Perhaps it's some sort of DoomsdayDevice or an ArtifactOfDoom maybe it runs on some sort of perpetual energy. Possibly there are actually two phlebotinum devices interacting with each other and destroying the world, but if you turn off one device the other one will grow strong enough to kill everyone on earth anyway. Perhaps it's a ClingyMacGuffin or ClingyCostume and it's draining your life force, but if you remove it you'll blow up. No Off Button is simply the reason a particular piece of dangerous AppliedPhlebotinum can't be turned off or destroyed, such as it lacking an off button.

FailsafeFailure is closely related, and involves examples where there is an "off button" or other form of Override Command in place, but it doesn't work.

!!Examples:
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[[folder:Anime & Manga]]
* In ''{{Naruto}}'', the Akimichi pepper pill puts your metabolism into overdrive, converting calories into tremendous power. But it keeps going even when your body has no fat left to use up.
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[[folder:Film Live Action]]
* ''Film/StarTrekIITheWrathOfKhan'', David Marcus helped build the Genesis Device.
-->'''David:''' It's the Genesis Wave! They're on a build-up to detonation! [snip]
-->'''Kirk:''' We'll beam aboard and stop it.
-->'''David:''' You can't.
* ''ForbiddenPlanet''.
-->'''Morpheus:''' Son, turn that disc. [[BigRedButton The switch.]] Throw it. In 24 hours, you must be 100 million miles out in space. [[SelfDestructMechanism The Krell furnaces]]...chain reaction...they cannot be reversed.
* The DoomsdayDevice in ''DrStrangelove'' will automatically detonate if anyone attempts to shut it off.
** In this case, the designers of the device [[JustifiedTrope built it like this intentionally]], and to them it made sense. It's meant as the ultimate, permanent deterrent to nuclear warfare; if there were any way to stop it once it's turned on, it wouldn't be able to carry out its function. It wouldn't have needed an off switch if not for a few miscommunications.
* Applies to the [[ColdWar U.S. and Soviet]] supercomputers in the film ''Film/ColossusTheForbinProject''.
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[[folder:Literature]]
* In RobertSheckley's short story ''The Laxian Key'', a pair of ne'er-do-wells find a machine that produces some substance in unlimited quantities but can only be turned off with the eponymous "Laxian key" (which they don't have). When the substance begins to flood their home (and they get a bill for the machine draining power from the city grid), they try to sell the machine to an alien race who feeds upon it, but are almost blown to pieces by the alien navy. [[spoiler:It turns out, these aliens, as a result of inventing the machine in the first place, already have several such devices... and, apparently, enough morons to turn them on. As a result, all of their homeworld is covered with it, so they tell the heroes to come back with the Laxian key and ask any price for it.]]
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[[folder:LiveActionTV]]
* Happens pretty much every week on ''{{Eureka}}''. A big piece of Tech is endangering the town, and Jack Carter asks something related to the easiest way to shut it off ("Why don't you just unplug it?"). Oh guess what, if you turn the device off, the town'll catch on fire, or something along those lines.
** This is a town where a boiler in the house is more likely to be a nuclear reactor, requiring a Ph.D. in Nuclear Physics to fix.
** In one case, Fargo accidentally activates a personal shield from a project that was specifically shelved because of this flaw. They only way to shut it off it to ''kill'' Fargo. Luckily, they do it in such a way as to quickly revive him after.
* On one episode of ''Series/BuffyTheVampireSlayer'', there was a lightning wielding gauntlet that could only be destroyed through a specific ritual.
* On the various ''Franchise/StarTrek'' incarnations, Holodecks have some kind of independent power source, so whenever they [[HolodeckMalfunction go haywire and stop responding to commands]], they usually can't simply pull the plug.
* Happens a couple of times on ''Series/{{Charmed}}'', such as when Billie put on [[ClingyMacGuffin Hippolya's]] [[ClingyCostume Belt]] and became a superheroine. The belt was killing her and the only way to remove it was through a specific spell found only in Magic School's library.
* In ''Series/StargateSG1'' and ''Series/StargateAtlantis'', the body-swapping device didn't have an off-switch (or at least it was never discovered) so every time someone activated it, he had to destroy it.
* Not having an off button is listed as a ''feature'' in the ''{{SNL}}'' parody commercial for the [[http://www.hulu.com/watch/70317 Woomba]], a robot for cleaning women's genitalia. The product is shown [[GoneHorriblyWrong Going Horribly Wrong]] during the actual commercial.
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[[folder:Music]]
* A certain BawdySong about a sex machine with a Bloody Great Wheel includes the ominous rhyme, "And now we come to the tragic bit, there was no way of stopping it".
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[[folder:Radio]]
* In ''Radio/TheHitchhikersGuideToTheGalaxy'' radio series, there's a malfunctioning clone machine which keeps starting new clones when the previous clone is only partly done. Its operators can't turn it off because if they did, they'd be liable for murdering the clones that are in mid-cloning when the button got pushed.
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[[folder:Real Life]]
* Certain devices that rely on chemical reactions obviously can't be easily shut down once the reaction starts, unless you have control over the access to the reactants themselves.
* Solid fuel rocket motors are perhaps one of the more consequential devices not to have an off button. Compare with liquid fueled rockets which can be both throttled and shut down by controlling the propellant flow, a solid fuel motor will burn at a predetermined rate until all the fuel is used up. In the case of the [[https://en.wikipedia.org/wiki/Space_Shuttle_Solid_Rocket_Booster Space Shuttle Solid Rocket Booster]] this severely limited the shuttle abort modes meaning the crew was basically stuck until the boosters had burnt out no matter what might start to go wrong.
** Doubly a problem when nuclear warheads are attached to solid fueled rockets, although a SelfDestructMechanism can be employed.

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[[folder:VideoGames]]
* In ''{{Zak McKracken and the Alien Mindbenders}}'', the titular Mindbender only have a big ON/ON switch; throwing it seemingly does something (reverses the polarity?), but turning it off is impossible. Given that it's designed to induce stupidity, this is a perfectly sensible design choice. Fortunately, [[spoiler:it can be destroyed by the Skolarian Device.]]
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[[folder:Western Animation]]
* In a mundane version, once on ''TheSimpsons'' when Homer decided to become an inventor:
-->'''Homer:''' Now, here's my "Everything's O.K." alarm!
-->''Homer flips a switch the device, and it begins to emit a high pitched, incredibly loud beep. The rest of the Simpsons cover their ears as Homer speaks up.''
-->'''Homer:''' This will sound every three seconds, unless something isn't okay!
-->'''Marge:''' Turn it off, Homer!
-->'''Homer:''' It can't be turned off! ''[alarm fizzles out]'' But it, uh, does break easily.
** Another ''Simpsons'' example; in the episode where a shady dealer sells Springfield a monorail, and it ends up going out of control, cutting the power is suggested, but the monorail is run completely on solar power... the monorail stops only when an eclipse happens... and then when the eclipse ends, the monorail keeps right on going.
* An episode of ''WesternAnimation/TazMania'' guest-starred Marvin the Martian who sets up a device to destroy the Earth rigging it, so once it's activated, even he can't shut it off. After turning it on, he realizes he's made a slight miscalculation:
-->'''Marvin:''' In 10 minutes it will all be over for you pitiful Earthlings. My ship will be here to pick me up in approximately one hour so.... Uh oh.
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