You can't find it. It's gone. So, you forget about it. And then one day you get lost at sea, you wander too deep into the woods, your starship's hyperspace thingy malfunctions, or you just fall through a metaphorical crack in the sidewalk, and you end up discovering where all those missing socks go.
Charles Fort called it the Super-Sargasso Sea; the dimension into which lost things go. Amelia Earhart's over at the bar. The Lost Colony of Roanoke is next door. USS Cyclops? In the harbor. Elvis Presley? Who do you think is on stage? The Dead Sea Scrolls? Have a pamphlet. And everybody has all the socks they could possibly need. Just not matched ones.
This is a place everyone who's ever lost anything wished they could visit and that all treasure-hunters dream about; the multiverse's biggest attic/basement/toolshed. Everything is here. Starships, Ancient Artifacts, misfit toys. It's a Portal Crossroad World where it's easy to enter but significantly harder to leave. It's a Derelict Graveyard that people actually live in. It's a Landfill Beyond the Stars where the crap never stops gathering. It's everything you could possibly want mixed with all the stuff you hoped you'd never see again.
Appearance-wise, the places usually take the form of great spaces filled with endless mountains of haphazardly piled junk. More specialized examples may take more specific forms — a relatively common variant focuses on drawing in everything lost at sea, and typically resembles a stretch of the ocean filled with shipwrecks, flotsam, seaweed, and assorted nautical garbage. Characters who come to these places often do so in the hope of tracking down something specific or scavenging for useful, precious or interesting things; doing so, however, will typically require sorting and often digging through a much vaster quantity of worthless dross.
It tends to be fairly easy to end up here — although it may not always be easy to get here on purpose. There are generally any number of connections between the Super-Sargasso Sea and regular reality — you may get here through a portal, by being shipwrecked and cast adrift in an unusual patch of sea, by a malfunction in faster-than-light travel, teleportation or other method of transdimensional travel, or just by getting very, very lost yourself. Getting out, however, is usually a lot more difficult.
Often accessible via The Bermuda Triangle.
- Oblivion Island: Haruka and the Magic Mirror: Oblivion Island is where neglected objects from our world end up being used by the inhabitants who can't make them themselves.
- Sargasso appears in Yu-Gi-Oh! ZEXAL, after the heroes obtain a ship capable of traveling between the dimensions. They are forcibly sent there for an encounter with the Barians.
- Midnight Nation is a place of the lost and abandoned — not just objects but people. A particularly interesting element of that is a shack containing the lost work of every artist who died before creating it, kept safe until such time that another artist can create it.
- Wonder Woman: Several iterations of Paradise Island/Themyscira treat it as a place full of lost knowledge, magic and art where lost women fleeing violence end up. The original Vol 1 Paradise Island had some elements of this with the population being made up of refugees from across time and later writers ran with the idea in Vol 2, with even lost extraterrestrials ending up Amazons for a time.
- Daring Do and the Journey to the Center of the Earth has the Temple of the Lost. The protagonists go there to find Pinkie Pie's missing body, and they have to sort through loose change, missing socks, and other assorted junk first.
- The Adventures of Elmo in Grouchland: Grouchland is a world full of garbage and trash. In main villain Huxley's Villain Song "Make It Mine", he heavily implies that it is where missing items go to, and he subsequently takes them for his collection.
When umbrellas disappearThey're not lost. They're all herewith the keys you cannot find,Pens and mittens left behind,Got 'em locked in a boxwith a million missing socks.An army guy, a glove.Here it is. Oh, how I loveto make it mine!
- Halloweentown II: Kalabar's Revenge reveals that anything misplaced in either Halloweentown or the mortal world ends up at the house of Gort the ogre. If you lose an object while you are already at Gort's house, it is gone forever.
- Thor: Ragnarok: Sakaar serves as a sort of universal sinkhole, attracting a universe's worth of cast-off detritus to itself. Performing a Blind Jump will add you to the endless stream of junk falling from the myriad portals hovering above this Landfill Beyond the Stars.
- In The Familiar of Zero, lost objects and people from Earth often end up in the alternate world of Halkeginia. Earth technology is highly prized due to the world's low technology level.
- Finders Keepers: The protagonist visits the world where things go when you put them down a moment ago and can't find them again.
- Charles Fort (a writer on anomalous phenomena) apparently first created this idea when he speculated various curious missing persons cases and lost objects might have ended up here.
- Harry Potter has a variant in the form of the Room of Requirement. The room is enchanted to always appear in the form that someone walking past its hidden entrance needs it to have. Generations of Hogwarts students and staff needing somewhere to hide random crap has caused one of its many forms to be "a room the size of a large cathedral" filled with everything that's been hidden and forgotten over the centuries—though in the final book, it all gets destroyed with a good dose of wizard napalm.
- The Keys to the Kingdom: The Border Sea is full of lost object from the secondary realms.
- Mary Poppins and the House Next Door has Mary Poppins take the Banks children to visit her uncle, the Man in the Moon, who hoards physical items lost on Earth.
- "Ogon diabła" ("The Devil's Tail"), a short story by Janusz Zajdel, involves a researcher who discovers a dimension where lost items go to. And its inhabitants. The title itself is derived from a Polish folk saying which refers to lost items as "covered by the Devil with his tail".
- Pact: The many manifestations of the Abyss are places where forgotten things go, even gods forgotten by their former worshipers, and where Others such as bogeyman are formed.
- Pale, set in the same universe as Pact, introduces the Paths, which are home to things that have even been forgotten by the Abyss, including Others that predate the Seal of Solomon. Paths are accessed by practitioners known as Finders on an individual basis using nonsensical rituals like stuffing a doorframe full of red tickets and kicking it in, or surrounding yourself with a toy train set while repeating "hustle and bustle and hustle..."
- A Place Called Here: "Here" is the prosaic name for the place where lost things go, including a community formed by missing and disappeared people who have become stranded Here. The main character winds up in Here herself while working on a missing person report, and as the story progresses things begin to disappear from Here as well — a process that the locals find extremely unsettling, as by definition nothing ever goes missing from Here.
- Un Lun Dun is set in a city where lost objects from London go. Other cities have their own Super Sargasso Seas.
- Orlando Furioso places this on the moon. Orlando goes there to find his wits (lost because of a love potion).
- Charmed (1998): "Wrestling with Demons" has the Halliwell sisters using a spell to find lost things backfiring to the point that everything they ever lost came back, thus turning their house into this trope. It starts off fairly normal, returning lost jewelry and countless missing socks, but quickly runs to the ridiculous when their grandmother's dog who went missing years before turns up out of nowhere and Phoebe's blonde hair, dyed in the kitchen sink, suddenly reverts back to brunette.
Phoebe: So, technically, I lost it here and now I've found it again. [Beat] I hope this doesn't affect my virginity.
- Eerie, Indiana: The Land of Lost Objects is located at the center of the Earth and is run by the US government that steals objects to promote consumerism.
- The Twilight Zone (1985): In "Wong's Lost and Found Emporium", The Little Shop That Wasn't There Yesterday contains lost hopes, dreams, chances and attributes that people seek to regain. David Wong is searching for his compassion, Melinda for her sense of humor, Mrs. Whitford for lost time and the elderly man for the respect of his children. Each lost attribute appears in a glowing ball, which everyone except the intended recipient can see, and takes the form of a physical object or animal. The recipients must follow the instructions on the label to benefit from it.
- An episode of The Zack Files sees the title character stumble upon a dimension in the back of his dryer where all the lost socks end up.
- In Ben Lear's Lillian: A Folk Opera, the narrator believes that everything lost winds up eventually in the Great Pacific garbage patch. He journeys there to find a vague something that he thinks is missing from his romantic relationship.
- This trope is mentioned by name in the song Touch-Tone Telephone by Lemon Demon:
- And like you, I'm a genius before my time
Disbelieving, that's the real crime
Pretty soon they'll discover me in the Super-Sargasso Sea
- Dreadfleet: The game is set in the Galleon's Graveyard, a realm to which all shipwrecks and the bodies of those who die in the sea are magically drawn to. The Graveyard itself is a great maelstrom choked with millennia's worth of wrecked ships of every kind and the bodies of countless sea monsters, and is ruled over by a vampire and by the undead legions he has raised from the countless corpses drawn into his realm.
- Dungeons & Dragons: In (BECMI) module IM3 "The Best of Intentions", one of the planes the Immortal PCs may have to travel to is Unsoncy. The center of the plane is a rotating disk of debris that comes out of a singularity in the middle. Items lost on other planes of the universe end up here. The Immortal who controls the plane always looks here first when he loses a pair of socks in his washing machine.
- Pathfinder: Stormholt is a demiplane composed of an endlessly storm-tossed stretch of ocean filled with floating shipwrecks. It's closely connected to the treacherous harbor around the city of Absalom, and every vessel that sinks there has a chance to be pulled into the hungry demiplane. This is generally the only way to enter it — and leaving is a lot harder.
- Dark Void: The Void is a dimension where things are drawn to and trapped in from the Earth. Aliens, lost ships, Nikola Tesla. It's all in the Void. The hero even enters via The Bermuda Triangle.
- Submachine: This is how the titular Submachine behaves, with its architecture being comprised of a mishmash of ancient ruins from multiple civilizations.
- In Touhou Project, the barrier surrounding Gensokyo works such that it attracts things or concepts which have "become fantasy" in the outside world. While it's mainly a justification for the existence of youkai, it also attracts other things like extinct or endangered species, and yes, a bunch of lost items from the outside.
- This comes up early on in Real Life Comics when Mae tries to find her tape deck converter in the back of her Volvo. The resultant lost space includes Jim Morrison, Elvis Presley, Jimmy Hoffa, and Tupac, as well as quite a selection of lost socks. (And all the t-shirts, blue vests and shorts you could want.)
- One of the joke SCPs is the lost sock room.
- Bounty Hamster: On the search for Cassie's missing dad, Marion and Cassie find themselves in the world of the lost. Not only are lost objects there, but people too: there's a room of lost dads and even the antagonists that the duo 'lost.'
- Jacob Two-Two: A sock-oriented variant appears in one episode. Jacob finds an Alternate Dimension where all the missing socks go. Here, they use socks as currency, and there's even a black market for them.
- The 1943 animated short The Land Of The Lost features two children who, with the help of a magic talking fish, find an undersea realm where all things lost at sea end up, gain sentience, and live in harmony. There the boy finds his old jackknife, who he helps become a knight as thanks for being a trusty tool.
- In Peter Pan & the Pirates both the Lost Boys and the Pirates enter a group of caverns in Neverland that is indeed the Land of Lost Objects, where they even met Captain Hook's lost childhood.
- The Real Ghostbusters: The Land of Lost Objects is an extra-dimensional realm lost objects wind up.
- The Ren & Stimpy Show: In "Black Hole", Commander Hoek and Cadet Stimpy go through a black hole and end up in a strange dimension, where they find a pile of all of Earth's missing left socks.
- SpongeBob SquarePants: In "Welcome to the Bikini Bottom Triangle", the titular location contains many items taken by the mermaids via singing to activate a giant vacuum, which opens a rift in the sky while doing so. When they sing their song backwards, the items are returned to their owner.