History Main / ForbiddenChekhovsGun

* ''WesternAnimation/MyLittlePonyEquestriaGirlsLegendOfEverfree'': Timber Spruce mentions from the get-go that the abandoned rock quarry is off-limit. Although it's perfectly logical for such a place to be considered dangerous, it naturally proves later to have a very important place in the plot.

* In ''[[Webcomic/TheInexplicableAdventuresOfBob The Inexplicable Adventures of Bob,]]'' from the moment Galatea learns about the [[GodzillaThreshold insanely dangerous]] forbidden Nemesite super weapon, the "Butterfly of Iron," it's pretty much inevitable that she's going to find and activate it.

* In ''[[Webcomic/TheInexplicableAdventuresOfBob The Inexplicable Adventures of Bob,]]'' from the moment Galatea learns about the [[GodzillaThreshhold insanely dangerous]] forbidden Nemesite super weapon, the "Butterfly of Iron," it's pretty much inevitable that she's going to find and activate it.

* In the Cone story in ''[[Webcomic/TheInexplicableAdventuresOfBob The Inexplicable Adventures of Bob,]]'' from the moment Galatea hears about the forbidden Nemesite super weapon the Butterfly of Iron, any savvy reader will realize there is virtually no chance of her ''not'' finding and activating 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.
* 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]]

* ''Manga/Naruto'' features the concept of the Eight Gates in the body that regulate a person's chakra flow. These gates can be opened and with each opened gate, the user of this technique becomes stronger and faster. This process [[HeroicRROD greatly damages the body]], however, and if the Eighth Gate is opened, the user will die. After years of Might Guy and Rock Lee gradually pushing this technique further, we get to see the Eighth Gate in action exactly once during the finale arc. [[spoiler: Guy uses it to (temporarily) become stronger than a Ten Tails-powered Madara Uchiha, and is only saved from death by Naruto.]]

* ''Anime/NarutoShippuden'' Introduces the concept of eight gates in the body that maintains the energy flow. These gates can be opened and with each opened gate, user of this technique becomes stronger and faster. This process greatly damages the body and if the 8th gate is opened, person dies. Guy tells his apprentice Lee never to open the 8th gate. In the final fight of the entire series, Guy ends up opening it.

* ''Anime/NarutoShippuden'' Introduces the concept of eight gates in the body that maintains the energy flow. These gates can be opened and with each opened gate, user becomes stronger and faster. This process greatly damages the body and if the 8th gate is opened, person dies. Guy tells his apprentice Lee never to open the 8th gate. In the final fight of the entire series, Guy ends up using it.

* In the ''Film/LostInSpace'' film, ships have hyperspace engines, but it is not a good idea to jump without coordinates or a jump gate as [[YouCantGoHomeAgain the exit vector would be random]]. The crew does this anyway when the ship is sabotaged and crashing into the sun.

'''Banner:''' That's my secret Captain. I'm always angry.

!!Examples

[[folder:Anime and Manga]]

[[folder: Comic Books ]]
* In ''TheFlash'' storyline "Terminal Velocity", Wally has various reasons to believe that pushing his superspeed too far is a GodzillaThreshold that will draw him into the Speed Force, never to return. He tries to avert a conflict which he knows will force him to do this, but to no avail. However, when he does finally enter the Speed Force, he manages to return (which no one has done before) thanks to ThePowerOfLove.
* In the ComicBook/{{Asterix}} comic series, Getafix does not allow Obelix to drink the magic potion, as he fell into the cauldron as a boy, and an extra helping could have bad effects on him. But in one story, ''Asterix and Cleopatra'' (both the comic book and the animated version), Getafix gives him just a drop of potion to give him extra strength in a difficult situation.
** Also overlaps with GodzillaThreshold.
** It's [[JustifiedTrope justified]]: a later book showed that if Obelix drinks a large amount of potion, he'll be [[TakenForGranite turned to granite.]]
* Fone Bone, Gran'ma Ben, and one of the Dreaming Masters were the only people who didn't want to do it, but near the end of ''ComicBook/{{Bone}}'', the Crown of Horns seems to be the only way out, even though it's been said that if Thorn even touches it, all of existence would be in jeopardy, and the trip there would be dangerous anyway with all the dragons that guard the Crown of Horns and intend to kill anyone who's anywhere near it.
** [[spoiler: Fone Bone improves their chances by not actually touching it, just grabbing Thorn's hand and ''almost'' touching it via static shock.]]

[[folder:Fanfiction]]

[[folder:Films -- Animated]]

* ''Film/{{Ghostbusters 1984}}'' has the iconic warning "Don't cross the streams," which they inevitably have to do at the end of the movie. As former TropeNamer, it was also causing confusion, since this overlaps with GodzillaThreshold. In this case, the non-disaster when they do end up crossing the streams makes internal sense: they are firing into a [[spoiler:ParallelUniverse EldritchLocation where a dark god trying to destroy the world is based, and presumably, [[InferredHolocaust the disaster Egon predicts happens]] '''[[InferredHolocaust there]]''' - and closes the gate]].

* In ''Film/TheAvengers2012'', the whole team (minus [[BullyingADragon Tony]]) spends a lot of time trying to keep Bruce Banner calm. Then the alien invasion arrives.
--> ''Alien leviathan starts heading towards the group.''
--> '''Captain America:''' Dr. Banner! Now might be a good time to get angry.
--> '''Banner:''' That's my secret Captain. I'm always angry.
--> ''Banner [[HulkOut Hulks Out]] and [[MegatonPunch punches]] the leviathan.''
* ''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.

* 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]].

* ''Literature/{{Discworld}}''

[[folder: Live Action TV ]]

[[folder: Tabletop Games ]]
* ''TabletopGame/{{Warhammer 40000}}'' gives us [[ArtifactOfDoom the Spear of Twilight]], which will doom whoever removes it from stasis to death from a wasting curse. Prince Yriel saved his Craftworld from being eaten by Tyranids by using it.

[[folder: Theme Parks]]
* 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.

[[folder: Video Games]]

* The first ''Franchise/{{Halo}}'' trilogy had you trying to prevent the Halos from going off. Guess what the last level of ''VideoGame/{{Halo 3}}'' has you doing? [[spoiler: It was only one Halo, not the whole set,]] but the concept remains the same. Cortana even handwaves it. The reason for trying to prevent that is that the Halos are meant to kill all life in the galaxy. [[spoiler: The one in the third game is outside the galaxy as noted in the first level on the Ark. One marine points out that the Milky Way is visible in the sky, meaning you're not in it.]]

[[folder:Webcomics]]
* This is the same way ''[[Webcomic/EightBitTheater 8-Bit Theater]]'' character Red Mage's Ice-9 spell (a reference to the novel ''Cat's Cradle'') works: as [[http://www.nuklearpower.com/2004/11/25/8-bit-chronicles-2-of-3/ the description]] puts it, it removes all heat from the universe it is used in, thus destroying all energy. He can only use it on other dimensions, like a bag of holding that he shoved an enemy in... which White Mage then smashed with a hammer.

[[folder:Web Original]]
* Played for laughs in ''Theatre/AVeryPotterMusical'' in which Harry shouts: "don't cross the streams!" when the [[PowerTrio trio]] summon their Patronus.
** And [[strike: Milfoy]] [[strike: Malloy]] [[strike: Count Chocula]] Malfoy. But the dialogue the Ghostbusters use is used in AVPM as well, though to dicuss why Harry has to compete in the House Cup tournament rather than beam-crossing.
[[/folder]]

[[folder: Western Animation ]]
* ''WesternAnimation/JohnnyTest''--Johnny teams up with some villains to save the Earth, and they're told right before they head out to not use their powers while holding hands, since it could multiply their powers by 500% or something. Naturally, when their plans are thwarted, they turn to this. It ''sounded'' like the villains refused to do this, and Johnny teamed up with his... dog.

-->'''Peter''': Egon, this reminds me of [[NoodleIncident the time you tried to drill a hole in your head]].
-->'''Egon''': That [[GoneHorriblyRight would have worked]] if you hadn't stopped me.

[[folder: Real Life ]]
* 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.\\
\\

* 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]]

* In the ''Franchise/{{Ultima}}'' series, the Armageddon spell (which kills everything and destroys the entire world when cast) has always just been used as a RedHerring to give the player a NonStandardGameOver, but by sealing oneself inside the separate universe made by a Barrier of Life spell with the BigBad in ''VideoGame/UltimaIX: Ascension'', the player is able to destroy just the universe he's in right now, along with his opponent and himself.

* 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]]

* The [[SuperPrototype Gunstar's]] [[SpinAttack Death Blossom]] attack in ''Film/TheLastStarfighter''; not so much that's it's insanely overpowered (although it is) as that it leaves the ship vulnerable just before and after it's engaged.

* In ''VideoGame/SouthParkTheStickOfTruth'', the hero swears an oath never to fart on a man's balls, and is discouraged from this multiple times throughout the story. However, [[spoiler: the hero is forced to fart on Zombie Nazi Princess Kenny's balls in order to defeat him.]]

* In the novel ''Literature/{{Foundation}} and Empire'', 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]].

* About a third of the way into ''Film/FantasticFour'' when the Four are running tests on their capabilities, Johnny gets so hot he melts the walls of the test chamber. Reed stops the test with fire retardant foam, then explains to him that he'd gotten [[SciFiWritersHaveNoSenseOfScale almost as hot as a supernova]] and that this was bad. [[spoiler:During the fight with Dr. Doom at the climax, Reed tells Johnny to go supernova inside Sue's forcefield to try and melt Doom.]]

* 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.

* When an instructor is teaching you to use a gun, whether or not it's for self-defense, the first thing they will teach you is to '''never''' point a gun at a human being, with the sole caveat "unless your life literally depends on it". This is of course to prevent IJustShotMarvinInTheFace. Sadly, not everyone listens.
** Variants include "Don't draw on someone you aren't willing to kill", and "Don't point it at anything you don't plan to destroy".

* 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 would 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.]]

* 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. [[spoiler:Eventually, it becomes clear that her transformation would probably cause TheEndOfTheWorldAsWeKnowIt, because she'd soon become the witch to end all witches. Homura ''knows'' this would happen; being a time-traveller, she's seen it firsthand. But Madoka eventually makes a contract in a way that prevents the cataclysmic downside at the cost of her own AbstractApotheosis.]]

* 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. [[spoiler:Eventually, it becomes clear that her transformation would probably cause TheEndOfTheWorldAsWeKnowIt, because she'd soon become the witch to end all witches. Homura ''knows'' this would happen; being a time-traveller, she's seen it firsthand. But Madoka eventually makes a contract in a way that prevents the cataclysmic downside.]]

* 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 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.]]

* Played for laughs in ''AVeryPotterMusical'' in which Harry shouts: "don't cross the streams!" when the [[PowerTrio trio]] summon their Patronus.

* At the beginning of ''VideoGame/Borderlands 2'', Claptrap tells you of a gun he keeps in his cabinet, but "only for emergencies." [[spoiler: There's an emergency.]]