->''"Still, the power of the diary began to scare [Ginny], and she tried to dispose of it in the girls' bathroom. And then, who should find it but you, the very person I was most anxious to meet?"''
-->-- '''The memory of Tom Marvolo "[[TomTheDarkLord Lord Voldemort]]" Riddle''', ''Film/HarryPotterAndTheChamberOfSecrets''

Sometimes plans don't work out right the first time. That might [[NeverRecycleYourSchemes discourage you from trying again the same way]]. Or they don't do it again because [[NoPlansNoPrototypeNoBackup the plans were destroyed and can't be retrieved]].

But this time, the item still does exist. Maybe the creator thought it was a failed experiment the first time and wouldn't do anything if they left it lying around, or that it was [[ThingsManWasNotMeantToKnow too dangerous to ever use]]. Maybe it was a PointlessDoomsdayDevice left behind by NeglectfulPrecursors who didn't think about what would happen after they finished with it. Or it could have been an ArtifactOfDoom that was judged as more trouble than it was worth. Regardless of motives, rather than getting rid of the object because they don't need/want it anymore, the object remains, [[OutOfSightOutOfMind possibly left to gather dust in a warehouse or filing cabinet somewhere]]. It's also just as likely that the owner [[GrailInTheGarbage simply threw the device out and it was found later in the trash]]. And so long as it still exists, it can be retrieved or brought back to continue to cause more problems.

These plots could have been avoided had the item in question had been [[NoManShouldHaveThisPower properly destroyed in the first place]].

If the "device" is a previous version that had since been retired from use and put into storage, it may be a [[FlawedPrototype flawed]] or [[SuperPrototype super]] prototype.

Compare SealedEvilInACan. BreakOutTheMuseumPiece is this for when the device that would have otherwise been discarded suddenly became useful again; ArchaeologicalArmsRace for devices long forgotten. Also comparable with CardboardPrison regarding repeat offending criminals. A very good answer to repeated questions of WhatHappenedToTheMouse.

See also LostSuperweapon if the dangerous device is being sought but can't be found, and ForgottenSuperweapon, where the device is accessible but everyone conveniently forgets they possess it.

----
!!Examples:

[[foldercontrol]]

[[folder:Anime & Manga]]
* In ''Franchise/LyricalNanoha'' the Tome of the Night Sky is a weapon of mass destruction that teleports itself to safety whenever it is about to be destroyed. It'll then be discovered by a person with a linker core who will recharge it, not knowing just how dangerous it will become.
* In ''Manga/OnePiece'', the line of master shipwrights of Waters Seven have held onto the blueprints for [[WeaponOfMassDestruction Pluton]], despite hoping that it will never be used. Their reasoning is they need it [[GodzillaThreshold as a contingency]] in case someone got the designs from reading the Poneglyphs scattered around the world. [[spoiler:Franky only [[NoMacGuffinNoWinner destroyed the blueprints]] once he was convinced Robin (the only person known to be able to read Poneglyphs) wouldn't resurrect Pluton and that the Straw Hats could rescue her before the World Government could make her.]]
[[/folder]]

[[folder:Comic Books]]
* In an issue of ''ComicBook/TheIncredibleHulk'', a lower-level baddie working for a bigger bad (whom we never really see) discovers a cache of Hulk-busting equipment and decides to steal one and kill the Hulk with it. Turns out the reason it's all been stashed away is it doesn't work: the particular item she uses has a YourMindMakesItReal interface, and when the Hulk rips it to pieces it makes her feel like she's being ripped apart.
* ''ComicBook/TheSmurfs'': In the album ''[[Recap/TheSmurfsBook5Story1TheSmurfsAndTheHowlibird The Smurfs and the Howlibird]]'', Papa Smurf tests out a magic fertilizer on a daisy, but gets a [[ManEatingPlant Smurf-Eating Plant]] as a result. He tasks a couple of Smurfs to get rid of the dangerous compound in the desert. They, however, get tired and fed up by the long trek, and opt instead to throw the vial down a cliff. Unfortunately, after it breaks a droplet falls down the gullet of a hungry bird chick, which turns into the monstrous Howlibird as a result.
[[/folder]]

[[folder:Fan Works]]
* In ''Fanfic/TheWeaverOption'' the Book of Unblemished Ecstasy is a relic created by a proto-Slaaenshi cult before the fall of the Aeldari Empire. Lelith destroyed the cult but found the Book impossible to permanently destroy. In the past she has shredded the thing and thrown its remains into stars only for it to reappear intact elsewhere and start more trouble.
* The ''Fanfic/FacingTheFutureSeries'' story "Ancient History" showed that Danny returning the Scarab Scepter of King Duulaman to the museum at the end of canonical episode "King Tuck" wasn't a good idea [[spoiler:when Hotep-Ra and Tucker's separated ghost half steal it back to transform all of Amity Park. At the end of the story, it's rectified when Danny places it in the safety of Tucker's underground bunker]].
* This particular trope kicks off the events of ''Fanfic/TheRiseOfDarthVulcan'', because Twilight Sparkle decided to toss The Alicorn Amulet into a portal that wound up leading the artifact to land in the hands of [[TomTheDarkLord Ted]].
[[/folder]]

[[folder:Films -- Animation]]
* In ''WesternAnimation/WreckItRalph'', the terrible world-destroying devices are the Cy-Bugs, giant mechanical insects who consume and attack uncontrollably. These are regenerated and always recalled to be vaporized between Hero's Duty games so they don't cause any more trouble than they have to. When Ralph accidentally activates one and sends it flying into Sugar Rush, it sinks into liquid taffy and Ralph thinks that's the end of that; it's dead and not worth worrying about. However, he doesn't actually ''confirm'' that the bug is dead, and it spends the rest of the movie eating candy and laying eggs to produce more bugs leading to a massive SugarApocalypse.
* As shown in ''WesternAnimation/MyLittlePonyEquestriaGirlsForgottenFriendship'', when Clover the Clever buried the Memory Stone in the human world, he bundled instructions on how to use it, ensuring that anyone who happened upon it would know exactly what it was.
* Played with in ''WesternAnimation/StevenUniverseTheMovie'': Most of the plot is based on a weapon called a rejuvenator that gave Garnet, Amethyst, and Pearl IdentityAmnesia. Steven actually gets it away from the [[BigBad Spinel]] very quickly, and after learning what it is, tries to store it in [[PocketDimension Lion's mane]], where no one else can reach. However, the rejuvenator also severely weakened his powers to the point he can't do that, so Steven just sticks it in his jacket. [[spoiler:This ultimately backfires, but not because it gets used against Steven or his allies again. Steven convinces Spinel to undo her actions, but then she sees he still has the rejuvenerator on him and [[ImproperlyParanoid assumes he was going to use it again]] ''on her''.]]
[[/folder]]

[[folder:Films -- Live-Action]]
* In ''Film/SpyKids1'', the inventor of the Third Brain is told to destroy it. Thinking it is too valuable to destroy, he exchanges it with a walnut and breaks that instead. This allows Floop and Minion to create an army of artificially intelligent Spy Kids robots.
* Played with in ''Film/TransformersRevengeOfTheFallen''. After the events of the first film, the American government tries to dispose of Megatron's remains by dumping him at the bottom of the ocean, thinking that he'd be down so deep and under so much pressure that he couldn't possibly be retrieved. Cue team of Decepticons going deep-sea diving to get him.
* The Stronghold family in ''Film/SkyHigh2005'' defeated Royal Pain and took the weapon Royal Pain wielded, The Pacifier, as a new addition to their ever-growing [[SuperheroTrophyShelf collection of confiscated weapons they keep as trophies]] even though they don't know what it does. Years later, Royal Pain plots to retrieve the Pacifier by stealing it back from the Strongholds. Royal Pain [[spoiler:even uses their tendency to collect trophies by sending giant robot with a big shiny part for them to take. The "trophy" was a camera to allow Royal Pain access to the vault.]]
* Early in ''Film/TheAdventuresOfSharkBoyAndLavaGirl'', Mr. Electric disposes of the heroes by dumping them in the Dream Graveyard. However, his boss Minus chastises him for this because the heroes aren't crushed and they could find a potential ally there, and that's exactly what the heroes do. They find the remains of Tobor, the half-built TinCanRobot Max abandoned, asked him for advice, and used the moving parts on his face for transportation.
* ''Return To Film/{{Halloweentown}}'' centers around a magical artifact known as the Gift, which had the power to control and enslave all people. The Gift can only be borne by a Cromwell witch, but Splendora Cromwell could not destroy it herself; only the combined power of three Cromwells could do so, and so Splendora buried the Gift. 1000 years passed and those who want to use the Gift manipulate Marnie into being the new chosen bearer in order to rule Halloweentown, but with the help of her mother and brother she destroys it. Afterward, this trope is discussed, saying that there's no way Marnie would have destroyed the Gift but instead would secretly give it to someone responsible, someone she trusted to never use it's power unless they absolutely had to.[[spoiler: The last shot shows her brother Dylan discovering the Gift in a book he's reading, to his surprise]].
* One of the running subplots of ''Film/AvengersInfinityWar'' is the attempts by Scarlet Witch, Steve Rogers, et al to safely remove the Mind Stone from Vision so it can be destroyed and kept out of Thanos's hand. Through much of the movie Scarlet Witch has the opportunity (and permission from Vision) to destroy the stone with it still embedded inside him, likely killing him, but she can't bring herself to do that. In the climax, [[spoiler: she finally acquiesces, but it ends up being too little too late. She [[HopeSpot destroys him and the stone]], but Thanos, practically standing over her at the time, uses the Time Stone to revive Vision and the Mind Stone, and [[FamilyUnfriendlyDeath tears it out of Vision's head himself]], killing Vision and obtaining the 6th and last stone.]]
[[/folder]]

[[folder:Literature]]
* ''Franchise/StarWarsLegends'':
** In ''[[Literature/JediAcademyTrilogy Dark Apprentice]]'', the New Republic attempts to dispose of the Sun Crusher, a shuttle-sized supernova-causing weapon, by dropping it into a gas giant. [[spoiler: Shortly afterward, possessed Jedi hopeful Kyp Durron yanks it back out and uses it to blow up Admiral Daala's fleet and an Imperial solar system.]] And that's "dispose of", not "destroy", because it's literally MadeOfIndestructium; dropping it into a gas giant in the hope of keeping it from falling into the wrong hands--not that there are ''right'' hands for that kind of weapon--was something of a desperation tactic.[[note]]Though it's implied the New Republic government chose a gas giant rather than [[HurlItIntoTheSun a star]] in hopes that ''they'' might be able to recover it if needed.[[/note]] [[spoiler: Once it's recaptured, Luke ends up launching it past the event horizon of a handy black hole. That seems to have done the trick.]]
** The ninth ''Literature/GalaxyOfFear'' book, ''Spore''. The Ithorians are a race of plant-loving people who regularly indulge in gene splicing to make new and better species. They decided to splice the sentient, Force-sensitive Bafforr tree with a hostile ensnaring tree, and created Spore. The result? Spore became a sentient, ensnaring hive-mind that attempted to take over as many people as possible and it took centuries before the Jedi could finish it off. However, the Ithorians [[ThouShaltNotKill are a peaceful people who won't destroy anything]], including their most hostile creation, and instead sealed it inside an asteroid within the vacuum of space. Space miners [[DugTooDeep open up Spore's chamber and release it again]], and as it spreads it draws the attention of [[VideoGame/DarkForcesSaga Jerec]], who intends to give Spore as many bodies as it wants in exchange for allegiance with Jerec.
* In the BackStory to ''Literature/TheLordOfTheRings'', the Last Alliance of Elves and Men conquered Mordor, at the cost of tons of lives. Isildur cut off Sauron's finger and obtained the One Ring. Instead of throwing it into Mount Doom which was ''right there'', and destroying it the way Elrond suggested, he decided to keep it. This allowed Sauron to rebuild Mordor, which led to the War of the Ring.
* From the ''Literature/{{Discworld}}'', the "gonne" is a six-shot repeating rifle invented by [[MadScientist eccentric genius]] Leonard of Quirm. Lord Vetinari recognized the danger of the device and handed it over to the Assassins' Guild to be destroyed, on the basis that they'd be the ones who'd be most strongly opposed to what it represented (cheap, efficient killing from a safe distance, as opposed to up-close, personal and ''highly-paid'' assassination). However, instead of ''destroying'' it as ordered, they decided to lock it away in a secret museum as a warning... where a renegade assassin was able to steal it, kicking off the plot of ''Literature/MenAtArms''.
* ''Literature/HarryPotter'':
** ''Literature/HarryPotterAndTheChamberOfSecrets'': As soon as Ginny realizes that the special diary she's been writing in for the whole book has been controlling her and causing her to do some terrible things, she tries to get rid of it by flushing it down the toilet. Harry and Ron find it shortly afterward and bring it back to to the Gryffindor room, which once again delivers the book straight to Ginny's hands. Harry later destroys it properly by stabbing it with a poisonous basilisk fang so it could never harm anyone again.
** Voldemort invokes this trope by using multiple backup horcruxes, including the diary mentioned above, so that if one gets destroyed, he'll have backups. Horcruxes by themselves are pretty difficult to destroy. When Regulus Black tracks one down and orders Kreacher to destroy it, Kreacher makes multiple attempts but fails to even dent the thing. ''Literature/HarryPotterAndTheDeathlyHallows'' is one long FetchQuest of lost, cursed items that have to be retrieved and systematically destroyed.
** Dumbledore is not immune either: he tries to depower the Elder Wand, sought by Voldemort, [[spoiler: with the help of Snape: being killed by consent doesn't mean being defeated, so the Wand should die with him. Unfortunately, it doesn't work, and other than that there's no obstacles for Voldemort to retrieve it from his grave. When Voldemort is killed for good, Harry returns it to Dumbledore's grave, hoping that too few people know about its importance, effectively leading to almost the same problem. Latter part is averted in the film: Harry simply snaps it in two and throws pieces into ravine.]]
* In the comic-within-a-comic of ''Literature/CaptainUnderpants'', ''Hairy Potty and the Underwear of Justice'', a scientist who finds his hair growing potion has the side effect of making the user turn giant and evil tries to get rid of it by pouring it down the toilet. But he forgot to flush, and thus the toilet turned giant, hairy, and ''evil''.
* This trope sets off the plot of the fourth ''Literature/CircleOfMagic'' book. [[spoiler: An IneptMage who was experimenting with a weight-loss potion that wasn't working out decided that rather than pay the fees to have her failed potions safely destroyed (as the law required), she would simply dump them in the sewer. The magic in her potions reacted with the existing filth in the sewers to create an incredibly dangerous disease that killed thousands before a cure was discovered.]]
* This sets up the climax of ''Literature/TheLastDaysOfKrypton''. As part of his rise to power, General Zod uses the Phantom Zone Projector to imprison most of Krypton's nobles. After they are rescued, the Nobles want the Projector to be destroyed. Jor-El, the inventor of the device, points out that it's actually a contained singularity, and therefore ''cannot'' be destroyed. Being the former TropeNamer for IgnoredExpert, the Nobles dismiss his concerns and set about to try. [[spoiler: They decide to throw the Projector into Krypton's core, figuring the heat and pressure will do the job. Instead, the Phantom Zone ''devours'' the planet's core, bringing about the world's destruction in a matter of days.]]
[[/folder]]

[[folder:Live-Action TV]]
* The scientists at Global Dynamics on ''Series/{{Eureka}}'' are pretty bad about how they dispose of dangerous failed prototypes. 2 episodes revolve around the consequences:
** ''Try Try Again'' shows that GD has a "vault" where abandoned projects are stored, with little more than a single underpaid clerk keeping track of everything. [[spoiler: He's so underpaid that he regularly steals things to take apart and sell the pieces.]] Nobody seems to know what any of the stuff is or why it was shelved without access to the computer mainframe, and there's no care taken to ensure the shelved prototypes have their power sources removed and/or that neighboring devices don't affect each other. Included in the vault was a personal forcefield device that creates an ever expanding forcefield that pushes all matter in its way out of its way. Oh, and its backup power source is to suck the life out of the person it's meant to protect.
** ''Phased and Confused'' reveals that failed prototypes are also "recycled", but do the scientists themselves dismantle their creations? Nope, just send them off intact and "functional" to the local recycling yard and let them take care of it. [[spoiler: Cue recycling guru, Chuck, keeping many of the prototypes for himself in order to fulfill his delusions of becoming a superhero. Including a phase shifting devices that lets its wearer walk through walls, which was decommissioned because it caused its users to spontaneously fall apart at the molecular level.]]
* ''Series/Warehouse13'' is a giant case of these waiting to happen, as the titular warehouse contains countless thousands of supernatural artifacts with powers ranging from amusing to apocalyptic, with more being created in the world all the time. And yet the people who work there are all a bit wacky and can hardy go three episodes without an outsider finding out the secret.
** Not all things hidden in the Warehouse are dangerous or supernatural. For example, the Farnsworth is a practical VideoPhone built by the inventor of the TV that works anywhere on earth and is completely untraceable. There's also an electric car that is powered by human bioelectricity. There's no good reason why that stuff isn't available to the general population.
** The general excuse is that even the amusing ones have a DarkAndTroubledPast that lead them to warehouse custody, the seemingly beneficial ones have negative side effects and some unspecified consequence in destroying multiple artifacts in short order. Potentially the truly positive ones can be given but that opens the potential for unscrupulous seekers of the more dangerous ones, which various big bads have done with global implications.
** There's an episode where an outsider learns about the warehouse, and The Regents decide that the best course to prevent her from going public is to have Pete give her a tour. She still wants to go public until Pete gives her a big speech about how even the beneficial/benign ones still need to be protected, because "how can you tell the world about some of this without letting the rest out too?"
* On the old ''Series/KnightRider'' show, the prototype of the indestructible supercar, complete with sociopathic faux-military programming, is contained by... turning it off. With a big wall switch that any random burglar could mistake for a way to turn on the lights. In a warehouse that's sold, only a year or so later, without anybody bothering to clear the place of dangerous or valuable items. "Hey, boss, didn't we park a murderous thousand-horsepower armor-plated billion-dollar robot Pontiac here last year?" "Ain't on the work order, Joe, just turn out the lights and clock out."
* ''Series/SabrinaTheTeenageWitch'' writes a cheesy spy story, [[WriteWhoYouKnow makes her friends Valerie and Harvey the heroes]], her teacher Mrs. Quick becomes a GadgeteerGenius, and Vice Principal Kraft becomes an evil Bond villain who gives out exploding detention slips. In a twist, the characters magically come to life and start acting out the story just as Sabrina wrote it, and Sabrina didn't know that the typewriter she was using was magical. Hilda admits the reason she didn't throw out the magical typewriter like Zelda ordered her to was because she loved to write romances with herself as the heroine and watch them come true.
* ''Series/DoctorWho''. In "[[Recap/DoctorWhoS14E2TheHandOfFear The Hand of Fear]]" the dangerous object is Eldrad, a convicted criminal from a race of SiliconBasedLife who are very hard to kill. He's sent off in an automated spacecraft which is meant to be detonated in deep space, but the apocalypse Eldrad caused to happen means the authorities can't wait that long, so they blow up the ship too early and his [[HelpingHands creeping hand]] survives and eventually lands on Earth, whereupon he is [[SealedEvilInACan able to regenerate]].
* In ''Series/AgentsOfShield'', the "Slingshot program" is designed to get rid of technology or objects deemed too dangerous for ''anyone'' to possess, by loading them into a rocket and shooting them into the sun. [[spoiler: Except that the entire project is a fake, meant to make it LOOK like the devices were destroyed, while they're actually stored in a SHIELD facility for later study or possible use. This turns out poorly when Hydra raids the place and takes their pick.]]
* ''Series/MakoMermaidsAnH2OAdventure'': The [[ProngsOfPoseidon trident]] was an anti-mermaid weapon sealed away by the merman king after he betrayed his pod. While the security on the seal was difficult to get through when he created it [[note]](the Trident Chamber only appears for a few minutes at midnight during a full moon on a remote island guarded by hostile mermaids, and the interloper has little time to swim through an endless underwater room before they can reach the trident lest they get trapped until the next full moon, nevermind the portal that will drop them into the Moon Pool where more angry mermaids will be waiting)[[/note]], technology has since advanced to the point where a man with scuba gear could surmount all the obstacles. The mermaids have the excuse that the trident will kill them if they try to interact with it, but Zac was able to break the trident by telekinetically smashing it against a wall, raising the question of why the merman king didn't do the same.
[[/folder]]

[[folder:Video Games]]
* ''Franchise/TheLegendOfZelda'':
** In ''VideoGame/TheLegendOfZeldaMajorasMask'': The eponymous mask was previously used by a tribe in dark rituals before they realized how terrible its power was and sealed it in shadow. By the time the game begins, the Happy Mask Salesman is carrying it around as part of his collection like it's nothing, giving the Skull Kid a perfect opportunity to mug the Mask Salesman and take the mask from him.
** In ''VideoGame/TheLegendOfZeldaTwilightPrincess'': This actually works in the good guys' favor. While Zant used the Mirror of Twilight to enter Hyrule from the Twilight Realm, he tried to break the mirror so Midna and Link couldn't enter the Twilight Realm. However, Midna says only the true ruler of the Twili could break the mirror properly and that Zant is a fake, so she and Link go on a quest to retrieve the mirror shards and put the mirror back together. [[spoiler:After the game ends, Midna properly destroys the mirror, ensuring it would never be used again.]] The same applies to the Fused Shadows in the context of the Hyrulians, but for Link and Midna it's more like BreakOutTheMuseumPiece. [[spoiler:This doesn't stop Ganondorf from crumbling them to pieces by the end]].
* This is the background of the Hammer Station flashpoint in ''VideoGame/StarWarsTheOldRepublic''. A mobile battlestation designed to hurl asteroids at planets was ''supposed'' to be autopiloted into a sun, but the autopilot failed and the thing ended up in the hands of a faction of aggressive expansionists.
* At the end of ''VideoGame/FinalFantasyXIV'''s patch 3.3 story quests, Alphinaud and the [[PlayerCharacter Warrior of Light]] toss [[spoiler:Nidhogg's eyes]] into the nearby abyss -- which predictably end up in the hands of the Ascians by their next appearance. [[AuthorsSavingThrow It wasn't explained until 3.5]] that they were ''expecting'' them to be destroyed in a torrent of eternally clashing wind and water aether that resides at the bottom of the abyss in question. [[spoiler:{{Defied|Trope}} much later, the next time Team Good gets their hands on the things -- Estinien notes that they're completely depleted of aether anyway, but takes no chances and destroys them for good on the spot.]]
[[/folder]]

[[folder:Web Original]]
* ''Website/SCPFoundation'':
** Not all of the instances are "devices", but this is more or less the entire point of the ''Website/SCPFoundation''. Special mention goes to [[http://scp-wiki.wikidot.com/fragment:scp-3145-3-682 SCP-3145 (SCP-682), the "hard-to-destroy reptile"]], which the Foundation has attempted to dispose of [[RunningGag again and again]], [[FailureIsTheOnlyOption always without success]].
** Played more straight with the Foundation's sister organization, the GOC Coalition, which is more about ''destroying'' anomalies, as opposed to the Foundation's operating procedure of ''containing'' them, save for a few exceptions such as the aformentioned 3145 (682). The latter justifies this by noting that more times than not, attempting to destroy an anomaly has the risk of backfiring (it ends up being something needed to handle a worse threat, it comes back as something worse, etc.). Special mention goes to [[http://www.scpwiki.com/scp-1609 SCP-1609]]; originally a comfy chair that would appear near someone in need of a relaxing sit-down, GOC agents' attempt to destroy it by putting it through a shredder only turned it into a temperamental pile of nail-ridden mulch that does. not. LIKE. GOC, weapons, or uniforms. (The agents were supposed to incinerate it, but there's no guarantee the result wouldn't be annoyed ash.)
[[/folder]]

[[folder:Western Animation]]
* Uncle Chuck of ''WesternAnimation/SonicTheHedgehogSatAM'' created the robotocizer for the purpose of healing serious war injuries by converting their flesh into cybernetics, but discarded the invention after it turned out it also robbed people of their free will in the process. Leaving the blueprints unattended was the pivot in Julian Robotnik's conquest of the entire planet of Mobius.
* One episode of ''WesternAnimation/TheAdventuresOfJimmyNeutronBoyGenius'' had Jimmy attempt to create a device to bring his friend Carl's dead goldfish back to life, but it didn't appear to work at first. Jimmy resolves to just dump the invention in the failed experiments file, but Carl asks if he can keep it as a memento of his dead fish. Jimmy lets him, seeing as that it doesn't work anyway. However, the fish is shown coming back to life after they leave. Later on Carl offers to [[MundaneUtility use it to generate a spark to relight a torch]] while exploring a pitch-black tomb in Egypt, only for the mummies buried there to come back to life.
* ''WesternAnimation/DannyPhantom'' is occasionally savvy about this.
** The first time he dealt with [[IneffectualSympatheticVillain Sidney Poindexter]], he ensures to smash his mirror portal so he can't return (he inexplicably does in "Reign Storm", but he's barely a villain by then).
** When Danny has the [[RealityWarper Reality Gauntlet]] in his possession, he makes certain to blast it to pieces so it can't be used again.
** Played straighter in "Secret Weapons", where Vlad reveals he recovered the [[DeadlyUpgrade Fenton Battlesuit]], upgraded it and forced Jasmine to wear it.
* ''WesternAnimation/TransformersRescueBots'':
** Underneath Griffin Rock in ''WesternAnimation/TransformersRescueBots'' lies a whole warehouse full of old inventions, including a large section known as the "Best Left Forgotten" shelf. Items left behind on that shelf managed to cause the plots of several episodes.
** A later episode revealed the presence of the Island of Misfit Tech, where devices too dangerous for the BLF shelf are teleported to. This trope comes into play in that a) the devices are never powered down, as Cody learns when he's accidently teleported there, and b) they're also fitted with a special retrieval device, ostensibly in case someone wants try their hand at repurposing them.
* ''WesternAnimation/MyLifeAsATeenageRobot'':
** Before Jenny was built, Nora Wakeman invented a giant sentient robot named Armagedroid to defend Earth from aliens by absconding with and promptly destroying all alien weaponry. It worked, but [[GoneHorriblyRight too well]] as Armagedroid started destroying absolutely anything that could be possibly be conceived as a weapon until Wakemen tricked him into going to the Earth's core. He comes back and terrorizes Jenny, being a ''sentient weapons system''. Nora then charges Jenny with the task of getting rid of him by blowing him to pieces. Armageddroid still manages to reappear in a later episode anyway--[[UnexplainedRecovery somehow]] ''[[BoisterousWeakling Killgore]]'' rebuilt him, all on his own.
** This happens on a regular basis to Jenny. One episode, she disposes of a muck monster by running it into a gelatin plant, and acts surprised when it returns as a gelatin monster in the school cafeteria at the end of the episode.
** Right at the beginning of "Escape From Cluster Prime," Jenny recklessly stops a flying rocket, but is quickly reminded by Nora that she should have disarmed the warhead as well. Obviously, it explodes.
* ''WesternAnimation/TheBatman'': In the episode “Brawn”, Joker was able to get a hold of Bane's Venom module because it was in Gotham [=PD=]'s evidence lockup.
* In the ''WesternAnimation/TeenTitans2003'' episode "X", it's discovered that an unknown individual had stolen the original Red X costume from Robin and has been using it for thieving. Discussed when Beast Boy suggests that he must be kicking himself that he never got rid of the suit before it was stolen, and Justified as Robin explains that the suit couldn't be destroyed; its Zynothium power source made it too dangerous to be disposed of safely.
* ''WesternAnimation/LiloAndStitchTheSeries'' used this as its premise. The pilot movie, ''WesternAnimation/StitchTheMovie'', showed that Jumba kept all his illegal genetic experiments dehydrated into pods and carefully locked in a single storage unit. By the end, the thing breaks and all the little pods rain all over the island, coming into contact with water and wreaking havoc everywhere. The series centers around Lilo and Stitch tracking down every experiment and finding the places each one belonged.
* In ''WesternAnimation/GravityFalls'', rather than destroy the journals he had written containing the secrets he had learned, [[spoiler:including the schematics for his [[NoManShouldHaveThisPower Universal Portal]]]], the Author buried each one in a different location. [[{{Pride}} The Author simply couldn't stand the idea of his research being destroyed]], regardless of the danger they posed, and ''flipped'' when a colleague [[CuttingTheKnot tried to burn one of them instead]].
* Justified in ''WesternAnimation/MyLittlePonyFriendshipIsMagic'', where it was stated that the Bewitching Bell of Grogar [[MadeOfIndestructium couldn't be destroyed]], so Gusty the Great was forced to instead seal it away in a cave atop of a mystically windy mountain. [[spoiler:Fortunately, despite being indestructible, it was rendered inert and useless by an extremely powerful blast of friendship rainbow]].
* In the backstory of ''WesternAnimation/YoungJustice2010'', the Justice League first cane together to fight the Appellaxians, energy beings who fought using special host bodies made of different materials. After driving off the Appellaxians, the Justice League took the four remaining husks (made of gold, rock, crystal, and wood respectively) and kept them as trophies. Years later in the second season, the criminal organization Intergang used Apocolis Tech to combine the husks into a singular golem following their whim. [[spoiler:In the end, it gets destroyed by an ally of the Light to keep it from joining up with the heroes that were reaching out to it]].
[[/folder]]

[[folder:Real Life]]
* Scientific protocols often require that certain materials be discarded in hazardous waste bins for proper disposal with potential fines imposed if they don't. Especially for those who work with chemicals or live cultures.
* Paper with sensitive information is usually discarded by passing it through a shredder. Really sensitive papers would also be bleached and rendered down to pulp. Not destroying these can result in identity theft.
* If the sensitive information is on electronic media, ordinary file erasure is unsafe; there are ways to recover and read the data. The files need to be subjected to special multiple-erasure processes, or (to be really sure) the media should be physically destroyed.
* For a while at least, the official NATO method for destroying low-level classified data on [=CD=]s was to microwave them. If you have a few [=CD=]s or [=DVD=]s you don't need, throw one in the microwave for 4 seconds. Quite entertaining.
* [[https://en.wikipedia.org/wiki/Goiânia_accident The Goiânia accident:]] In 1987, a radiation therapy clinic in Brazil had relocated to a new office and had left behind one of their teletherapy machines — they've got into a legal dispute with a building's owners and received a court injunction forbidding them to take it to their new premises. The building was later partially demolished, but the machine was still intact in a remaining wing. Years later, two scavengers broke into the site looking for scrap metal to sell. They found the machine and broke it open, releasing the highly radioactive Cesium-137 from its lead container. The scrapyard owner who received the capsule from them mistook the glowing blue powder for carnival glitter; allowing children to play with it and spreading it around their homes and farms for good luck. The symptoms of radiation sickness were misdiagnosed as food poisoning. In total, 249 people were contaminated, with 129 suffering internal contamination from ingesting radioactive material. Four people died from whole body irradiation.
* Back in the 1970s there was a global campaign to wipe out smallpox, which thankfully succeeded. However, small scientific samples of smallpox still exist in various bio-hazard containment caches. In 2014, forgotten vials of smallpox were discovered while clearing out a storage room in the National Institutes of Health in Bethesda, Maryland. It's unknown if other samples still exist.
* Product recalls often result in a few examples escaping the recall, especially if it's a voluntary recall. For example, the Samsung Galaxy Note 7 recall was voluntary, and so far figures show 60% of devices have been returned. That means that there are quite a large number of potentially very dangerous phablets still to be returned...
[[/folder]]
----