Swallow the Key

A character swallows a key for safekeeping, whether to lock something or someone inside a device or room.

See also Stomach of Holding. Compare Treasure Chest Cavity.

Examples of Swallow the Key include:

Anime and Manga

A character in the Yu-Gi-Oh manga does this as part of his hereditary Human Vault job. It's one of the many Nightmare Fuel moments if you think about how he'd have been prepared for the role.

Comic Books

Judge Dredd did this in the comic where he fought the devil.
Y: The Last Man: Yorick does this trick as he is a trained escape artist, and he's taught it to his sister Hero, who uses a regurgitated key to escape prison.

Film

The forgettable Bio-Dome had one of the Idiot Heroes swallow the key to the titular biodome to keep the project going.
Apparently forced on one of Jigsaw's captives in the original Saw, so that another prisoner could be required to cut it out of his body to stop her own rapidly-approaching demise. No, contrary to what she'd been told, the key-swallower was not dead when she started cutting.
Done in the Coraline movie by the Other Mother.
In Puss in Boots, Jack swallows the key that locks the box where the magic beans are kept.

Literature

In Worldwar, due to the Lizards not understanding English expressions too well, they threaten to throw Rance into prison and "eat the key".

Live-Action TV

On an episode of Tales from the Crypt ("Carrion Death"), a criminal and a cop are handcuffed together. The cop is killed, but he manages to swallow the key before the criminal can get it, forcing the criminal to lug the dead cop along as he attempts to escape across the desert.
In Jekyll, there's a scene where Claire swallows the key keeping Hyde locked up. (In this case, it turns out she didn't actually go through with the swallowing, and the key stayed hidden in her mouth.)
In the CSI episode "Abra-Cadaver," the killer, a Stage Magician who was perfectly willing to kill his family members for the sake of illusions, does this at the end (although Grissom did think to check his mouth). Foreshadowed by a mention of the Harry Houdini example below.
The Suite Life On Deck: In one episode Mr. Blanket, the school's insane Guidance Counselor, handcuffs Moseby and Zack together and swallows the key.
The televised Zorro with Duncan Regehr twisted this—at the end of one episode, he chained up the alcade in the town square and forced the alcade to swallow the key.
Played with in The Mighty Boosh: in the episode "Jungle", Bob Fossil eats a key, slowly biting bits off it and chewing them.
Not done intentionally, but El Blanco the Graboid ate a gangster in an early episode of Tremors: The Series, who happened to have the key to a mob safety-deposit box around his neck at the time. In a later episode, the gangster's surviving associate returns to try to kill El Blanco and retrieve the key, hoping to empty the deposit box of its millions.
Done accidentally in Coupling, when Jeff Murdock holds the key to his girlfriend's handcuffs in his mouth and then does his best Darth Vader impression. He spends the episode trying to find a way to get it out before she realizes what's gone wrong.

Jeff: (on laxatives) If I take all of them at once, do you think there's a danger of liftoff?

Arrested Development: GOB tries to do this in the episode ""Key Decisions" to aid his escape from prison, but first has trouble swallowing the key and later is unable to pass it because of a Shy Bladder.
In one episode of Mystery Science Theater 3000, Pearl, Brain Guy, and Bobo are all trapped in a dungeon in ancient Rome. Bobo has the idea to regurgitate a key to undo their shackles, and Pearl compliments him for his ingenuity in lifting a key off a guard and swallowing it. Turns out Bobo didn't do that; he just thinks there's one in there because he swallows stuff all the time. It works, kind of -- he found a hairpin after a while.

Music

"Gatekeeper" by Within Temptation. Now that this guy has no metabolism to speak of and he's inside with the rest of them, well...

Tabletop Games

In Magic: The Gathering, Shu Yun swallows a key in this story:[1]

Western Animation

In one Tom and Jerry cartoon where they were doing their take on Robin Hood, Tom swallowed the key that went to Robin's cell.
Storm Hawks: Stork tries to keep the Raptors from getting their hands on a Graviton Crystal by swallowing it.
On the Looney Tunes short "Fin n' Catty", a cat corners a fish inside a shower, so he locks the door and swallows the key. Only then does the cat realize the shower stall is filled with water (which cats hate, as everyone knows) and he tries to punch the key out of his stomach.
In the Donald Duck cartoon "Trick or Treat", Don locks away all his Halloween candy and swallows the key. A witch then casts a spell on Donald's feet so that they kick out the key.
The Professor in Futurama did this with the spaceship keys to stop anyone from wasting fuel, only to "recover" them the next day.
In the Looney Tunes short "Hyde and Tweet", Sylvester did this after finally capturing Tweety. Only after Tweety's transformation does Sylvester realize that he's trapped.
In an early episode of Ed, Edd 'n' Eddy, Double D instructs Ed to hide the key. The guy slips the key between two slices of bread and eats it as a sandwich. Chewing and all.
Taz-Mania: Taz does this after he has cornered Francis X. Bushlad (who is disguised as an attractive female Tasmanian devil) in "A Young Taz's Fancy".

Real Life

Harry Houdini was reputed to do this with a handcuff-key in preparation for his escape act, then regurgitate the key when needed. One unsubstantiated theory claims that for the Daily Mirror challenge (one of his most difficult escapes) he used a clever variation; his wife Bess came onstage and kissed him for good luck - passing the key from her mouth to his. Whether this was true or not, however, was never confirmed.