Sealed Inside a Person-Shaped Can

So there is some Cosmic Being locked away so that it cannot interfere with the outside world. Some sort of powerful being... Good, Evil, or neither, it doesn't matter. But this time, they didn't lock away the being in a magical jar of some sort. Rather, they somehow managed to bind the thing into the body of a person. A person who may, or may not be aware that they are carrying around some Eldritch God within them.

Unleashing the Cosmic Being usually results in the "can" either dying or being subsumed into it (and occasionally, killing the "can" results in the destruction of the being). Occasionally causes a Battle in the Center of the Mind. Occasionally results in a Super-Powered Evil Side, for the evil, neutral and Knight Templar examples. Reincarnation may be involved. Occasionally overlaps with MacGuffin Girl.

A Subtrope of Sealed Evil in a Can, Sealed Good in a Can, and Sealed Badass in a Can. Contrast Grand Theft Me. Compare Treasure Chest Cavity.

Anime And Manga

 * Naruto: The Jinchuriki are a people who have tailed demons sealed inside them. They include the title character, Naruto, Gaara of the Desert, and Killer Bee (who contain the Nine-tailed Fox, the One-Tailed Shukaku, and the Eight-Tailed Ox respectively.) It works as stated above: they can't get out without the host dying, and if the host dies normally they take the beast with them, though the Kyubi at least, and possibly the others, will eventually reincarnate some time later. As a result, the beasts grant their hosts supernatural power to ensure their survival.
 * It's worth noting that being sealed in a human makes them potentially more powerful, as when they are free they're feral and unintelligent, but being sealed gives them the intelligence of their host (though it's unknown if they retain this intelligence if they manage to break the seal and escape).
 * It would seem that some of the tailed beasts are smarter than others, so this probably varies.
 * Teito Klein, the protagonist of Zero Seven Ghost, is Pandora's Box... and imprisoned inside Pandora's Box is the death god Verloren.
 * The main premise of Bastard!!
 * in Slayers whose are a can for Shabranigdo.
 * Gaav, the Demon Dragon King was also sealed in a human. However, the seal leaked.
 * It might be said that it leaked both ways, since this is what caused Gaav to revolt against the other demon lords in the first place. A common fan theory goes that the gods knew Humanity Is Infectious, and chose to imprison defeated demons in familial lines of people specifically as a failsafe, so that the Exclusively Evil would be diluted out over the generations.
 * In the series' backstory and novel series, are also people-shaped cans for pieces of Shabranigdo. Since Shabby was split into seven pieces, we can assume that there are four others like them that we don't know about.
 * Prince Endymion tries to do this with Metaria near the end of Pretty Guardian Sailor Moon but.
 * And in Sailor Moon proper, Sailor Galaxia sealed Chaos inside herself to protect the universe from it, but ended up turning evil from its influence instead.
 * A major plot-point in Shakugan no Shana. Artifacts of the Crimson World are often hidden inside 'Torches', who are sort of like temporary simulacra of people killed by Crimson Lords and placed to make their disappearance unnoticeable.
 * Hell Teacher Nube has a demon who tried to kill him in his childhood sealed into his left hand by his mentor Minako.
 * In My Balls, there is a powerful demon sealed in the main character's left testicle.
 * In Sorcerer Hunters, the main character Carrot.
 * In Inuyasha The Movie 2: The Castle Beyond the Looking-Glass, Kohaku is revealed to.
 * In Bleach, the Hogyoku is sealed by into person over the course of the series after realizing it can't be destroyed by normal means. Initially it's sealed in, and later on.
 * Tapion and his little brother in the last Dragon Ball Z movie had half of a beast each sealed inside them, and in turn they were sealed inside a magical music box, a wizard kills Tapion's brother and frees the other half from Tapion himself. In the end Goku manages to kill the beast without trapping it, which frees Tapion forever.
 * from Tengen Toppa Gurren Lagann is the evil variety, a sleeper for the anti-spiral.
 * In To Aru Majutsu no Index,
 * From The World God Only Knows, The Weiss.
 * Rosario + Vampire both plays this trope straight and inverts it. Inner Moka remains sealed by the rosary she wears, but
 * In Defense Devil,.
 * In Sasami: Magical Girls Club,
 * In Tokyo Mew Mew,.
 * In Deadman Wonderland, the Red Man is sealed inside.
 * Draig, a Welsh dragon is sealed inside the protagonist, Issei.

Comic Books

 * In Elf Quest, when Big Bad Winnowill finally gets killed, her spirit would be free to prey on the other elves... except that Rayek, the one elf who truly loves her and hopes for her redemption, pulls her spirit into his own to prevent her doing more harm.
 * In Johnny the Homicidal Maniac, Johnny is revealed to be a "Waste-Lock", a human that serves as a form of receptacle for the spiritual negativity that humans generate by their very existence. This turns out to be the reason why Johnny never ends up getting caught for any of the horrid things he does and also (partially) explains why he's so utterly messed up..
 * Etrigan the Demon is sealed by Merlin inside Jason Blood.
 * In Green Lantern: Rebirth, previous events involving Hal Jordan having gone kind of Ax Crazy over the loss of his hometown, killed most of the Green Lantern Corps, renamed himself Parallax, and eventually ending up as the host for The Spectre were retconned: according to the new telling, Parallax had always been an entity unto itself, and possessed Jordan to use his power and anger for its own purposes. The Spectre getting involved turned the whole situation into more of a person-shaped-can scenario, with Jordan as host for both of them but the Spectre serving to keep Parallax stuck within him and unable to escape or exert any real control.
 * Marvel Comics has legendary Planet Eater Galactus, who acts as the seal keeping the Eldritch Abomination Abraxas imprisoned and not destroying the multiverse. He only needs to eat planets in the first place because the seal is powered by his metabolism.

Film

 * In Dogma, Almighty God herself took a vacation in the form of a mortal man. When that shell was beaten into a coma and put on life support, God was trapped inside. To be released, the shell had to be taken off of life support, and thus killed.
 * Calypso in Pirates of the Caribbean, sealed inside . She is fully aware of her true nature, however.
 * In the Tales from the Darkside movie a man meets a woman after surviving a gargoyle attack. The Gargoyle doesn't kill him on the Promise not to tell anyone. Years later he tells the woman now happily his wife with children. it's revealed.
 * Which is a plot recycled from the Japanese legend of the yuki-onna (as seen in the film Kwaidan).
 * Elvira, Mistress of the Dark for Elura in Elvira's Haunted Hills.

Literature

 * In Harry Potter,.
 * In the first few Discworld books, Rincewind has one of the Eight Spells of Creation hidden inside his head. It's described as trying to escape, and it has filled his head to the point of him being unable to learn any other spells.
 * After Snuff.
 * Felix Castor has a friend that suffers from this. The friend made the mistake of calling up what couldn't be put down, and Felix tried to exorcise it best he knew how -- only to find the thing had gotten tetherhooks into his friend's soul, meaning a proper exorcism would kill him. So he did the best he could and knitted them together.
 * In A Wizard Abroad,.

Live Action TV

 * The Hell-Goddess Glory, from Buffy the Vampire Slayer was imprisoned inside a mortal man named Ben, and protected by an enchantment that made any human (vampires and demons were immune) who learned of their connection to forget it quickly. In the end, Rupert Giles smothers Ben to put an end to Glory's threat forever.
 * In the Finale of the Fourth Volume of Heroes, Sylar was trapped in Matt Parkman's head, while Sylar's body walks around thinking it's Nathan Petrelli, with all of Sylar's and Nathan's powers. Yeah, that's gonna end well...
 * The angel Anna from Supernatural was reborn in a human body, and was completely oblivious to her great power, even without her Grace.

Video Games

 * In Sonic the Hedgehog, Princess Elise served as Iblis' "can", with her control over her sorrow being the lid -- if she cries, the can is opened and Iblis is unleashed upon the world once more. Her dying father sealed Iblis in Elise, a child, just before dying.
 * Later on, in the future, Blaze takes her place as Iblis' can. Course, then the Reset Button happened. Its a shame, it would've made a good plot.
 * She probably still is; It depends on how much of the multiverse Solaris tore apart while he was "Consuming all alternate timelines"
 * In Persona 3, the "sealed evil" is Nyx, a Cosmic Horror and Anthropomorphic Personification of death -- while the "can" just so happens to be.
 * At the start of Soul Nomad and The World Eaters Gig is moved from the Onyx Blade to Revya.
 * Gilvaroth, the Eldritch Abomination Big Bad of Jeanne D'Arc, is willingly put inside King Henry V's body to protect him from his political enemies by Duke Bedford, Henry V's own uncle. However, Gilvaroth cannot be destroyed As Long as There Is Evil, and a new vessel must be found. Enter Roger, who had the Reaper Ira sealed inside him earlier, and volunteers in order to atone. Things go awry as Gilles takes his place at the last second... with horrible consequences according to Real Life history. Whew! Gilvaroth gets around.
 * In Devil Survivor, it turns out Amane had a demon sealed inside of her when she was just a child. Unfortunately, said demon is one of the Bels... not the biggest of the problems caused by this, obviously, but considering the whole fight for the Throne of Bel...
 * Poor Amane also has a higher tier angel stuck in her to help balance out against the bel.
 * In Warcraft lore, Aegwynn was tricked into unwittingly becoming this for the spirit of Sargeras, the series' Big Bad. After defeating his physical form, his spirit entered her body and was later passed to her son, Medivh, who under its influence opened the Dark Portal to allow the Horde to invade Azeroth. Killing Medivh banished Sargeras' spirit back to the Twisting Nether.
 * In Diablo lore, it is customary for the Prime Evils to spend time inside human hosts -- either as a safety measure, or chained there against their will. When the Wanderer was tricked into using Diablo's soulstone on himself, he became the unwitting host of the Lord of Terror, and at some unknown point in time lost his will for good. In the distant past, a monk by the name of Tal Rasha decided to bind himself to Baal to imprison the Lord of Destruction forever and ever. It didn't go so well.
 * A very similar arrangement occurs in World of Warcraft. After Arthas is defeated in-game, the heroes realize that his willpower was the only thing preventing the Scourge from launching a frenzied, full-force attack that would annihilate all life on Azeroth. To prevent this from happening, there has to be a Lich King., agrees to take on the role of "Jailor of the Damned".
 * Wild Arms 2 has two of these. The first is a demon sealed inside the protagonist early in the game, which is kept in check by a magic sword . Since that worked out so well, the same thing is planned for the Kuiper Core, the main threat of the second disc..
 * Tales of Hearts has.
 * Dragon Age: Origins has a possible ending where.
 * The DomZ, local Eldritch Abominations of Beyond Good and Evil, consume the life-force of people harvested/kidnapped from the planets they attack..
 * In Disgaea 2: Cursed Memories,

Web Original

 * Michael Waite, famed horror writer in the Whateley Universe, turned out to be one of these. Locked inside him is The Kellith, a Great Old One foretold to wipe humanity off the planet and repopulate it with her spawn. Then he 'died' and changed into what everyone assumes is a vampiric girl mutant codenamed Carmilla. It Got Worse.
 * In Kickassia,  is presented as one of these to  . His inevitable release is a Crowning Moment of Awesome yet still vaguely disturbing.
 * In the SCP Foundation, SCP-231 plays this trope for extreme horror. They have to do SOMETHING to this absurdly young girl every few days to keep said evil inside. Word of God says that it's ten times worse than whatever your guess is.
 * Ancient Egyptian sorcerers in the Global Guardians PBEM Universe irreversibly bound Nephthys, Goddess of Chaos and wife of the Jackal-God Set, in the body of a twelve-year-old girl and sealed her into a Pharaoh's tomb, to be imprisoned for all time. Little did they suspect that the goddess would find such treatment to only be a temporary inconvenience.
 * Ancient Egyptian sorcerers in the Global Guardians PBEM Universe irreversibly bound Nephthys, Goddess of Chaos and wife of the Jackal-God Set, in the body of a twelve-year-old girl and sealed her into a Pharaoh's tomb, to be imprisoned for all time. Little did they suspect that the goddess would find such treatment to only be a temporary inconvenience.

Western Animation

 * Jean Grey was the "can" for Dark Phoenix in the X-Men animated series. Whether this is the case in the original comics depends on which retcon is considered canon at the moment.