History Main / LeakingCanOFEvil

* ''ComicBook/AntMan2022'': After Ultron's defeat over in the pages of ''Iron Man'', the Avengers seal him up in a vibranium casket covered in Asgardian runes, hoping that ''this time'' it'll keep him locked up forever. [[spoiler:Turns out he was still able to call out to Black Ant, persuading him to come and free him. And that the Asgardian magic had interacted with Ultron to give him a power boost.]]
* This is how Winnowill from ''Comicbook/{{ElfQuest}}'' ends up when Rayek traps Winnowill's soul inside his own. Winnowill is mostly contained but occasionally is able to either affect Rayek's actions or even lash out with her own magic powers. She even manages to [[spoiler:start a cult, with herself as the "Redeemer", at one point, due to]] leaving signs lying around. Learning about them is what causes Rayek to realize she is leaking.
* ''ComicBook/{{Shadowpact}}'' reveals that the slumbering, highly powerful and ''very'' EvilSorcerer Dr. Gotham has been sleeping beneath (wait for it) [[Franchise/{{Batman}} Gotham City]] for centuries. He inadvertently influenced the city into becoming a crime ridden cesspool with a penchant for attracting costumed lunatics.
* In ''Comicbook/BillyBatsonAndTheMagicOfShazam,'' [[KidHero Billy]] turns out to have accidentally made himself a [[SealedInsideAPersonShapedCan Person-Shaped Can]] for [[spoiler:[[PsychicPowers Mr. Mind]]]], which after a few weeks causes first [[SuperPoweredEvilSide Captain Marvel]], then Billy to become NotHimself.
* ''Franchise/GreenLantern'': It's revealed in ''ComicBook/GreenLanternRebirth'' that Parallax, the yellow Fear Entity, was trapped inside the Central Battery a very long time ago, but his corruptible influence gave Green Lantern rings' weakness to yellow and briefly drove Hal Jordan mad.
* In the ''ComicBook/{{Hellboy}}'' comics, the Ogdru Jahad are imprisoned inside 7 giant magic cocoons; however, they can still communicate with certain humans. During the events of ''Seed of Destruction'', Rasputin was able to damage their prison and allow some of their power to leak into the world, which is implied to be the cause of practically everything bad that happens in the ''Hellboy'' and ''B.P.R.D'' comics afterwards (although the only confirmed consequence was [[spoiler:Nimue's transformation into their avatar]] during ''The Storm and the Fury'').
* In the Marvel Universe, cultists in the Eastern European country of Transia tried to summon a prehistoric EldritchAbomination named Chthon at the foot of a local mountain named Wundagore. Realizing their mistake, they sealed the part of it they managed to summon away in the mountain, but its presence is the reason why clay from the mountain can be sculpted into statues that can mind control others and why Wanda Maximoff has so much magical potential.
* [[EldritchAbomination The Umbrum]] in ''ComicBook/MyLittlePonyFriendshipIsMagic'' once roamed free and wrought havoc in the Frozen North (where Crystal Empire was later built), but were sealed away in another dimension thanks to the power of Crystal Heart. Although it still keeps them trapped in there, they are apparently still capable of influencing the real world to a degree, since they were able to disguise one of their own as a pony, send him to the Crystal Empire as both figurative and literal Trojan Horse and later communicate with him and awaken his latent powers.
* In ''ComicBook/{{Nova}}'', the Luminals imprisoned their archenemy Abyss in a high-tech coffin meant to suppress his powers while they prepared to get rid of him at the edge of the universe. Abyss managed to open a small crack in the coffin, however, and promptly started [[ZombifyTheLiving zombifying people]] in an attempt to free himself.
* ''ComicBook/Sabretooth2022'' sees the titular villain imprisoned forever in the Pit, below the living island of Krakoa. It doesn’t take long until his mind starts to haunt the island in various ways, though.
* A rather infamous issue of ''ComicBook/XMen'' revealed that Nightcrawler is actually the son of a demon, Azazel, who was locked in another dimension but is able to get free in order to father children [[ItMakesJustAsMuchSenseInContext with the goal of them being able to free him]] (though [[DependingOnTheWriter some issues]] state he needs those children to teleport his ''army'' out of the dimension).

* ''WesternAnimation/TeenTitans'': In "[[Recap/TeenTitansS3E6Spellbound Spellbound]]", Malchior is imprisoned in a TomeOfEldritchLore, but it doesn't prevent him from communicating with Raven and manipulating her into freeing him.

[[folder:Film — Live-Action]]

* In ''Manga/DeadmanWonderland'' [[spoiler: the eponymous setting is ''supposed'' to keep the Wretched Egg sealed with the help of the Mother Goose System, but you wouldn't know that based on how she gets to leave the Wonderland to massacre a middle-school class, cause earthquakes and generally wreak havoc such that everyone is forced to evacuate the island (save for the insane scientist who created her). And then we find out all her abilities displayed are not even 15% of her true power]].

* The [[GodOfEvil Kishin]] [[BigBad Asura]] from ''Manga/SoulEater'' was sealed in a bag made of his own skin. Even after this, his [[TheCorruption madness]] is strong enough to warp the statue of a god holding his container and make everyone who tries to approach it [[ThroughTheEyesOfMadness see horrible hallucinations]]. However, it is only when Asura is freed that his madness is able to spread all over the world.

* In ''Literature/KyoKaraMaoh'', the [[SealedEvilInASixPack Forbidden Boxes]] become this when brought together, due to the seals weakening over time, especially time spent in human lands outside the influence of the Demon Kingdom's magic. This prompts the protagonists to attempt a renewal of the seals, which winds up releasing the evil entirely.
* In ''Manga/DeadmanWonderland'' [[spoiler: the eponymous setting is ''supposed'' to keep the Wretched Egg sealed with the help of the Mother Goose System, but you wouldn't know that based on how she gets to leave the Wonderland to massacre a middle-school class, cause earthquakes and generally wreak havoc such that everyone is forced to evacuate the island (save for the insane scientist who created her). And then we find out all her abilities displayed are not even 15% of her true power.]]
* In ''Anime/YuGiOh'', the power of the Millenium Items is supposedly confined to the items themselves until invoked (willingly or not) by a user. However, for the Millenium Puzzle and the Millenium Ring in particular, the spirits within appear able to used their shadow powers to a limited degree anyway, even without a host.

A subtrope of SealedEvilInACan. If the evil is SealedInAPersonShapedCan, it will usually become this trope. If the evil is sealed within a physical object, that object is likely to become an ArtifactOfDoom. Compare MightAsWellNotBeInPrisonAtAll, for when this applies to mundane criminals. See also EvilIsNotAToy, EvilTaintedThePlace, SealedEvilInAnotherWorld, VillainousLegacy, and ResidualEvilEntity.

* ''Film/{{Mirrors}}'': Although the MirrorMonster is confined to the [[AnotherDimension mirror world]], it can influence the real world in malevolent and deadly ways from there. Also, though it seems to mainly reside in the abandoned Mayflower building, when it's stalking someone, it can appear in mirrors wherever they are.

* ''VideoGame/{{Diablo}}'': Due to the work of the [[BigGood Archangel Tyrael]] and a group of humans he trained named the Horadrim, the three Prime Evils, Diablo, Mephisto and Baal, were locked away into [[SoulJar soulstones]] designed to contain their essences and stop them from pursuing the Eternal Conflict onto Sanctuary. Unfortunately, these soulstones don't prevent the Evils from corrupting mortals who have the misfortune to be near their resting places, and all of them end up manipulating said mortals into releasing them, as a result of [[spoiler:[[FallenAngel Izual]]]] filling the Prime Evils in on how to corrupt them. Mephisto's soulstone in particular resulted in the Zakarum high priesthood becoming corrupted and turning into demons. In ''Diablo III'', all of the Great Evils, both the Prime and the Lesser Evils, get locked into the Black Soulstone, a super-jar for demons. Despite this, their power is such that spells must constantly be cast to prevent their demonic rage from leaking out.

* The primary antagonistic force in ''VideoGame/PokemonSwordAndShield'' is this. [[spoiler:Eternatus is a DraconicAbomination who arrived in Galar several thousand years prior to the game's start, wreaked havoc and was eventually sealed after a grueling battle from which even the mascot legendaries, Zacian and Zamazenta, walked out from with significant injuries. However, Eternatus' power continuously leaks out during those thousands of years, causing the Dynamax phenomenon where Pokémon randomly grow gigantic and rampage.]]

* In the Marvel Universe, cultists in the Eastern European country of Transia tried to summon a prehistoric EldritchAbomination named Chthon at the foot of a local mountain named Wundagore. Realizing their mistake, they sealed the part of it they managed to summon away in the mountain, but it's presence is the reason why clay from the mountain can be sculpted into statues that can mind control others and why Wanda Maximoff has so much magical potential.

* In the ''Hellboy'' comics, the Ogdru Jahad are imprisoned inside 7 giant magic cocoons; however, they can still communicate with certain humans. During the events of ''Seed of Destruction'', Rasputin was able to damage their prison and allow some of their power to leak into the world, which is implied to be the cause of practically everything bad that happens in the ''Hellboy'' and ''B.P.R.D'' comics afterwards (although the only confirmed consequence was [[spoiler:Nimue's transformation into their avatar]] during ''The Storm and the Fury'').

** Calamity Ganon from ''VideoGame/TheLegendOfZeldaBreathOfTheWild'' was locked up in Hyrule Castle for one hundred years. By the time the game proper begins, Ganon has reclaimed enough power to manifest itself as a mass of fog-like corruption surrounding the castle and resurrect monsters during a [[BadMoonRising Blood Moon]]. Worse yet, there's a very real possibility that Ganon will soon break out of its can and destroy what's left of Hyrule unless Link can put it down for good. At one point, Zelda theorizes that increasing numbers of monsters appearing around Hyrule are a sign that the seal placed over Ganon 10,000 years prior is failing and Ganon's return is imminent. [[spoiler:She's right. A few weeks/months later, Ganon does indeed break free, an event which culminates in the 100-year sealing of the game proper.]]

A subtrope of SealedEvilInACan. If the evil is SealedInAPersonShapedCan, it will usually become this trope. If the evil is sealed within a physical object, that object is likely to become an ArtifactOfDoom. Compare MightAsWellNotBeInPrisonAtAll, for when this applies to mundane criminals. See also EvilIsNotAToy, EvilTaintedThePlace, SealedEvilInAnotherWorld, VillainousLegacy, and ResidualEvilEnergy.

A subtrope of SealedEvilInACan. If the evil is SealedInAPersonShapedCan, it will usually become this trope. If the evil is sealed within a physical object, that object is likely to become an ArtifactOfDoom. Compare MightAsWellNotBeInPrisonAtAll, for when this applies to mundane criminals. See also EvilIsNotAToy, EvilTaintedThePlace, SealedEvilInAnotherWorld, and VillainousLegacy.

A subtrope of SealedEvilInACan. If the evil is SealedInAPersonShapedCan, it will usually become this trope. If the evil is sealed within a physical object, that object is likely to become an ArtifactOfDoom. Compare MightAsWellNotBeInPrisonAtAll, for when this applies to mundane criminals. See also EvilIsNotAToy, EvilTaintedThePlace, and VillainousLegacy.

* In ''LightNovel/KyoKaraMaoh'', the [[SealedEvilInASixPack Forbidden Boxes]] become this when brought together, due to the seals weakening over time, especially time spent in human lands outside the influence of the Demon Kingdom's magic. This prompts the protagonists to attempt a renewal of the seals, which winds up releasing the evil entirely.

** Shendu the demon sorcerer was sealed into the form of a statue when the magical talismans that control his power were removed from his body. When in this form he retains the ability to speak and apparently to breathe fire, which he uses as "persuasion" for the Dark Hand syndicate to retrieve the talismans and revive him.

* Double Subverted in [[https://www.fanfiction.net/s/6263444/1/Transition Transition]]:
** Unknown to the people who did the sealing Jinx had pulled a HeelFaceTurn by the time they did.
** The "leaking evil" part is caused by the can itself not working like the creators intended rather than the contents themselves.

* ''TabletopGame/CallOfCthulhu''. In his tomb on the sunken isle of R'lyeh dead Cthulhu lies dreaming. True to [[Franchise/CthulhuMythos the source material]] Cthulhu is capable of communicating with his followers through their dreams. In the ''Cthulhu Now'' supplement adventure "Dreams Dark and Deadly", Cthulhu was able to contact the minds of dreaming people and tried to use their magic points to create an avatar of himself that didn't need [[WhenThePlanetsAlign the stars to be right]] to exist.

*** The prisons of the [[DemonLordsAndArchDevils Overlords]] are pretty sturdy, with most of the Overlords having no power to affect the world at all (though they do have cultists/minions willing to work on their behalf). A few are able to affect the world ''very'' subtly, mostly by manipulating people, most notably Bel Shalor, the Shadow in the Flame.

** Ganon in ''VideoGame/HyruleWarriors''. After having his souls broken into four pieces and sealed away in the depths of space and time, he still had enough power to corrupt the sorceress Cia to recover the pieces, allowing for his resurrection.

* In ''VideoGame/HollowKnight'', the Black Egg temple contains ''something'' that's causing the Infection plaguing Hallownest, sealed by the three Dreamers, but the amount of Infection you encounter outside the temple, especially in the second half of the game, makes it clear that whatever it is, it's not completely locked down. [[spoiler: This thing turns out to be the titular Hollow Knight, a LaserGuidedTykeBomb meant to contain the source of the infection- The Radiance- in itself, but sealed in the Black Egg Temple when it proved unable to fully contain the plague, making this a double example.]]