Mariana: Don't pee in the water.Beck: (closing his pants really tight) Not this boy's pinto. Uh-uh. Not today!
Mariana: A candiru, a vicious parasite will swim up the urine into your pau.
Beck: Swim up my what?
Mariana: Your pinto. It'll swim up your ding-dong. And once it gets in, you can't get it out.
Beck: (stammers) Well, then what?
Mariana: They have to amputate.
A variation of Body Horror, where a creature basically forces all of itself into someone else, but through an established opening of the body (as in naturally, not a cut or piercing), even if it's not really an opening (like the navel). It could be the mouth (do not confuse with Force Feeding), the nostrils, the ear, or through orifices below the belt. Pores could even count.
Sometimes this happens in reverse, where something leaves a body through an orifice, implying that is how it came in, even if that isn't stated.
Ass Shove is the trope when that particular orifice is involved.
Not to be confused with Alien Invasion, which is one of the more common causes of this trope.
- In Dragonball Z, one of the first acts Super Buu commits after being formed is to turn entirely into pink goo, force himself down the throat of one of the humans that killed Fat Buu's dog and expand, blowing the guy apart from the inside. Brrr...
- Later tried again against Vegeto, who responded by beating the crap out of Buu who was still inside his body.
- This is how the larval form of the entities in Parasyte take control of their hosts, usually entering through the ear of a sleeping person to get at the brain. When the protagonist fell asleep with headphones on, his symbiote tried getting in through one of his nostrils instead. After he woke up, it had to settle for burrowing into his arm. He tied his headphone wires tight around his arm to keep it from burrowing up to his head, screwing up the transformation process.
- Getter Robo has the Invaders, a race of cosmic horrors who can invade people's bodies if they so much as bleed on them. Though most of the time they prefer to just dive into people's throats, or simply rip a hole in their torso and use that.
- Medusa in Soul Eater possesses an innocent girl in the suburbs this way, by turning into a snake and slithering into her mouth.
- And before she did it to the girl, she did it to a dog.
- She also does this with the snakes she controls instead of herself: if she can get something into an entry point to your body she can send in hundreds of snakes which let her track you wherever you are and can rip you to pieces whenever she tells them to.
- Happens too many times to count in Jojo's Bizarre Adventure.
- In the manga version of Ju-on, this is how Kanna meets her end when a bunch of possessed cats enter her mouth and tear her jaw off.
- In the DVD remake of one episode of Bakemonogatari.
- In Basilisk, one of the ninjas from the Iga clan whose power is to turn into a slug-like thing in the contact with salt kill a ninja from the Kouga clan by jumping in his mouth, inside his throat and breaking his neck.
- Done constantly to poor Sakura in Fate/Zero (with a pit full of worms) by her Complete Monster stepfather.
- Same for her uncle Kariya, who is also quite "intimate" with the aforementioned worms. The scene where he had a remarkably phallic worm forced down his throat was probably the most graphic Orifice Invasion of the series.
- The DC Universe 52 series answers a question no one ever asked before: can Orifice Invasion of a robot be made to look horrific? The answer? YES. Dear God, yes.
- In Calvin and Hobbes, one of Calvin's fantasy sequences involves a frog forcing its way into his mouth and being swallowed. Which leads to the punchline: he had a frog in his throat.
- The image example for this trope comes from The Piper #2 by Zenescope comics. The woman in question (Sandra) just had a poisonous snake slide into her mouth after putting her lips on a french horn's mouthpiece, all thanks to the Piper playing his lethal song outside her room. She dies.
- A (relatively) innocent example happens in PS238 when Polly Mer tries to stop a metahuman with Super Strength and Make Me Wanna Shout powers by wrapping herself around his head. Unfortunately his inhaling abilities are a bit stronger than expected. Polly states afterwards it's the first time she's felt what lungs feel like.
- Spoofed in Army of Darkness.
- The monster in Baby Blood enters a woman through her vaginal canal.
- Used with a snake in Collateral Damage by the Big Bad, to execute a spy.
- The fly that enters the nose of the main characters Drag Me to Hell.
- The Hidden: The alien parasite burrows into and out of mouths several times during the movie. One scene used a prosthetic head to show the process in gory detail; upon seeing that scene on film, the actor whose likeness was on the head was physically ill.
- A "bug" in The Matrix enters through the bellybutton.
- A monster in Poltergeist II disguised itself as a tequila worm to take over the dad. However, the dad overcame this and threw it up.
- The Decepticon Doctor (Scapel) in Revenge of the Fallen reads Sam's brain by sending a small robot up his nose.
- The slugs in Night of the Creeps.
- The slugs in the movie Slither enter their hosts through their mouths.
- In Sniper, Thomas Beckett (Tom Berenger) warns his partner not to urinate as they are wading through a waist-deep river, because small organisms will enter his urethra and dig in with spikes.
- Starship Troopers II, the low-budget sequel to the movie, introduced a breed of bugs that entered through the mouth to control the humans (it was also a convenient way to save on the special effects).
- The larval Ceti eels in [[Star Trek II: The Wrath of Khan]] enter through the ear.
- In the short film Ghosts, the Maestro (played by Michael Jackson) possesses the Mayor (also played by Jackson, believe it or not) this way.
- In The Island, the diagnostic sensors (which look like a cross between ticks and spiders) crawl into the body via the eyesocket.
- In John Carpenter's Prince of Darkness, the Anti Christ is a green liquid who enters into people via their mouths: the hosts then do the same thing to spread the possession, i.e. vomiting into other people's mouths.
- eXistenZ is played this way.
- Played for laughs when Bill and Ted's ghosts try possessing two men. They squeeze in through the ears.
- "I totally possessed my dad!"
- In Scourge, the titular black silverfish-like parasite enters through the navel.
- After he is blown to bits, Jason Voorhees's heart in Friday the 13th (film) evolves into a small creature which does this to take over bodies.
- In Flubber, the titular Flubber shoots into a Mook's mouth, wriggles around inside of him, and then explodes out the back.
- The titular Cat from Hell (a Stephen King short story adapted into the anthology Tales from the Darkside: The Movie) enters through the mouth of a hitman hired to kill him, causing that man to choke to death before the cat goes in all the way. This really goes with Rule of Scary in The Movie, where the cat is obviously way too big to do that.
- The babelfish of The Hitchhiker's Guide to the Galaxy enters the ear, although it's more helpful than other creatures of this trope.
- The creature in Piers Anthony's novel Firefly does this.
- In Animorphs, Yeerks take over human beings by way of infestation through the ear canal.
- Also Father in the Ellimist Chronicles, a giant sentient sponge (well, sort of) that sticks tendrils into the body (Not quite that way!) to keep its victims alive (or in the case of the dead, keep them from decaying as long as they remain attached) and giving it access to their minds.
- In Clive Barker's Confessions of a Pornographer's Shroud, a vengeful sheet-possessing ghost shoves its fabric "arm" down the throat of the gang boss who'd ordered its murder... then pulls it out, along with most of its enemy's alimentary canal.
- In the short story "Motherhood Redeems Women" by D. Douglas Graham, an aborted fetus decides to return to the womb by the same door he came out. Squick ensues.
- There's a story by Tanith Lee about a demon that takes possession of humans via their orifices, so to try and prevent being possessed one guy blocks all of his orifices, but forgets his urethra. Ow.
- In the Star Trek: Deep Space Nine novel "The Siege", an evil shapeshifter kills a Cardassian by ramming himself down the victim's mouth, then expanding inside. In a later novel, Odo threatens to do this to a Cardassian officer should he dare to disturb Odo's regeneration.
- The biotech of the villainous Yuuzhan Vong in the Star Wars Expanded Universe often does this. Frequently commented on are the living disguises known as ooglith masquers, which have feeding tendrils that insert themselves into the wearers' pores. Numerous creatures fit the trope more exactly by slithering into ears or eye sockets, or down the mouth.
- In Stephen Baxter's Space, the hero Malenfant is integrated with an android/computer system. Tendril-probes infiltrate him... essentially everywhere, and there is no attempt at anaesthesia. He is doomed to live for billions of years in this state unless he fails in the task for which he was converted, in which case a stellar event will occur that will kill every living thing in the galaxy except for archaeobacteria and slime moulds.
- The Fallen. Leviathan has people having their bodies taken over by making the creatures enter through their mouths.
- It's one of the trademarks of The X-Files.
- One Real Life example was in The Amazing Race, where one of the guy woke up partly covered by leeches, and one somehow crawled into his urethra.
- The prehistoric worm parasites in the revived The Outer Limits episode "From Within" entered (and later exited as they died) through nostrils, mouths and ears. One girl actually had a worm go in her right ear (complete with blood) and at the end of the episode have it come out her left ear without leaving her with any ill effects (other than a great deal of pain).
- Doctor Who TV Movie: the master in the form of a slug like creature crawls into the mouth of a sleeping paramedic to take control of his body.
- An episode of Lexx had space carrots that take over people's bodies by ramming themselves up their anuses.
- In a bit of a twist, through the mouth is the more pleasant way for a Goa'uld symbiote to enter a human host: Goa'uld normally enter through the neck, not wishing to see the expression on their future host's face. Only the Tok'ra, a breakaway group who only accept voluntary hosts, normally enter through the mouth.
- Non-Tok'ra will enter through the mouth to avoid leaving a visible scar, however—if they have reason to suspect they will be attacked if discovered.
- The creature that inhabits Helen Magnus of Sanctuary has a parasite exit through her ear canal after she dies. Based on the dialogue, it got in through her pores.
- A classic Night Gallery episode has a man hiring someone to do away with a rival by planting an earwig in his ear at night, where it will crawl into his head, constantly eating (see "Real Life" below) -- in a karmic slip-up he gets it planted in himself. In a million-to-one fluke, he survives weeks of agony when it crawls out his other ear. With the boldness of one who's been through Hell he owns up to his deed and claims he'd do it again...then he finds out the earwig was an egg-laying female.
- Hunting for mole lizards in Baja California, the host of Weird Creatures is told a local Urban Legend that these worm-like animals will invade the anus of anyone who defecates over their burrows.
- D&D 3.5 edition sourcebook Lords of Madness introduces a new (and decidedly creepy) aberration: the Tsochari (singular Tsochar), a mass of tentacles that bores into victims and can either coerce the victim into behaving itself by causing them great pain, or, kill the victim and wear the body as a disguise.
- And then there are hellwasp swarms that can enter a dead body and animate it... or enter a living body and force it to do what they want...
- And then there's the process of ceremorphosis, which a mind-flayer tadpole is inserted into the ear of a hapless humanoid (usually a captive human, orc or drow), which eventually turns them into a new mind flayer.
- And to crown the collection there's the DC 90 Escape Artist check from the Epic rules. Combined with Enlarge Person...
- Combined with the Exemplar class, who can among other things do stuff like substitute a Diplomacy skill check with Escape Artist, you can even do this and impress onlookers so much they will adore and admire you.
- These seem to be based on a creature from one of the Cugel stories by Jack Vance, implanted by a wizard to control the actions of said rogue.
- Daemites from BloodRayne force themselves into the victim's mouth, then take control over the body.
- Several of Las Plaguas were inserted at adult size into the mouth of the victims in Resident Evil 5 for quicker control of the hosts.
- The alien species in Microsoft's Freelancer entered a host through the mouth and effectively take complete control of the body, including the host's memories and personality traits, or at least enough so that nobody realizes that the person they're talking to isn't really the President anymore...
- In one of the dungeons in Pokémon Mystery Dungeon: Explorers of Time/Darkness/Sky, Grovyle is attacked by a Spiritomb, which took control of his body by entering through his nose.
- One of Shang Tsung's fatalities in Mortal Kombat 2 is forcing himself into his opponent's body, causing them to inflate to ridiculous proportions followed by the victim exploding into a massive shower of blood and bones.
- And then there are the Bonethieves...
- The Mysterious Shadows in Deadly Premonition sometimes do this.
- The Winter Windster from Wario World flies into Wario's mouth if he looks at him while his eyes are red.
- The Death Slug from The Visitor in it's larva/parasite form does this, allowing itself to be eaten or, taking the back door in order to absorb and messily kill it's host
- The...uh...nurses(?) in Oglaf use a "polyp of cleansing" to cure the unfortunate Ivan of poison. The phrase "open your food tract, mammal" is employed, followed by a very unpleasant-looking panel. Of course, given which webcomic this is, perhaps we should be glad it was his mouth.
- In an episode of The Venture Brothers, The Monarch threatens to dunk the Venture family in a river teeming with candirus. Bizarrely, Dr. Venture claims the candiru are a myth (making it unclear if it's a case of Did Not Do the Research by the authors of the show or Dr. Venture himself).
- There's an episode of Batman Beyond where the Villain, an amorphous woman named Inque, tries to suffocate Terry by forcing herself down his throat.
- In Code Lyoko, XANA's specters generally possess people by entering through the mouth or the ears.
- In episode "Franz Hopper", instead of possessing one specter tries to clog Jérémie's airways by entering his mouth and nose.
- In one episode of The Simpsons, Groundskeeper Willie fills the auditorium with rats in revenge for being humiliated. Bart warns Milhouse not to open his mouth; of course, Milhouse starts to say "What?", at which point half a dozen rats leap in.
- Played for Laughs in [[Avatar: The Last Airbender]]. Momo is missing, and Sokka thinks Appa ate him, so he crawls in Appa's mouth to see. Appa just spits him out.
- Done in Sylvester's first short Life With Feathers, in which a henpecked male bird wants to commit suicide, so decides to feed himself to the cat. Of course, Sylvester is suspicious about why the bird would want to do this, so he spends the entire cartoon running away, with the aforementioned bird chasing him and pleading to be eaten. Found here.
- Sym-Bionic Titan takes this to a disturbing extreme. Xishi, a squid-like monster about the size of an average human, climbs all the way down her victim's throat and forces them to speak the truth. What's really creepy about it is that Xishi's face is visible from inside the victim's throat.
- Carrie from The Amazing World of Gumball can posses someone by flying into their mouth and down their thorat.
- The Geonosian Brain Worms from Star Wars: The Clone Wars enter the victims through the nose, and take control of the body.
- A subversion occurs in Season4, when Obi-Wan voluntarily swallows a "vocal emulator", a spider-like device that changes his voice, in order to perfect his disguise as Bounty Hunter Rako Hardeen.
- The candiru. Unlike this fish, however, more parasites make a habit of leaving through various orifices, but they usually enter as eggs and grow inside the body.
- Generalizations about the candiru's hunting methods rest on very little evidence, as there has been precisely one documented case of a human attack, in 1997. In particular, it is not chemically sensitive to either ammonia (excreted by fish) or urea (by humans).
- There's also an urban legend about earwigs crawling into your ears (hence the name), although they don't actually do that.
- Earwigs, as well as spiders and other creepy crawlies, actually do prefer small, tube-like spaces, and will occasionally find their way into someone's ear canal. They'll usually just leave as soon as they discover it's coated with slippery and unpalatable earwax.
- Truth in Television: Some Argentinian torture methods during the Dirty War involved a bunch of naked people in a small room, in fetal position, forming a circle. Then, their torturers dropped a starving rat inside the circle the people were making. The rat would try to escape by entering someone's ass, literally.
- There are tales of this sort of torture from many different situations supposedly brutal in their methods. For instance, they say the Imperial Chinese did this from time to time, except that there was only one person and the rat was in a hot cauldron strapped to the victim's ass.
- This is how most scavengers consume carrion, as it requires the least amount of effort to get to the soft fleshy bits.