been cast. At this point, it's '''not''' a spell to destroy the world... but to create others.]]
** In the back-story of ''Discworld/GoingPostal'', an automatic letter-sorting device with extradimensional components (it accesses a dimension where pi is exactly equal to 3) goes out of control, filling the Ankh-Morpork Post Office with letters. Wizards called in to inspect the device warn that shutting it down is likely to destroy the universe. Fed up with the machine, a veteran mail-carrier starts smacking the device with a crowbar until it shuts down. When the mail-carrier started hitting the device, the wizards ran away. As the doer of the deed testified, unless they had some other universe to run to, they weren't really sure about the danger. The wizards insist that the universe ''really was'' destroyed, but was instantaneously replaced by a complete, identical universe. [[spoiler: That exact thing has actually happened before in that series. Twice, depending on how you count.]]

* In the classic WesternAnimation/LooneyTunes short "Design For Leaving," Elmer's house gets rebuilt with all kinds of futuristic gadgets (which don't work right, naturally). Among them is "this [[VerbalTic wed]] one, wight here," to which Daffy the salesman responds, [[BigNo "No no no no!]] Not the wed one! Don't ever push the wed one!" [[spoiler: It's to escape tidal waves. It elevates the house hundreds of feet up into the air. When Elmer pushes it at the end, Daffy comes by in a helicopter to let him know that "For a small price, I can install this little ''blue'' button to get you down."]]

* In ''Series/BabylonFive'', the "Bonehead Maneuver" as mentioned in the Season 3 premiere. You have two ways of going in and out of hyperspace. If your ship is powerful enough, you can open your own jump point, or, if your ship isn't that powerful, you have a Jump Gate open one for you. You never want to open a jump point inside a jump gate, because this causes one massive explosion of a NegativeSpaceWedgie. Aside from the loss of a very hard to replace jump gate (typically a star system will have one at most) and potentially stranding people in the system if they lack massive starships, this doesn't actually cause any huge universe-altering affects. Just a huge explosion that is difficult for most ships big enough to open a jump point to [[OutrunTheFireball outrun]] (so not really a GodzillaThreshold). They end up using the trick in a tricked-out new spaceship that MIGHT be fast enough to get away after using this trick to kill an enemy they DEFINITELY weren't big enough to fight.

** In the ''Ride/MenInBlackAlienAttack'' ride, a BigRedButton like the one mentioned in the above example appears in every ride car. Like in the film, you are told never to press it. However, by the end of the ride you face a giant alien that's immune to your weapons. Guess what you have to do? A cheesy instruction video seen while in line on the ride explains exactly WHY you don't press the button; it's a ''nuke'' capable of frying the more {{Kaiju}}-esque aliens.

* At the beginning of the ''Comicbook/{{Supergirl}}'' arc ''ComicBook/RedDaughterOfKrypton'', the [[Franchise/GreenLantern Red Lanterns]] explain to Supergirl that she can never, ever, take her Red Lantern Ring off since she would die. [[spoiler:At the end of the story, Kara removes her ring to try to kill an enemy that was taking over her body.]]

* ''Film/TheFastAndTheFurious'': The Dodge Charger in Dom's garage belonged to his father and nobody, not even Dom, dares drive it... until the last ten minutes of the film.

* Happens again in ''VideoGame/GhostbustersTheVideoGame'', [[spoiler: except this time due to being in the ghost world - where the same rules of physics don't apply, such as the lack of gravity on the actual landmass - one can probably assume that you can [[ForbiddenChekhovsGun cross the streams]] without frying your ass to bits because the chances are ''reversed'', thus making it more safe to try.]]

* In the ''Ride/MenInBlackAlienAttack'' ride at Universal Studios, a BigRedButton like the one mentioned in the above example appears in every ride car. Like in the film, you are told never to press it. However, by the end of the ride you face a giant alien that's immune to your weapons. Guess what you have to do? A cheesy instruction video seen while in line on the ride explains exactly WHY you don't press the button; it's a ''nuke'' capable of frying the more {{Kaiju}}-esque aliens.

* In ''Literature/FoundationAndEmpire'', Devers is trying to escape Trantor, with the police in hot pursuit, since [[spoiler:he just killed a Lieutenant]]. He enters hyperspace very close to the planet, which could kill him. It is promptly indicated that doing a BlindJump like Devers did isn't actually all that dangerous, assuming you have enough supplies -- if you vaguely target empty space (Devers skimped on calculations, and the higher the gravitational pull, the more complicated the calculations), you have a very good chance of arriving in empty space. The problem is that it is ''only'' useful to desperately flee, since you then have to spend a lot of time figuring out where you are before you can travel anywhere. Doing a semi-blind jump ''to'' a system, on the other hand... [[spoiler: thus rendering this a cross-story Gun within the novel, since the protagonists of the second half of ''Foundation and Empire'' have to do exactly that]].

* The Higgs Boson, a.k.a "the God particle". The way to discover it ''could'' turn Earth into a black hole. Or cause the vacuum of space to drop to a more "stable" state, [[TheEndOfTheWorldAsWeKnowIt destroying the universe as we know it]]. [[ConspiracyTheorist Y'know, at least according to weirdos and pseudoscientists]].[[note]]We're now ''pretty'' sure the LHC has made several Higgs, and if it destroyed the universe no-one has noticed.[[/note]] [[note]] Nah, it just [[Literature/TheHitchhikersGuideToTheGalaxy disappeared and got replaced by something even more bizzarre and inexplicable]]. Again. [[GoodJobBreakingItHero I hope you're happy, you scientist-hippie types]].[[/note]]

* ''VideoGame/PressXToDie'' is a video-games-specific instance of this, in which the game will '''[[SchmuckBait really]]''' be over if the player actually fire the forbidden gun. Usually, the gun is some kind of weapon of mass destruction.