Exactly What It Says on the Tin. This trope describes one's ability to retract their limbs.
This is an ability common to creatures that possess a protective shell, which can retract their limbs within it as a natural mean of self-defense. Features such as retractable claws or teeth are also quite common, although for a more offensive use. More rarely, some creatures will be able to retract their legs or arms inside their body itself; in that case, it will most often be a case of either having Bizarre Alien Biology or being an Eldritch Abomination.
Aside from those uses, Retractable Appendages can also serve the purpose of camouflage, whether for the purpose of avoiding Fantastic Racism or as a way of Dressing as the Enemy. Most common examples include the fangs of vampires, the horns and wings of demonic beings, the abnormal features of Mutants, and the extra limbs of human-looking aliens. When Played for Laughs, expect Power Incontinence to strike, with the character revealing their hidden appendages at the worst possible times, and trying desperately to hide them.
This trope is actually often found in Real Life. Among the most well-known examples are turtles and snails, which are able to retract their limbs within their shells,note with the latter also able to retract their eyes and horns inside their body. On the same note, felines, especially cats, are known for their retractable claws. As such, if a fictional creature is based on one of these animals, they will most likely inherit this ability.
- Abraxas (Hrodvitnon):
- Minor example in The Keys Stand Alone: The Soft World when George becomes a nixie for a while. Paul notices that he doesn't have any genitalia in that form, and George deadpans, "It retracts. If I leave it out it attracts fish. It's useful to bring dinner over. Would you like to see it in action?" Paul can't tell if George is serious or not.
- White Sheep (RWBY): The Combat Tentacles that Jaune and his sisters are infamous for are typically hidden inside their bodies. Jaune mentions that it's slightly uncomfortable, but not really worth caring about most of the time.
- The electronic devices in The Brave Little Toaster all have retractable faces, with the exception of Radio, who for some reason actually doesn't have a face.
- Neiz from Dragon Ball Z: Cooler's Revenge has the ability to retract his head into his body like that of a turtle.
- Toothless from How to Train Your Dragon has retractable teeth, hence his name. In How to Train Your Dragon 2, he is revealed to also have retractable scales along his spine.
- In Lilo & Stitch, Stitch can retract his antennae, back spines, claws, and second pair of arms, which he demonstrates when taking refuge in a dog pound, as seen above.
- Gamera, the flying turtle, can retract all four of his legs into his shell, then cause fire to spray out of the holes, allowing him to spin around and fly. He can retract his head into his shell the same way, and often does so while flying.
- In The Hitchhiker's Guide to the Galaxy (2005), Zaphod retracts one of his heads into his chest from time to time.
- Inspector Gadget 2 has this happen to Gadget when he ducks a punch in the face at a bar.
- All of the Polichinelles from The Nutcracker and the Four Realms are able to retract their limbs and head into their torso forming a ball shape.
- An early Stephen Chow movie, The Royal Tramp, involves a battle with a Made of Iron villain who can even retract his manparts. However, Stephen's character, having grown up in a brothel, learns how to counteract this by shoving something up the backdoor.
- The title characters of Teenage Mutant Ninja Turtles (1990) all have the ability to do this. During the final Foot battle of the film, Mikey retracts his head into his shell to keep it from being taken off by a Foot mook's axe. "God, I love being a turtle!"
- In The City and the Stars, future humanity has been engineered so that male genitalia are stored internally when not in use.
- The Future Is Wild has the Flish with a retractable second mouth. The Slickribbon has the Flish's retractability brought up a notch.
- In The Haunting of Drearcliff Grange School, Speke has strange crablike shell-covered hands that have something resembling a mind of their own. At one point, her crab-hand fingers withdraw into her palms rather than risk touching a supernatural artifact. Speke herself is surprised, as they'd never done that before.
- In You Only Live Twice, James Bond visits a Japanese martial arts training facility where the fighters have been trained to retract their testes into a recess in their hip bone, making them invulnerable to a Groin Attack. (In real life, this technique is more attributable to body stance, with the pelvis thrust forward so that a good part of the buttocks is where the genitals should be.)
- Dungeons & Dragons: Giant Snapping Turtles are noted as being able to retract their legs and head into their shell, thus improving their armor class.
- Final Fantasy:
- In Final Fantasy IV, the turtle monster Cagnazzo is a creepy example of this. He can collapse to invulnerable shell form, even though his beefy humanoid arms and legs are clearly too big to fit in his shell.
- In the Dissidia Final Fantasy series, Kefka has six retractable wings that only extend when he uses the attack "Havoc Wing".
- In Kingdom Hearts, Sephiroth has a retractable black wing. It's implied in the Compilation of Final Fantasy VII series that his black wing is the same as in Kingdom Hearts.
- Genesis and Angeal from Crisis Core also have retractable wings.
- Generation V has the golem-like Golurk who is able to fly this way by retracting its arms and legs.
- Any Pokemon with the ability Withdraw.
- Darumaka in battle and in the anime can retract their limbs into their body, giving them the appearance of an egg. This is a reference to Daruma dolls (as their name indicates).
- One of Hoothoot's legs is retractable.
- Darkrai also has retractable legs.
- Soul Series: Algol from Soulcalibur IV has three retractable, kraken-like, clawed, finger-esque tentacles on each side that extend from his chest.
- The Amazing World of Gumball: It turns out in "The Gift" that, like her arms, Masami's long legs can be retracted into her body. It's where she wears the rainbow toe socks Harry got for her birthday. She wears them all the time she loves them so much.
- CatDog has the titular character retract its body like a snail, there's only one episode where the play it rather... gruesomely.
- Plasmo and Parsty from Plasmo are able to pull their arms in and out of their body, as part of the abilities of their species. They often default to having them kept inside when not in use.
- Filburt from Rocko's Modern Life. Justified that he is a turtle.
- Skull Island (2023): When the Kraken's tentacles are injured during the final fight, they retract back inside the Kraken's torso.
- SpongeBob SquarePants:
- Most species of turtles and tortoises are able to retract their legs and neck inside of their shell.
- Snails can retract their whole body inside their shell. Moreover, they are also able to retract their eyes and horns inside their body.
- Cats, with the exception of cheetahs, and some Civets have retractable claws.
- Some fossil evidence seems to imply early canids may have also had retractable claws.
- Toothed whales have retractable eyes.
- Goblin sharks have retractable mouths. They are able to extend their upper and lower jaws out of their head to give their bite extra reach.
- For Drag queens, part of the "tucking" process is securing their testicles into the inguinal canal, a recess in the hip bone.
- Retractable penises are very common in nature. Many mammals and reptiles have them.