"Fantastic idea for a movie. Terrible idea for a proctologist. Are you going to miniaturize me?"A plot that involves characters being shrunk to enter someone's body. Usually animated. Travel is often via submarine and scuba variants. Lighting is rarely a problem. Often has a time limit parameter, where either the person the characters go inside has a very short amount of time left to live, or the shrinking is temporary and the characters must accomplish their mission and get out before they kill the person by returning to normal size while inside of them. There will be at least one scene of just barely squeezing through some sphincter or valve as it closes. If there's a scene inside the stomach, expect to see random inedible objects scattered around for comedic effect (even if the character isn't an Extreme Omnivore) and/or food that has been swallowed whole that would normally be too large (such as whole burgers or hot dogs). These items tend to make handy platforms for any body explorers lacking a submarine, since shrunken characters usually suffer instant death upon contact with stomach acid (either that or they are completely immune). Protagonists being menaced by Seeker White Blood Cells, Monstrous Germs and/or giant tapeworms (well, giant to them) is also common. See also Incredible Shrinking Man. If there are normal-size invaders inside a giant's body, then you have been Swallowed Whole. Curiously, giant bodies tend to be filled with large open spaces for movement and even extended travel within, even if one was swallowed. Named for the granddaddy of them all, a movie co-starring Raquel Welch, which also spawned its own Animated Adaptation. An episode with this plot will usually contain some kind of direct homage to or parody of said film — a favourite being the infamous Clothing Damage scene. Bizarrely, the titles of such episodes surprisingly often reference Journey to the Center of the Earth instead, with the person's name or a noun that describes them in place of "the Earth". Not to be confused with the funkarific song by Lakeside. Or Coolio's similarly titled 1994 hit song. Compare and contast with Journey to the Center of the Mind, Ghost in the Machine, Animate Body Parts and Brain with a Manual Control. If somebody's body just happens to be the Adventure Town this week, you're probably just flying in a Womb Level.
— The Twelfth Doctor, Doctor Who, "Into the Dalek"
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Anime & Manga
- The Doraemon episode "Noby's Tough to Stomach" features Doraemon and Noby going inside Sue after she accidentally swallows an opal that was part of her mother's $50,000 dollar wedding ring while eating peanuts.
- In Dragon Ball Z, during the fight versus Buu, Goku and Vegeta (fused together as "Vegetto") get absorbed by Buu, and end up travelling through the villain's body so they can rescue their allies.
- Galaxy Angel has an episode where the team needs to enter Volcott's body because of some strange thing that make him change his body into several crazy stuff. Mint got haywire and it turns even crazier, which in the end result in Volcott turning into a baby.
- Due to some extremely trippy Applied Phlebotinum, the final battle of the IL arc of Get Backers takes place inside the opponent's body. Thus, hitting Makubex (who was in there with them...) caused the whole landscape to warp and shake.
- Gintama: The Tama Quest Arc which is also a parody of the Dragon Quest game franchise.
- In the third part of JoJo's Bizarre Adventure, when Steely Dan implants his microscopic Stand, Lovers, into Joseph's head, Polnareff and Kakyoin shrink their own Stands to the same size and enter Joseph's brain to battle Lovers.
- In episode 10 of the Sgt. Frog anime, Keroro's mouth becomes infested with microscopic, cavity-causing aliens, and a good chunk of the rest of the cast (including a robot duplicate of the sergeant mentally controlled by Keroro) shrinks down and enters his mouth to fight them off. Turns out there's a devil-winged chick inside there. In the end, it happens to Natsumi.
- In the Kyouran Kazoku Nikki episode "The Correct Way to Nurse", Kyouka turns the family, sans Yuuka, into a microscopic virus-fighting squad and takes them inside Ouka's body to remove an artifact that they tried to use to cure his cold.
- In the Parappa The Rapper episode "Did You Say You Didn't Sleep?!", Parappa's friend PJ gets infected by a virus, which causes him to grow into a giant every time he eats. This causes Parappa and his friends to get absorbed into his body and get rid of the virus in order to turn him back to normal.
- The Joseph Lai Mock Buster pseudoanime Space Transformers is about a mecha and its young pilots entering the body of a woman... who has a small galaxy inside her body.
- Time Bokan series Yattodetman does this in episode 37 where heroes and villains fight in the brain of a support character.
- The Osomatsu-san episode "We Caught A Cold" has each brother trade off taking care of the other five when they're all sick; when Jyushimatsu is the well one, he divides into a million microscopic clones of himself, which all invade the bodies of his brothers to fight the infections inside them. It works, but as a side effect, they all end up acting like Jyushimatsu themselves.
- Done in an episode of Kirby: Right Back at Ya! where Kirby goes into King Dedede to cure a cold.
- Wonder Beat Scramble is a whole series about this. Aliens seek the Secret of All Life by invading human bodies, and the heroes battle them using the titular ship Wonder Beat.
- Discussed (but ultimately averted) in Miss Kobayashi's Dragon Maid. Takiya suggests that Tohru could do this to cure Kobayashi's fever in chapter 42. Tohru shoots down the idea, saying that Kobayashi's body wouldn't be able to handle it.
- DC Comics:
- There was a comic, probably from DC's silver age, in which The Atom (Ray Palmer) had to enter the body of a patient to fight an infection. (Given his powers, it would be somewhat surprising to learn that this is the only time that happened.) Then Superman had to get himself shrunk and go in after him when the observers on the outside figured out that the microscopic creatures he was trying to get rid of were actually themselves fighting the infection rather than causing it.
- There's a similar story in a Justice League comic (I think #41, before Tower Of Babel) where the whole JL get shrunk by The Atom and enter someone's body. They lose their powers for some reason and are imprisoned by a race of tiny aliens.
- In this Disney story, Gyro shrinks Donald Duck (and a submarine) so he can go inside Uncle Scrooge and save his life.
- Ant-Man of The Avengers got to do this when he had to get inside his teammate The Vision in order to fix a malfunction inside him, during The Kree/Skrull War. It was done again, as a Mythology Gag, in Heroes Reborn.
- He did it again in New Avengers to retrieve a device on Luke Cage's heart, bringing Doctor Strange with him.
- In Action Comics #283, the Silver Age Supergirl, when she was affected by three Red Kryptonite meteors, got shrunk to microscopic size, which she used to her advantage to take care of some infectious viruses that were inside Dick Malverne's adoptive father.
- In The Simpsons comic, Mr. Burns has become ill from suppressing his need to burp for decades. To undo the blockage that built up in his system, Burns' scientists plan to drop a shrunken submersible into his body. Though the pod can be remote controlled, they still need a pilot in case of an emergency. Since even 'an anthropod will do' Homer is selected.
- In Archie's Sonic the Hedgehog #33, Sonic must shrink down and enter Rotor's body to fight off robotic germs.
- In a later issue of ROM Space Knight, Rom and Starshine reduce themselves by the use of Ant-Man's technology to submicroscopic size so they can enter the body of an ant and find a way to defeat a semi-mystical plague.
- Teenage Mutant Ninja Turtles:
- Volume 4 featured a variation similar to Futurama's: instead of shrinking down, the turtles sent millions of mentally-willed NanoTurtleBots into April O'Neil's body, which had been infected by millions of NanoBaxterBots.
- Later they have a straight example, going into April's sister's body to fight off "alien cancer".
- In ABC Comics' Tom Strong, Tom and his gorilla sidekick Solomon have to shrink themselves to enter the body of the malfunctioning robot butler Pneuman (which is more complex than it sounds because Pneuman had originally been a Steampunk robot in the 1890's and had been upgraded continuously right into the 21st century, so his innards contained everything from gears to vacuum tubes to atomic reactors to nanites).
- The Annual issue of Transformers: More than Meets the Eye opens with a group of Autobots led Rodimus entering Ultra Magnus to destroy a colony of lethal nanocons.
- An issue of Wolverine and the X-Men had members of the X-Men shrink down and enter the body of Kitty Pryde to eliminate a Brood egg that had entered her system. Please note, that this is immediately after Hank just finished teaching a biology class on mutant genetics that took place in Toad's body with the same process.
- The tenth and final issue of the Madballs comic book published by Star Comics (a now defunct subsidiary of Marvel Comics) had the Madballs Touchdown Terror, Bash Brain, and Fist Face enter the body of their arch-enemy Dr. Frankenbeans so that they could cure him of a virus.
Films — Live-Action
- Fantastic Voyage, obviously. The scientist who perfected the technology in the USSR is wounded after defecting and has a bloodclot that can't be operated on externally, so a team goes in on mini-submarine. They only have an hour because the only man who knows how to solve the time-limit problem is the comatose patient.
- Godzilla, Mothra, King Ghidorah: Giant Monsters All-Out Attack!: Towards the end of the film, Godzilla has killed all three of the Guardian Monsters, and the future looks bleak for Japan. The Humans decide to launch a submarine to attack Godzilla with a missile which can drill through things, but Godzilla eats the submarine. The Captain has a Heroic Blue Screen of Death, but gets encouraged by the spirit of his daughter to adapt his plan. He fires the missile at Godzilla's throat from the inside, and escapes through the massive wound. Godzilla tries to fire his Atomic Breath, but it escapes through his throat instead, making the beast explode.
- The MovieInnerspace, but its less, "lets enter the body to find a problem", and more "lets find the tool that can allow me to exit before I run out of air."
- In a rare permanent case, the film Osmosis Jones and the cartoon series it spawned were about cells, germs and viruses living inside a human being as if they were citizens of a city.
- According to the trailer for the Australian documentary/film, That Sugar Film, presenter Damon Gameau shrinks down voluntarily, to go inside of actor Brenton Thwaites's body and examine the effects that sugar has on the heart and liver.
- Also, in a metaphysical fashion, when a shrunken version of Gameau goes inside the head of a larger version of himself, to examine the effects that sugar has on the brain.
- In The 13 Ĺ Lives of Captain Bluebear the main character that gives the book its name must venture through a giant's brain in order to get to the other side of a mountain chain, as the giant has
diedfallen asleep and its head is blocking the pass through the mountains.
- In A Wind in the Door, Meg Murry and several other characters shrink to microscopic size to enter Charles Wallace's mitochondria and save him from the rebellious farandolae destroying him from the inside.
- In the fifth novel in the Young Wizards series, Wizard's Dilemma, Nita and Kit travel into the body of Nita's mother, though they do so in a metaphysical manner rather than by shrinking themselves, with her body's metaphysical representation taking on the appearance of New York City.
- In "The Journey", several members of the team chase some really tiny aliens inside Marco's body with the help of a convenient shrink ray. This is made more complicated by the fact that Marco can shapeshift, and everyone is nearly crushed to death when he turns into a cockroach.
- Note that Marco's morphing was dangerous to the Helmacrons too, not just to the Animorphs. So if they had thought of it, they wouldn't have had to go to all the trouble of going inside Marco, they could have just had Marco morph repeatedly, as long as it took to get the Helmacrons to surrender and come out of his body. Naturally, though, that wouldn't have made for a dramatic story...
- In "The Journey", several members of the team chase some really tiny aliens inside Marco's body with the help of a convenient shrink ray. This is made more complicated by the fact that Marco can shapeshift, and everyone is nearly crushed to death when he turns into a cockroach.
- Show Within a Show version: in Dream Park, one of the park's many popular attractions is the Mr. Digestion roller coaster.
- Besides the film novelization that he wrote (which is in itself notable for being a movie tie-in that's still in print over forty years after the movie was in theaters), Isaac Asimov wrote a Spiritual Sequel novel in the 1980s called Fantastic Voyage II: Destination Brain.
- In Journey to the West (and by extension most adaptations thereof), Sun Wukong shrinks himself and enters Princess Iron Fan's body by hiding in her soup.
- In the first The Paper Magician book, Ceony winds up shrunk down and traveling through Thane's disembodied heart. As she travels, she phases back and forth between his physical heart and his metaphorical heart (desires, fears, etc.), making this an unusual hybrid with Journey to the Center of the Mind.
- The story "The Space Cow" inverts this; a normal-sized veterinarian enters a gigantic alien organism to attempt to diagnose its apparent illness. The animal is perfectly healthy, it's just lethargic because its young are ready to leave its stomach and begin independent living.
- In the cartoon segments of The Aquabats! Super Show!, the band shrinks down to infiltrate Jimmy the Robot's body in order to rid him of his parasites that make him malfunction.
- Joked with in the opening scene of the Community episode Conventions of Space and Time, when Troy explains to Britta that them dating might cause Abed to relapse into another meltdown, and have to resort to this trope to bring him back. Abed already knew, but didn't say anything because he liked the donuts that Britta brought to their apartment.
- In Cosmos: A Spacetime Odyssey, Neil shrinks the Ship of the Imagination down to cellular level to fly into a brown bear's bloodstream, eventually traveling to the ovaries where he can explain how genetic mutations gave rise to polar bears.
- Doctor Who:
- In the Fourth Doctor serial The Invisible Enemy, miniaturized clones of the Doctor and Leela enter the Doctor's body to fight a virus. They fail, but clone-Leela's dissolving corpse imbues the Doctor with immunity.
- In the Twelfth Doctor episode "Into the Dalek", the Doctor, along with Clara Oswald and some human soldiers enter the outer-shell of a malfunctioning Dalek called Rusty.
- Farscape has an episode featuring a Budong, an animal so big that an entire colony of people could live in its corpse collecting the minerals produced in the stomach, with the obvious problems of gastric juices and other treats still in common.
- Spoofed in an episode of Fur TV when Lapeño, Mervin and Fat Edís Identical Cousin enter Edís anus after he overgrows due to infected food.
- Another live-action example is an episode of Homeboys In Outer Space.
- The premier episode of the series adaptation of Honey, I Shrunk the Kids did this accidentally when the family's fully submersible (just in case) minivan wound up inside Grandpa. They did some impromptu cholesterol removal with the laser windshield de-icer, prompting the mother to ask "Why aren't we richer?"
- Kroll Show has a particularly jarring version of this when Bobby Bottleservice, Peter Paparazzo, and Gian shrink down and enter Bobby's own body, in order to rid himself of his love for Farley.
- In one of the more clever Lost in Space episodes, Will Robinson and Dr. Smith find a severely malfunctioning robot who has become a giant due to his problem. The two have to physically enter the robot's body to fix him. However, the major complication is that they know that the second they are successful, the robot's body would start shrinking to normal size and they would have only seconds to escape before they are crushed. Naturally, the pair escape just in time before it was too late.
- The Middleman episode "The Clotharian Contamination Protocol" had Wendy go inside Ida's body to stop nanobots from making her explode. The snarky subtitles referred to it as "Like Fantastic Voyage. Or Die Hard in an Android".
- There's an episode of The Mighty Boosh called "Journey to the Centre of the Punk", when punk Vince is infected with a Jazz Virus, and Howard and Lester are shrunk in order to destroy it. This is probably the strangest one ever, especially the antibodies singing a song with Howard while he's trying to convince them he's their friend.
- Disney's Mighty Med has an episode where an envious Kaz uses a shrinking ray on Oliver as revenge for "stealing" his crush. It just so happens that a superhero with metallic skin has fallen ill and, as his skin makes x-rays and injections impossible, the only way to find out what's wrong is to send Oliver inside him. It turns out to be the superhero's arch-enemy, who had shrunken himself down to destroy the hero from the inside.
- In the Mr. Young episode Mr. Heart, Adam and Derby shrink down and enter Echo's body without her knowledge to fight a flu virus and allow her to go on a date with Adam that same day. Of course, they do have to find a way out again...
- When they do get out and return to normal size, Echo accidentally shrinks Adam, Derby, and herself. The three of them are accidentally swallowed by Slab, who is seen entering the bathroom during the ending credits, remarking that his favourite stall is free.
- Sabrina the Teenage Witch:
- In "No One Knows Libby Like Sabrina Knows Libby", Sabrina enters Libby's brain.
- In a later episode, Sabrina went inside herself to make room in her heart for a new beau.
- Star Trek: Deep Space Nine episode "One Little Ship" played with this by having a space anomaly shrink down a runabout. While O'Brien and Bashir weren't inside a human body, they were on board the Defiant during an attack by the Dominion and many of the same issues applied. One key component of the shrinking plot was that the ship had been shrunken at the molecular level- this meant that the air outside the ship would've been fatal to them if they had tried to breathe it due to the size of the molecules.
- In an episode of Ultra Seven entitled "The Flower Where Evil Lies", an alien insect called Darii gets into the body of a young woman related to one of the Ultra Garrison's members. Ultra Seven miniaturises himself, and enters the girl's body so he can fight the insect and save her life.
- Ultraman Eighty had two episodes where 80 did this. The first was "The Visitor from Space", where an old friend of 80 named Alma comes to Earth to study negative energy with her snail-like Jakki. However, Jakki absorbs too much negative energy and goes rogue until it is accidentally consumed by a zoo elephant, transforming the elephant into the giant monster Zuruzlar and forcing 80 to shrink himself and go inside Zuruzlar to subdue Jakki. The second was "I'm a Monster, You Guys!", in which a boy named Tetsuo eats an alien seed on a dare and is turned into a child-sized monster by it (though he still acts and thinks like a kid). The climax sees 80 shrink down and go inside Tetsuo to defeat the space plant.
- An episode of Weird Science has Chett eating a map to a house party that Wyatt and Gary were invited to. Wyatt and Gary shrink down, along with Lisa, to go inside Chett to retrieve the map. Hilarity Ensues.
- In Wizards of Waverly Place there's an episode where Mason, Alex's ex boyfriend swallows Dean, Alex's other ex boyfriend.
- The song Samut and the Dragon (found in Peter Alsop and Bill Harley In the Hospital) details a young boy with cancer who uses imagery to help his body heal. Every evening he dresses up like a knight and rides a white stallion into his own body, "by the bloody steaming rivers... through the mighty sinew forest, under tendon trees and bone," until finally he finds the cancer, a dragon, and uses his "healing sword" to strike it down, leaving his body to heal in peace. Of course, the dragon's always back by the next evening, but one hopes it's getting a little weaker.
- The music video for the song Special K by Placebo acts as a kind of homage to the film Fantastic Voyage. The music video takes place at an unspecified laboratory where the lead singer, Brian Molko, is shrunk and sent into the body of drummer Steve Hewitt, in order to locate and destroy a clot somewhere in his brain.
- The last episode of Season 2 of Mitch Benn's Crimes Against Music is called "Journey to the Centre of Rick Wakeman", and is about Mitch and his friends doing exactly that in an Affectionate Parody of Wakeman's "Journey to the Centre of the Earth" Concept Album, because it's the only way to stop war between England and Wales. Or something.
- In Series Three of Old Harry's Game, Satan and the Professor take a journey into Scumspawn's brain, discovering it to be a wide empty space, containing only tumbleweed and lumbering demon-thoughts. The title of this episode does somewhat reference the Trope Namer- 'The Reasonably Fantastic Journey'.
- Disney Theme Parks:
- EPCOT used to have a simulator ride called "Body Wars" based on this plot until 2007, when they closed down the entire pavilion that used to host it. It followed the travels of Dr. Cynthia Lair (played by Elisabeth Shue) as she studies how white blood cells react to a splinter.
- There was also a half-"Fantastic Voyage" Plot, half-Journey to the Center of the Mind attraction in the same pavilion, called "Cranium Command."
- Preceding both of them is the former Disneyland ride Adventure Thru Inner Space.
- At the Futuroscope, the Virus Attack dynamic movie brings you inside a patient's body in a mission to kill the nasty virus.
- There is a level in Devil May Cry 3 which takes place in Leviathan's body. Leviathan isn't big enough to hold all of that space, but his in-game profile says that his body serves as a gateway to the "jealousy hell" (in a nice Shout-Out to Leviathan's traditional role as the patron demon of envy).
- The Doom user mod DTS:T featured a level like this with the player wandering inside a human body- although to keep the level playable, the anatomy was incredibly bizarre.
- In one of the missions in Elite Beat Agents, the EBA enter a track star's body in order to encourage his immune system (anthropomorphized as a nurse) in its battle against a rather nasty virus.
- In the original Japanese game, the Ouendan squad helps antibodies fight off what appears to be food poisoning in a musician.
- In Final Fantasy XIV, players have to exploit this trope during the fight against Cerberus in the World of Darkness. Anyone who stands in Cerberus' sticky drool will end up chomped and instantly killed; however, if they let the Gastric Juices hit them with the Mini debuff first, they'll be swallowed whole instead and get a chance to punch the daylights out of Cerberus' stomach lining, causing the beast to collapse and leaving him vulnerable.
- The text adventure game version of The Hitchhiker's Guide to the Galaxy included a sequence where Arthur would find himself exploring his own brain.
- La-Mulana: The Ruins of La-Mulana are the Mother's body, and the true form of the final dungeon is a hybrid ruin/Womb Level
- Done twice in Ōkami. First, a shrunken Amaterasu has to enter the Emperor's body, through his mouth, to stop whatever it is that is making him exhale a noxious gas. A much longer trip involves a full-sized Ammy leaping down the gullet of the Water Dragon and exploring its innards, causing such wounds in the process that the Dragon dies from internal bleeding.
- The ZX Spectrum game Blood And Guts, in which a miniaturised character must collect bits of a submarine and reconstruct it in the brain in order to escape through the eye, all the while using a laser to fight infections, random white blood cells to clear growths, and collecting red blood cells for oxygen. Eventually Quicksilva decided to abandon all pretense and re-released the game as Fantastic Voyage.
- The plot of Mario & Luigi: Bowser's Inside Story has the brothers working with Bowser after the latter ended up sucking them up inside of him.
- In Moshi Monsters, the "20,000 Leauges Under the Fur" mission has Elder Furi be rendered sick and the monsters must shrink themselves and go into his body to remove Glumps that are in there.
- Gears Of War 2 has Delta Squad swallowed whole by a giant riftworm that's been sinking human cities. Marcus and the gang have to kill it from the inside out using freaking chainsaws.
- Bodyworks Voyager was an educational game from 1994 that was set Twenty Minutes In The Future and involved a crack team of commando-doctors trained to pilot fighter ships that were shrunk and injected into a patient's body, where your task was to shoot germs. Considering this came out years before Trauma Center, some of the bugs were just damn HARD.
- The Full Motion Video game Microcosm was a space shoot-'em-up with this plot.
- Midgame in Final Fantasy II you are swallowed by Leviathan and must fight your way out of him.
- Rex Ronan: Experimental Surgeon, an anti-smoking Edutainment Game for the SNES, had the title character shrinking himself to enter the body of a dying smoker to eradicate tobacco-induced ailments and Mecha-Mooks sent by the evil tobacco company.
- Gradius spinoff Salamander was retooled in the arcade as Life Force, set inside a planet-devouring Eldritch Abomination named Zelos.
- Kingdom Hearts I has a Monstro Womb Level, which has more anatomical detail than the film it's based on.
- For some unknowable reason (wanting to make good use of the textures?) Breath of Fire II is in love with this setting: over the course of the game, Ryu journeys inside a whale (to kill the monsters nesting inside of it and wake it up), a tree (to cure its senility), and an overweight queen (to exterminate the calorie demons inside her organs.)
- The Intellivision game Micro Surgeon had this as its plot.
- In SaGa 2, the party must travel inside Kai in order to fight off micronized soldiers of Ashura and extract the Magi from Kai. While this saves her life, it also means that she can't heal you afterwards since the Magi granted her healing powers.
- The last part of Space Quest VI involves series hero Roger Wilco being sent into the body of his friend/love interest Stellar, to save her from being killed/possessed by nanites. Although Roger has a shrunken shuttlecraft for part of the voyage, much of the action takes place on foot; many of the puzzles involve figuring out how to navigate through Stellar's labyrinthian innards. Among other things, he uses digestive juices to break open a medicine capsule, carries out an improvised balloon angioplasty (using alveoli) to clear a path through a blocked glandular duct, rides a tapeworm through the small intestine to avoid being digested, and jabs her brain with a paper clip to trigger a debris-dislodging cough.
- Amiga game Vaxine had you fighting diseases within different organs of the body, only the playing field was an infinite chessboard and the diseases were represented by bouncing balls.
- Yoshi's Island has a boss fight which features this trope: you're shrunk down to bite-size by Kamek and have to fight your way out of Prince Froggy's stomach.
- In Irem's shooter X Multiply, the spaceship X-002 gets miniaturised and injected into a space colonist's body to defeat an alien virus. You even get to see the X-002 coming out of the tip of a syringe at the very beginning of the game.
- The 1983 Apple II game Microbe. A miniaturized submarine and crew are injected into a patient's leg vein. They must proceed through various organs and blood vessels to the brain, where they will fix the patient's problem. Certain organs provide specific benefits: the submarine can refuel in the liver and get more air in the lungs.
- Ratchet & Clank: Size Matters has a level where Ratchet must travel inside Clank in order to reboot him after he is attacked by Technomites.
- Awful Hospital: "Endoshifts" let people enter worlds derived from bodies,note shaped by the concepts they encountered during their lives. In the Inert Sub-Concept Vessel arc, Fern inadvertently stumbles into a zone spawned from the corpse of one of her alternate selves. It's also used as a diagnostic tool.
- Done in The Non-Adventures of Wonderella here.
- Done in Work Sucks here. When your boss won't see a doctor, the only logical solution is to shrink down and let him swallow you to help remove parasite causing it.
- In the Super Mario Logan episode, "Jeffy Gets Stung By a Bee!", Mario and Brooklyn T. Guy believe that Jeffy swallowed the rare Banana Butterfly, which, when digested, causes the victim's arms to fall off and the victim to turn into a banana, so they shrink themselves down to microscopic size and pilot a microscopic submarine to get the butterfly out of Jeffy's stomach. When it turns out that Jeffy swallowed a bee, they are angry at Jeffy for making them waste their time on him. Then it turns out that Jeffy really did swallow a banana butterfly along with the bee.
- In one episode of The Adventures of Jimmy Neutron Jimmy and Sheen go inside Carl's body in order to get DNA so that Jimmy can make a cure to an illness. Of course, there is then the trouble of how you get out... But they soon decide that they should make Carl sneeze them out.
- An episoe of Alf Tales taking advantage of the Little Red Riding Hood story has Alf traveling inside the wolf's body.
- The episode of Alvin and the Chipmunks, "Inner Dave", where the boys are accidentally shrunk by one of Simon's inventions. They end up going inside Dave's head in order to try telling him what happened.
- Aqua Teen Hunger Force, "Unremarkable Voyage": After Meatwad swallows an experimental computer chip, Frylock shrinks himself to go in and get it. Thanks to a few screw ups, both he and a miniaturized Carl eventually wind up inside Master Shake. They then have to beat their way out of Shake's eye, killing him in the process. No worries though.
- Archer episode "Drastic Voyage" had the group use the shrinking technology to remove a blood clot from the man who invented the shrinkray. Unfortunately, Krieger interfered with the procedure, causing them to be injected into the man's foot, rather than his neck. It's about the first example when they fail, returning to their size while still in the man's head, killing him instantly.
- Arthur: Doesn't really happen, but in "Buster's Breathless", Buster Baxter tries to explain his asthma by telling his classmates to imagine themselves inside his lungs.
- The Batman: The Brave and the Bold episode "Journey to the Center of the Bat!", starring Aquaman, the Atom, and the cutest lymphocyte EVER.
- In one episode of the Beetlejuice cartoon, BJ got a bad case of Easy Amnesia after being hit by a falling satellite, and a psychiatrist shrinks himself, Lydia, and a duplicate of Beetlejuice so they can enter the original BJ's body, work their way to the brain, and fix the problem.
- Bill & Ted's Excellent Adventures: Bill and Ted go inside their Gym teacher's body. They even befriend the pretty female Anthropomorphic Personifications of his lungs. Makes Sense In Context.
- Camp Lakebottom: A miniaturized McGee ends up inside Buttsquat in "Buttastic Voyage".
- This also forms the plot of a Captain N: The Game Master episode, in which all the heroes other than Captain N shrink down to enter his body to help him fight off a disease.
- On Captain Planet and the Planeteers, the shrunken Planeteers battle microbes from polluted water inside Kwame after he accidentally drinks them.
- In an episode of CatDog, Cat goes inside his and Dog's own body after Cat eats Dog's pet fish. Very, very confusing if you haven't seen it.
- Multiple episodes of The Cat in the Hat Knows a Lot About That! have the Cat take Sally and Nick on a tour of someone's body in a shrunken Thingamajigger to learn about various body parts, such as the stomach, the heart, the nose, etc.
- The titular character of Chowder once ate a really sour fruit that made his lips pucker so tight that he created a portal that sucks himself into his own mouth. He then had to get rid of the pieces of fruit in his mouth, led by "Lord Souron", with sweets and a musical number to get back.
- Codename: Kids Next Door has "Operation S.P.R.O.U.T," in which Numbuh Four accidentally eats a Brussels sprout, and Numbuhs One, Two and Five shrink themselves to retrieve it.
- There is an episode of Cow and Chicken called Journey to the Center of Cow where Chicken was accidentally swallowed by Cow. This is a rare example of when some one was not shrunk.
- Danger Mouse has an episode where DM and Penfold use Baron Greenback's shrink ray to follow the villain inside Colonel K. to defeat the toad's terrible plot.
- Dex Hamilton: Alien Entomologist has an episode where the crew have to travel into the body of sick Space Whale in order to cure it.
- Dexter's Laboratory where he goes inside Dee Dee's body to combat a cold she's having. He ends up in the dog instead.
- The Fairly Oddparents: "Tiny Timmy" - Timmy shrinks down to microscopic size to do a biology report and ends up inside Vicky.
- Family Guy: Stewie shrinks himself and enters Peter's body to prevent his parents from reproducing. Apparently all sperm are their potential human counterparts flying around in fighter jets. Stewie also meets a comrade in sperm form who shares the same sadistic tendencies as Stewie. He actually gets born in a later episode after Peter donates sperm.
Prof. Farnsworth: That would require extremely tiny atoms, and have you priced those lately? I'm not made of money! Leave me alone!
- In "Parasites Lost", although with a twist: Zoidberg and co. are sending miniature robot replicas of themselves inside Fry. Gives Leela (well, a miniature thereof) the opportunity to slice and dice them up without any long-term ramifications. Farnsworth's scientific explanation as to why they don't shrink themselves:
- The "tiny robots" method also allows for an unusual take on the trope - later in the same episode, Fry creates his own tiny robot, thus effectively allowing him to go inside his own body (though this was earlier done on Doctor Who, with clones instead of robots — see above example).
- In one episode of Gawayn, Gwendolyn and Roderick have to travel inside the body of a dragon to kill the germ causing its acid reflux.
- Godzilla: The Series had Nick and Monique venture inside Godzilla Jr / Toonzilla. For obvious reasons, shrinking wasn't required.
- In one episode of The High Fructose Adventures of Annoying Orange, Orange and the other fruits are shrunk down and sent inside Nerville on a minituarized fruit cart to remove a laser that has been implanted in his brain by the broccoli aliens. It Makes Just As Much Sense In Context.
- Invader Zim miniaturized himself and his spaceship to go invade Dib's brain after Dib manages to get proof of Zim's alienness in the episode "Nanozim".
- Dib then swallowed a nanobot and had Gaz remote control it, eventually leading to Dib's robot and Zims robot fighting near Dib's brain.
- An episode of the '90s Iron Man cartoon does this; Hawkeye's spine is injured in a fight, and Tony has a technological fix but no way to safely insert it. So naturally he goes for hand-delivery. This is further complicated when a similarly-shrunken Ultimo tags along.
"You're giving him a heart attack!"
(Tony is trapped in a ventricle) "Yeah, and it's me it's attacking!"
- The Lilo & Stitch: The Series episode "Poxy", where they must chase after an experiment of microscopic size that is inside Pleakley's body.
- Several Looney Tunes shorts inverted this, by sending Bugs Bunny or another character running over and through the body of a giant as if it were a building (including pulling shades down over the giant's window-eyes). These no doubt influenced The Ren & Stimpy Show version below.
- The Magic School Bus once took a tour through the human body in one of the books that spawned the TV series, and then five times in the TV series: Arnold was the "victim" in the book and the show's adaptation of it ("For Lunch"), with him accidentally ingesting the shrunken bus while eating a snack, while Ralphie and Ms. Frizzle had their turns as well, to investigate the body's immunity system ("Inside Ralphie"), and muscular systems ("Works Out") respectively. Then they wound up going inside Arnold again to figure out what had made his skin turn orange ("Goes Cellular"). Finally, Arnold's cousin Janet gets her turn when the class goes inside her nose to study smell ("Makes a Stink"). There was also a computer game where you- you guessed it- go inside Arnold. Poor kid.
- In "Gets Eaten", they go inside a tuna fish, and in "Cracks a Yolk", they go inside a chicken. (And get laid.)
- The Mega Babies episode, Inner Ear Inferno involves Meg and Buck being shrunk and travailing inside Derrick in order to find the cause of his ear infection.
- One episode of the Mickey Mouse series of 2013-'14 is called "Down the Hatch", in which Mickey Mouse and Goofy are accidentally miniaturized by a Shrink Ray and then are inadvertently swallowed by Donald Duck. They explore his body , but when he learns they are in there, the duck tries all he can to get them out. In the end, as the shrinking effects wear off, Mickey and Goofy emerge from Donald by way of a giant egg, laid by Donald, a male duck!
- In the "Mundane Voyage" episode of Ralph Bakshi's Mighty Mouse: The New Adventures, Mighty Mouse is miniaturized and sent into the President's body.
- Done in Mona the Vampire, in the episode "The Sam n' Ella Infiltration", to enter the body of someone who is sick.
- A episode of Muppet Babies had Kermit, Piggy, Gonzo and Skeeter use their imaginations to shrink down to germ-size and give Scooter's bumbling immune system a hand when he catches a cold.
- The New Adventures Of Huckleberry Finn has an episode "The Mission of Captain Mordecai" where the three main characters, Huck Finn, Tom Sawyer and Becky Thatcher get swallowed by a giant whale while trying to escape a mad Ahab-like sea-captain who was trying to force them to be his new crew in his mission to kill said whale. To make matters worse, the giant whale also swallows the captain when he falls overboard while trying to harpoon it, and the rest of the episode deals with the young trio trying to evade the murderous captain while endeavoring to find a way out of the beast, which they finally do by climbing out its blowhole, the whale helping them along by blowing them out.
- In the Oggy and the Cockroaches episode "Globulopolis", while Dee Dee is swimming in a cup of yogurt, Oggy drinks it up, and Dee Dee along with it. Dee Dee then travels around the insides of Oggy and discovers white tiny ghost-clones, repeatedly punches Oggy's bladder as if it was a punching bag, and makes his stomach rumble by eating consumed fish inside it. In the end when he gets out, he ends up in Oggy's nose and flies into Jack's mouth along with Joey and Marky.
- In the Penn Zero: Part-Time Hero episode "Totally Into Your Body" Boone and Sasha were teleported into a sick Penn's body.
- Phineas and Ferb: On the episode "Journey to the Center of Candace", When Isabella's dog Pinky eats her sash, the boys try to go inside and retrieve it, but are accidentally eaten by Candace.
- Pinky and the Brain did this in order to foil an intelligibly-enhanced cat's Dance Sensation plot from being carried out properly by a band, by shrinking themselves and letting themselves get ingested by one of the band members. Unfortunately for them, they get eaten by the completely wrong guy, but they made the best of the situation by having the guy stand in for them.
- Done also in the comic book, in which they attempted to enter the President's brain, but ended up inside the First Dog.
- Quack Pack had an episode where a germ-loving scientist invades Donald's body, with Huey, Louie and Dewey being shrunk and sent inside their uncle in order to stop him.
- The Real Ghostbusters's Episode "Mean Green Teen Machine" has Egon giving a conference inside a human vein (as part of a Dream Sequence).
- ReBoot, "The Great Brain Robbery": Megabyte miniaturizes a mercenary named Mouse and his flunkies Hack and Slash and sends them to probe secrets from Bob's brain. Except they accidentally end up in Enzo's body instead, and Bob goes in after them.
- In the Regular Show episode Cool Cubed, Thomas drinks a slushie which gives him extreme brain-freeze, and Mordecai and Rigby are sent into his body to thaw his brain out. His brain looks like a frozen wasteland.
- Inverted on a later episode of The Ren & Stimpy Show called "Blazing Entrails"; a boy genius inflates Stimpy's body with a bicycle pump to ridiculous proportions, so that Ren can enter his body and find out why Stimpy is acting even stupider than usual.
- Rex The Runt, "Holiday in Vince": The dogs voyage into Vince's brain in a shrunken submarine in an attempt to cure his Random Pavarotti Disease (he frequently blurts out short bursts of opera). Eventually they find his tuning knob and retune him to Radio 4 (so he now blurts out gardening tips and the shipping forecast instead).
- Rick and Morty, "Anatomy Park": A Christmas episode about Rick sending Morty into a homeless man's body. Bonus points for being a simultaneous send-up of Jurassic Park, with the episode's plot revolving around the eponymous microscopic amusement-park inside of the hobo and the subsequent escape of the viruses held within. Bonus Squick is added by the hobo dying very early into the adventure, leading to a Fantastic Voyage inside the man's decomposing corpse.
- Rugrats, "The Inside Story": Tommy and co. go inside Chuckie to retrieve a watermelon seed, though in keeping with the relatively mundane setting, it's All Just a Dream.
- In a tongue-in-cheek episode, Samurai Jack once had to enter an ailing dragon's body to cure its devastating flatulance.
- Sealab 2021, "Craptastic Voyage": When Captain Shanks refuses to get treatment for a brain tumor because of his religion (a thinly-disguised parody of Christian Science), Stormy, Quinn, and Debbie Dupree shrink themselves to microscopic size and travel through Shanks' body to deal with it themselves. Subverted in that the episode's mostly Star Wars parodies, not Fantastic Voyage.
- In the 2nd season finale of The Secret Saturdays, the first final battle between Zak and Argost takes place inside the body of the super cryptid
- The plot of one of The Simpsons Halloween short, where the Simpsons travel into Mr Burn's body. Marge references Latex Space Suit when she asks why her suit is so flatteringly cut. Homer replies, "But Marge, that's what turns a Mediocre Voyage into a Fantastic Voyage!" (A reference to Raquel Welch in the movie.)
- South Park did a twisted parody of this trope, in which a gerbil named Lemminwinks had to find his way out of Mr. Slave's ass. And then it happened again with Paris Hilton.
- SpongeBob SquarePants: SpongeBob and Patrick once entered Squidward's body in order to remove a clarinet reed stuck in his throat. They also screw around with his brain. Unfortunately, after completing the task, Patrick accidentally made them re-enlarge while still inside Squidward. While he didn't burst, he did swell up big time from having a full grown submarine inside of him.
- Used in an episode of Teen Titans where Beast Boy turns into a bacterium to fight a computer virus that has taken over Cyborg.
- Used again in the sequel series (of sorts) Teen Titans Go!, where Cyborg gets sick again and Robin, who always wanted to do this trope, shrinks himself and the team with a shrink ray he bought just for this purpose and goes into Cyborg. Reality and much Squick ensues, however, when the show deconstructs this trope and Robin experiences how gross the human body really is and leaves without curing Cyborg, disappointed.
- On an episode of Tiny Toon Adventures, Buster, Babs, and Calamity shrink to enter Plucky's head and examine his brain to watch his fantasies.
- Totally Spies!: Sam, Alex, and Clover shrink down to the size of microbes to fight a trio of villains inside Jerry's brain.
- In the finale of Transformers Return Of Convoy, the Battlestars are swallowed by Star Giant and have to fight their way out from within.
- The Transformers has the episode "Microbots," which features Bumblebee, Perceptor, and Brawn shrinking down to enter Megatron and remove a power-enhancing crystal.
- Transformers Rescue Bots also has an episode in which Kade accidentally ingests some microscopic cleaning bots (Scrubmites), prompting the Rescue Bots to be shrunk down and retrieve them from his body.
- One of the many sketches from 2DTV sees Tony Blair in hospital suffering from an unknown heart condition. The NHS wants to send a shrunken team of scientists into his body to resolve the problem, but John Prescott steps on them. So John Prescott, David Blunkett (and his guide dog), Jack Straw and Tony's wife Cherie Blair are sent. Turns out that Gordon Brown is the one causing Tony's heart problems, in his latest attempt to become Prime Minister.
- In an episode of Ultimate Spider-Man, Spider-Man and Ant Man must shrink down into Fury's body that has been infected with Doc Ock's nano-bots.
- Uncle Grandpa once shrunk himself and Pizza Steve to get inside a kid's brain and make him better at video games.
- Invoked, discussed, and lampshaded in The Venture Bros. episode "The Diving Bell vs. the Butter Glider". For some reason, Doctor Venture is paralyzed, and they can't use an MRI because there's too much metal in his body, so the logical solution from Billy Quizboy is to get a submarine, shrink it down, and go inside to find the problem. Which turns out to be a clot in Doc's bloodstream caused by a previous shrunken submarine piloted by previous clones of Hank and Dean, whose skeletons are still there. The implication is that Billy was quick to suggest this solution because of what a sci-fi geek he is. He name-drops Fantastic Voyage as a "classic" and defends the quality of Inner Space, though his assistant dismisses the premise an old cliché.
- In Saban Entertainment's The Why Why Family, most of the episode segments with Micro and Scopo Why Why, baby Victor's uncles, involve going with Victor into his family's bodies via shrinking themselves. This is also justified because Micro and Scopo are experts on the human body and nutrition.
- In an early part-animated, part-live action ABC After School Special, "The Incredible Indelible Magical Physical Mystery Trip," a magical being named Timer (who would later appear on ABC's Saturday Morning cartoon block in a series of PSA spots) shrinks two children and takes them on a tour of their uncle's body to better understand the importance of health and physical fitness. A sequel, "The Magical Mystery Trip Through Little Red's Head" has Timer take two different kids on a tour of their teenage sister's brain to explain how the human mind works, 41 years before Inside Out.