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[[quoteright:350:[[Film/TheDayTheEarthStoodStill2008 http://static.tvtropes.org/pmwiki/pub/images/e5440d05b9479ff6e13ab8cde8b95afc.jpg]]]]

->''"Imagine you meet a magical leprechaun. For a bargain price, he offers to fix up your house and add an extra room. So you take him home, and he proceeds to eat your house and shit out a hundred and forty more leprechauns, which promptly murder you."''
-->-- '''Website/{{Cracked}}''' on [[http://www.cracked.com/article_16583_the-5-scientific-experiments-most-likely-to-end-world_p2.html Nanotechnology]]

Grey Goo is like a HordeOfAlienLocusts, only replace Alien Locusts with {{Nanotechnology}} or any other self-replicating material -- and instead of grass, they "eat" ''anything.'' Or, if the protagonists are lucky, just anything mineral or electronic.

They're worse than alien locusts. Grey Goo destroys resources by turning them into more grey goo -- more {{nano machines}} or whatever matter the grey goo is composed of. It's TheVirus for nonliving things -- though it may be able to take down living things as well, and likely will turn them into nonliving things if they're in the wrong place (ie: outside). In theory, you can end up with a planetary body made of nothing ''but'' grey goo. Physical laws regarding energy, thermodynamics and the like are an obstacle, but even a partial success in this case is likely to suck for everyone involved.

If you want to guarantee large scale destruction with free GreenAesop implications, make your goo specifically designed to clean up oil spills so that it has a built in taste for organic compounds, and is hard to kill.

Can cause TheEndOfTheWorldAsWeKnowIt -- specifically, Type 3a or 4 on ApocalypseHow.

Compare BlobMonster. For the RealTimeStrategy game about (and playing as!) the grey goo, see ''VideoGame/GreyGoo''.



* [[BrowserNarcotic How many tabs do you have open,]] [[WikiWalk and how many new tabs spawn from each of those tabs,]] [[TVTropesWillRuinYourLife and how much of your time have they devoured?]]

[[folder:Anime & Manga]]
* The titular creatures in ''Manga/{{BioMeat|Nectar}}''.
* Grey goo has completely devoured Mercury by the time of ''Manga/{{Gunnm}}'' (AKA ''Battle Angel Alita'').
* The ''WORMS'' in ''Anime/SkyGirls'' are related to this. Sort of.
* ''Franchise/{{Gundam}}''
** ''Anime/TurnAGundam'' features Black Goo in the form of the Moonlight Butterfly (''Gekkōchō''), which is named because it manifests as giant shimmering energy contrails that emerge from the titular HumongousMecha's back like wings. The nanomachines only target technology, but do so on an immense scale; the last time the Moonlight Butterfly was used, it sent humanity into a Dark Age that they're still recovering from (when the series begins, technology is roughly on par with the early 1900s).
** In Creator/YoshiyukiTomino's original novel, the ''full powered'' version of the eponymous Gundam can affect the area from Earth to Jupiter with the Moonlight Butterfly -- that's '''over 600 million miles'''.
** The DG Cells in ''Anime/MobileFighterGGundam'' are a combination of this and TheVirus, though strangely enough they were designed to be ''beneficial'', as their original purpose was breaking down dead or decaying matter and using it to foster new life. [[spoiler:The Devil Gundam instead uses them to reanimate dead humans under its control, or infect live humans and MindControl them.]]
** The G-Lucifer in ''Anime/GundamReconguistaInG'' (a series that takes place after ''Turn A Gundam'') [[spoiler:also has a Moonlight Butterfly system.]]
* The [[BigBad D-Reaper]] from ''Anime/DigimonTamers'' is a very slow form of Grey Goo, breaking down inorganic matter and reconfigure it into its various agents once it emerges in the real world. It's depicted as a mass of ''red'' goo in the series because its actually super-heated to extreme temperatures by accelerating its particles [[YouFailPhysicsForever beyond the speed of light]].

* What happened to [[spoiler:Negaduck]] after [[LiteralSplitPersonality being hit by the Tron-Splitter]] at the end of the ''ComicBook/DarkwingDuck'' story "Crisis On Infinite Darkwings".
* Adam Warren's adaptation of the ''ComicBook/DirtyPair'' revealed that the Earth had been destroyed decades earlier in a massive Grey Goo outbreak, the "Nanoclysm", which led to nanotechnology being regulated and virtually outlawed. The villain of the miniseries planned to use a cache of nanotech to take over HeroesRUs's Central Computer, and from there, the known universe. [[spoiler:Unfortunately, the Central Computer revealed that it was partially based on something the Nanoclysm left humanity as an apology…]] His later ''{{ComicBook/Empowered}}'' had a Grey Goo eruption that created {{Sexbot}}s, for reasons too complicated and silly to explain but which involved someone trying to use alien nanobots with an untranslated interface for perverse purposes.
* ''ComicBook/TheFilth'' features creatures like this, but portrays them in a very sympathetic light during the stages of their evolution. The more they spread, the more the world is seen from their perspective.
* The Modular Man from ''ComicBook/TomStrong'' is a hi-scale example of this. Each individual module is about the size of your head. Once he gets to Venus, though, he multiplies until he has something closer to the proper Grey Goo appearance.
* ''ComicBook/{{Transmetropolitan}}'' mentions it as a possible weapon if the commonly-used "makers" are reprogrammed. The standard MO for handling a "grey goo" scenario is to release "blue goo" (disassembler nanites that degrade matter -- all matter -- to the point where Grey G can't make more nanites out of it, and then destroy the Grey Goo nanites) to contain the grey goo and restrict its damage to a small area. One brief mention is made of someone who lost his legs because he decided to (and succeeded) shut off the grey goo instead of releasing the blue goo.
* One of the early comic issues of ''Magazine/{{MAD}}'' had the planet Mars consumed by the Gookum, a jelly-like pink substance which eats anything organic. It breaches TheGreatWall built to contain it, and, worse, ItCanThink. It stays dormant for 500 years at a time, and the joke/Mandatory Pulp Sci-Fi Twist is that cherry Jello parfait is completely indistinguishable from dormant Gookum. One day... one day the Gookum will quiver, will stir...
* One issue of ''ComicBook/FantasticFour'' claimed that the reason [[ReedRichardsIsUseless Reed has never tried to market]] the unstable molecules the team's suits are made out of is that if a careless person gets ahold of the stuff and pokes it the wrong way with an electron microscope, it starts destabilizing all surrounding matter into an ever-expanding blob of goo. Naturally in that issue [[BodyHorror someone careless got ahold of the stuff]].
* ''Comicbook/IronMan'''s Technovore is a nanotechnological entity driven to assimilate and integrate foreign technology into itself.
* In ''Comicbook/AtomicRobo'', Biomega (the setting's resident {{Kaiju}}) turn out to be a biological form of this. If left unchecked, they will eventually devour the Earth, then the solar system, the galaxy, other galaxies...


[[folder:Fan Works]]
* This is the final fate of Earth in ''FanFic/FriendshipIsOptimal''.
* In ''Fanfic/ProjectSunflower'', a meteor crashed into earth carrying a colony of alien nanomachines that consumes everything on the planet, forcing humanity to jumpstart the eponymous interdimensional portal project to find a new home.

* ''Film/TheDayTheEarthStoodStill2008'' tries to reboot the Earth with this. It was more a "Grey Cloud" than Goo, but same strategy.
* ''Film/GIJoeTheRiseOfCobra'' had "Red[=/=]Black" weaponized Goo (which is [[SicklyGreenGlow green for the viewer's convenience]]), which ate any metal it came into contact with. Thankfully, the designers were smart enough to build them with cutoff switches which neutralized them instantly. It also had a limited life span which meant that if its food source was too far away it would die out, depending on how much of a start it got. Eating the Eiffel Tower would give it enough of a start to devour all of Paris, but it would likely not reach another city. Devour [[spoiler: a single ship high in the stratosphere]] and it dies out long before it reaches anything else. It's unlikely that the nanomites were self-replicating at all. A self-replicating nanomachine is, by necessity, much more complex that a simple molecular disassembler. And if you're foresighted enough to build in a kill-switch, the very last thing you'd want to risk is the possibility of generational copying errors disabling that function.
* ''Film/TheBlob1958'': The monster ''could'' be either this or TheVirus. No one's really ever gotten close enough to examine it without being eaten. All that's known about it is that it's of alien origin. Oh, and it prefers to devour ''organic'' life as opposed to inorganic matter.
* ''Film/TheBlob1988'': The remake of the movie had the Blob be the spawn of a secret government germ warfare project. There it acted less like mindless spreading Grey Goo and more like a malicious, semi-intelligent monster.
* "The Lonesome Death Of Jordy Verrill" from ''Film/{{Creepshow}}'' features the opening phase of a Green Goo scenario, as Jordy and his farm are overgrown by the alien "weeds".
* [[spoiler:Ego's]] plan in ''Film/GuardiansOfTheGalaxyVol2'' involves this: he plans to make every planet in the universe an extension of him by way of implanting a device on each planet that, when activated, creates a giant blue blob that eats everything in its path. Although we don't see much of what it does besides "consume things", we can assume that it assimilates everything it touches into [[spoiler:Ego]].

* Ice-nine in ''Literature/CatsCradle'' turns any water it touches into more ice-nine.
* ''Century Rain'' by Creator/AlastairReynolds has Earth effectively uninhabitable from the effects of rogue swarms of nanobots. The nanobots were originally created to affect weather patterns, but they were corrupted. New bots were created to fight those, which went rogue, and so on and so forth. The survivors from the disaster, who now reside in orbital habitats, ''weaponized'' the Grey Goo and use it as a weapon of mass destruction. Something similar happens in his Literature/{{Revelation Space|Series}} universe, where [[spoiler: The Greenfly terraformers go rogue and will inevitably consume the entire universe.]]
* One of the best examples is Wil [=McCarthy=]'s ''Bloom'', a novel set in a future where the last fragments of humanity lives in habitats in the asteroid belt and in jovian orbit, after the entire inner solar system was devoured in a Grey Goo incident. Earth, Venus, and Mars are now large fuzzy balls of nanotech, nanotech solar sails drift aimlessly throughout the system, and occasionally errant strands drift out on the solar winds and try to devour anything they touch in the outer solar system. [[spoiler:It's okay, though, because the billions of people devoured in the incident are merely compressed, not gone, and their brain engrams still survive in the bloom, immortal and living in virtual paradises of their own construction; imagine how powerful a computer would be if it was made from an entire solar system?]]
* Another über-example would be Charles Stross' ''Literature/{{Accelerando}}'', where pretty much the same events as in ''Bloom'' happened ''deliberately, and for the betterment of mankind''.
* The novel ''How to Mutate and Take Over the World'' ends with [[spoiler:nanites from a dessert factory transforming the world into key lime pie. And this gets spoiled about a third of the way in, [[NoFourthWall in a fictional review of the book]]]].
* In one of the ''Literature/ThursdayNext'' novels, Thursday's time-traveling father tells her of a future wherein the world was overtaken by such a scenario; the world is consumed by pink slime. [[spoiler:It turns out to be strawberry pudding.]]
* ''Literature/DeathFromTheSkies'' by Phil Plait presents a berserker Von Neumann probe, which is essentially grey goo on a cosmic scale.
* In ''Literature/{{Prey}}'' by Artist/MichaelCrichton, the main plot is a Grey Goo experiment which has gone rogue and escaped containment. This one's ''slightly'' more innocuous in that it's partly biological and relies on ''E. coli'' bacteria to produce new nanobots rather than instantly dissolving anything it touches into more goo (it does seem to have some limited ability to "eat" silicon chips from integrated circuits). Of course, this really just means it needs to find a culture medium to grow ''E. coli'' in, and there are all these bags of moisture and nutrients wandering around...
* Neatly inverted in Charles Stross' ''Literature/SaturnsChildren''--robots think of organic life as "pink goo," reproducing without limit.
* In Scott Westerfeld's book ''[[Literature/{{Uglies}} Specials]]'', the main characters break out of a weapons storage facility using nanotechnology-based silver goo (much more flashy and dramatic than plain old gray goo, to paraphrase the author).
* A rather spooky example [[http://qntm.org/gorge presented here as a story]], [[spoiler:which shows us why you should just let the gray goo be...]]
** And played with in [[http://qntm.org/transit this story on the same site]], [[spoiler:where the sentient gray goo triggers the nanoapocalypse to ''save'' humanity from an impending asteroid collision.]]
* Charles Pellegrino and George Zebrowski's ''Literature/TheKillingStar'' includes weaponized Grey Goo which is used to [[spoiler:pick off one of the few surviving outposts of humanity.]]
* Creator/GregBear:
** In ''The Forge of God'', this is done deliberately and systematically by a belligerent alien race, to humanity as well as at least one other race. The sequel, ''Anvil of Stars'', is the story of a handful of the survivors of Earth -- specifically, the children -- seeking out the race that destroyed Earth, to enact [[EarthShatteringKaboom the Law]].
** In Greg's ''Literature/BloodMusic'', the Green Goo is not nanotechnology, but biotechnology, but operates in basically the same fashion. The "noocytes" consume all the biomass in North America, converting it to more noocytes. [[spoiler: It turns out that all the living creatures who are assimilated are also recorded and "alive" in a new kind of reality, similar to "Bloom" above.]]
* The Melding Plague also ended humanity's golden age in Creator/AlastairReynolds' ''Revelation Space'' series. Everybody was enjoying the benefits of a [[{{Magitek}} highly advanced nanoscience]], until humanity encountered a plague that could subvert all but the hardiest [[NanoTech nanotechnology]]. Such subversion has disastrous consequences for the device in question, anything to which it was attached, and potentially anything nearby. This is partly used to justify the somewhat SchizoTech nature of the setting.
* Played with in ''TheDervishHouse'' by Creator/IanMcDonald. The Grey Goo scenario is a common fear in the near-future setting due to a famous scientist's doomsday predictions of a nanotech catastrophe, even though it's generally accepted that he was just fearmongering and was wrong. A character later comments that the Grey Goo scenario ''has already happened''; it's called organic life. It turns out that [[spoiler:self-replicating nanotechnology is key to a massive terrorist attack, but not in the traditional sense]].
* In ''Literature/DeltoraQuest'', [[spoiler: the Shadow Lord has a literal grey goo flood set up as a final XanatosGambit.]] It was designed to [[spoiler: kill everything on the continent,]] but [[spoiler: the Shadow Lord didn't count on [[SpannerInTheWorks dragons]].]]
* In the ''Franchise/StarWars'' RPG supplement ''The Unknown Regions'', a Grey Goo named Mnggal-Mnggal is mentioned. It is sentient, and able to infect any form of matter, as well as take control of creatures as 'zombies'. Its origins are unknown, and it's likely biological. Note: If there was a trope for biological Grey Goo Mnggal-Mnggal would fit there.
* In Creator/JackMcDevitt's ''[[Literature/PriscillaHutchins Chindi]]'', an ancient alien satellite that has already mysteriously destroyed one ship is being much more carefully investigated by a second when the ship begins to come apart. It turns out that the satellite uses grey goo to repair/replicate itself, and the ship is being eaten. Several people die, and one, the artist with a big crush on Hutch, is rescued just in the nick of time.
* In Creator/JohnCWright's ''Literature/CountToTheEschaton'', the Savants used Golden Goo. It destroyed the cities, where it was released first -- killing most people there, with only a few stunned to be transferred with their minds intact -- and only by savage, fiery attack by the Giants was the earth saved from their "Golden Age."
* In Creator/WalterJonWilliams's ''Literature/{{Aristoi}}'', a form of grey goo (called "mataglap nano") destroyed EarthThatWas. As a result, only the eponymous Aristoi are legally allowed to use nanotech freely and they are fanatically paranoid about the possibility that any given form of nanotech could somehow mutate into mataglap.
* In the short story ''[[http://clarkesworldmagazine.com/mellor_09_13/ Mar Pacifico]]'' by Greg Mellor, nanotech designed to fight the effects of global warming (by letting the oceans absorb more carbon) sweeps over the Earth absorbing most forms of life. [[spoiler:When the protagonist is absorbed, she discovers that humanity still exists as a linked HiveMind inside the nanotech.]]
* In SA Swann's Literature/TerranConfederacy universe, the human colonies on Titan and the outer moons were devoured by a Grey Goo swarm, leading to Main/{{Nanomachines}} being made one of the Heretical Technologies. The Confederacy and its successor states continued this policy, enforcing it with things like [[ColonyDrop hundred kilometer asteroids]]. ItsTheOnlyWayToBeSure!
* Hal Duncan's ''Literature/TheBookOfAllHours'' has {{Magitek}} nanites charged with the souls of dead gods. It's an ideal medium for carving new identities on people's minds and souls by tattooing their bodies. A large collection also gets loose at the end of the first book, leading to a Grey Goo scenario that gnaws at the very substance of reality. All that's left are pockets of semi-stable time and [[TheoryOfNarrativeCausality narrative]] as spacetime [[TimeyWimeyBall gets even more fractured than it already was]].
* The title ExtremeOmnivore BlobMonster in the ''Literature/TheClone'' has some shades of this, although it's green and not grey. Nearly everything it touches, organic and ''in''organic, it converts directly into more of its own body mass.
* Discussed derisively in ''Literature/SchildsLadder'', which is set in a post-[[TheSingularity Singularity]] galactic society: an AI character mentions the conspiracy theory that [[TheMetaverse metaverse]]-dwelling minds would assimilate planets for computational resources, calling it as preposterous as accusing organic beings of plotting to turn the world into chocolate for infinite desserts.
* ''Literature/TheFourHorsemenUniverse'': The BountyHunter protagonist of the ShortStory "The Last Guardsman" is mortally wounded when his quarry wings him with a [[AbnormalAmmo grey goo bullet]] that eats him alive from the inside out.
* ''Literature/{{Aeon 14}}'': Nanotechnology is common in the series and nanotech weapons easily combated. However the picotechnology mastered by scientists aboard the colony ship ''Intrepid'' is potentially very dangerous: the Intrepid Space Force under Tanis Richards successfully uses picobombs several times against opposing ships, but there are reports of people trying to replicate the weapons and getting entire planetary civilizations eaten for their troubles (or killed by OrbitalBombardment when the Orion Guard gets wind of the experiments, in the case of the birth family of Tanis's adopted daughter Sanavi).

[[folder:Live-Action TV]]
* A failed pilot for a TV series called ''Doorways'' by Creator/GeorgeRRMartin featured a parallel dimension where, yep, nanomachines used to eat up oil spillages went and ate all the oil. This scenario was the result of ExecutiveMeddling -- G.R.R.M's original script (and the one found in his "Dreamsongs" retrospective compilation) featured the parallel Earth as a [[SingleBiomePlanet Winter World]], but this was apparently too bleak for a first episode.
* The Replicators of ''Series/StargateSG1'' are this trope scaled up to Lego size. When they eventually [[MechanicalEvolution evolved]] to silver goo, their diet changed from "any kind of metal" to "[[{{Unobtainium}} neutronium]] only", thus keeping the new model [[TooAwesomeToUse a rarity]].
* A minor example of this was the nanite colony Wesley Crusher was running in one episode of ''Series/StarTrekTheNextGeneration''. Fortunately, this goo turned sentient and was willing to be moved to a better food source before it disabled the ship.
* The villain Mantrid in the second season of ''{{Series/Lexx}}'' used Mantrid drones -- basically flying arms -- to systematically disassemble and convert all matter in the universe into more Mantrid drones. By the end of the season, nearly three-quarters of the universe had been converted, and the remainder would have been finished off within a few days. [[spoiler:Kai tricks Mantrid into flying the sum-total of his drones directly to the center of the universe, precipitating a Big Crunch which destroyed that universe but ejected the Lexx and crew into the next one over.]]
* In the ''Tales of Tomorrow'' episode "Red Dust", space explorers who've just visited a once-populated world overrun by Red Goo discover the pink crystalline "dust" has infested their ship, as well.
* In the ''Series/{{Stitchers}}'' episode "Two Deaths of Jamie B", the eponymous victim was trying to make nanobots to clean up oil spills and accidentally programmed them to recognize the wrong kind of organic molecules, so that they specifically target living things. Fortunately, he figures this out before they are released and shuts the project down. Unfortunately his boss is StupidEvil enough to want to restart it as a weapons project.

* The music video for "Nanobots" by ''Music/TheyMightBeGiants'' involves swarms of little yellow robots [[TurnedAgainstTheirMasters turning against their creators]] and taking over the world before turning it into one big yellow robot.

* The old ''Radio/LightsOut'' radio serial had "Chicken Heart", a biological grey goo that started out as a cell culture from [[ExactlyWhatItSaysOnTheTin a chicken heart]] and turned into some kind of mindlessly spreading cancer blob that quickly overwhelmed the research lab, university, and city that it was created in. Even worse, [[OnlySaneMan the researcher responsible]], escaping with a reporter in a plane, knows [[NukeEm exactly how to stop it]], but [[TheCassandra the authorities refuse.]] [[WeirdAlEffect Somewhat more famous]] is Creator/BillCosby's Jell-O-soaked retelling as he remembers hearing it on the radio as a kid.

[[folder:Tabletop Games]]
* Gray Goo is discussed in ''TabletopGame/{{GURPS}}: Ultra-Tech'' in a section on Von Neumann machines and points out the waste heat of the goo eating a planet is likely a more pressing threat than being eaten by it. On the up side they require extremely high level technology and are expensive to make, on the down side some versions might be able to fly or travel through space.
* ''Centauri Knights'', a far future/HumongousMecha sourcebook for ''TabletopGame/BigEyesSmallMouth'', takes place on a dead alien planet colonized by humans. According to the GameMaster information in the back, the reason the planet was vacant was because an ancient war resulted in a Grey Goo superweapon accidentally being unleashed upon the planet (the game even explicitly uses the term "Grey Goo" to explain the phenomenon).
* Virus Bombs of ''TabletopGame/{{Warhammer 40000}}'' work on a similar principle to the Red or Black Goo scenario noted above. They utilize something called the Life-Eater virus, which consumes everything organic on a planet and leaves behind massive, highly flammable swamps and gas clouds. A follow-up series of incendiary missiles ignites a planet-wide firestorm that scours any remaining life from the surface, leaving nothing behind but a glowing, lifeless rock. The Imperium uses them in dire situations when [[TheEndOfTheWorldAsWeKnowIt a problem can only be solved by destroying a planet]]. For added NightmareFuel, note that the Life-Eater is absolutely in the [[EldritchAbomination Chaos God]] [[{{Plaguemaster}} Nurgle's]] wheelhouse. Many of those who have the authority to use these world ending protocols have wisened up, and will prefer to use a [[EarthShatteringKaboom Cyclonic torpedo]] instead.
* ''TabletopGame/DungeonsAndDragons'' has this in the form of green slime, which converts anything it touches into more green slime. (Except stone, which is immune to it, and wood is more resistant than most. It dissolves metal ''very'' fast, however.) Fortunately, it's immobile, so you can avoid it if you just stay away from it.
* In ''TabletopGame/EclipsePhase'', Grey Goo swarms are among the nastier surprises left behind by the [[AIIsACrapshoot TITANs]]. There are various types ranging from regular roving disassembler swarms covering much of EarthThatWas to the rather more... ''artistic'' fractal bombs, which restructure matter into interesting fractal patterns as they spread (nobody is entirely sure ''why''. Presumably, their AI creators simply liked the look...). Their presence is basically the setting's primary GodzillaThreshold... if nanoswarms are involved, even the heroic factions will tend to break out the scorched-earth type weaponry, collateral damage be damned. And then there's "Creepers", swarms of floating black bubbles that are theorized to be ''femto''bots, if ordinary grey goo wasn't scary enough.
* DiscussedTrope in ''TabletopGame/{{Shadowrun}}''; Nanotech became very pervasive in 4th edition, and the Grey Goo concept is brought up, only written off as "unlikely to ever come to pass" and "an urban myth" by some of the (legit) top scientific experts in universe. Ultimately {{Averted}} as even when nanotech starts to fall prey to hostile A.I., it's shown that it isn't capable of destruction on anywhere near this scale, though it still proves to be ''very'' dangerous.
* The technophage in ''Nova Praxis'' is a Grey Goo substance that occasionally builds larger and meaner war robots instead of more goo. It started as a nanotech weapon with an off-switch that didn't work, and went on to [[EarthThatWas render Earth uninhabitable]].
* ''TabletopGame/{{Numenera}}'': At least one (and quite possibly several) of the ancient civilizations made extensive use of nanotechnology, and feral, out-of-control nanobots remain common and widespread in the setting's present.
** The Iron Wind is a natural disaster (insofar as anything in the setting is truly "natural") that takes the form of vast red sandstorms filled with microscopic, airborne nanites. These nanites are badly malfunctioning (the corebook outright refers to them as insane) and chaotically reshape anything and everything they come across, landscape, machine and creature alike. Living beings caught in the Iron Wind are reshaped into [[BodyHorror writhing, malformed monsters]] and usually die soon afterwards, if they aren't outright disassembled.
** Much more harmless nanites are also fairly well integrated into the ecosystem. They fill similar niches to organic fungi and bacteria, and generally go beneath most people's notice.

* ''VideoGame/TastyPlanet'' is a game based on Grey Goo where a cleaning agent gets bigger and bigger as you guide it through the levels starting on a Petri Dish until it eats the planet, then the solar system, galaxy, universe, space and time! [[spoiler:Then it explodes and everything starts over.]]
* The last "secret" life form class on ''VideoGame/SimEarth'', [[MechanicalLifeforms robots]] (unlocked by [[NukeEm bombing a Nanotech-class city]], fittingly enough), are very well-suited for survival. By this, it means that they reproduce rapidly, they can live in any habitat -- even the ocean -- and thus can spread across the entire map with little effort, competing against organic life [[CurbStompBattle can't even be called a competition]], and -- oh yeah. [[NighInvulnerability They're immune to disasters]], even ones activated by the player. [[AIIsACrapshoot All organic life on your planet will quickly go extinct when these guys show up]].
* The TrueFinalBoss of ''VideoGame/SuperRobotWarsOriginalGeneration'', [[spoiler: Septuagint]], can be seen as this. It may be more of [[spoiler: purple crystals]], but its directive is clear: exterminate the whole world by consuming anything to come to its path, and it can even make [[spoiler: crystal-based]] duplicates of things it has consumed.
* In the ''Franchise/MassEffect'' games, you can find a planet called Zaherux, which is covered with seas of silicon. The flavor text mentions that a popular extranet meme says that the oceans are actually a huge swarm of 'disassembler' nanites.
* Biological version in ''VideoGame/{{Outpost 2}}: Divided Destiny''. A terraforming microbe runs wildly out of control, breaking down organic matter, among other things, and forcing both colonies on the planet to try to evacuate-one of the rare versions in which the Goo truly is unstoppable, though one colony can delay it briefly, and the omnipresent threat during the campaign.
* In ''VideoGame/HostileWaters'', the "alien" antagonists have a Disassembler cannon which fires nanites that are programmed to rip apart matter on a subatomic level. This avoids the usual grey goo problem of endless replication, as the nanites just run out of steam, while still producing similar destruction. It fires at a city and reduces it to mush. It's up to you to blow up the cooling radiators before it fires its third salvo and destroys Central, the world capital. Once you do that, the next shot blows it to hell and spreads disassemblers throughout their base.
* In the [[http://www.youtube.com/watch?v=4_0ZzwptEUI intro cutscene]] of the video game ''VideoGame/DeusExInvisibleWar'', a terrorist employs a "Nanite detonator" in Chicago, [[DoomedHometown destroying the city]]. And in the first ''VideoGame/DeusEx'', the [[spoiler:Gray Death is revealed to be an artificial plague]].
** In Invisible War, there are also "nanite swells" -- clouds of nanobots whose origin isn't entirely clear, but which present a serious environmental hazard and are responsible for the poor health of people forced to live outside protected cities. It's never made entirely clear if these are actually self-replicating or just the remains of weapons or experiments used during TheEndOfTheWorldAsWeKnowIt.
* In ''VideoGame/SidMeiersAlphaCentauri'', one of the Special Projects shows the video of several containers placed on the site of a battle, littered with debris and dead bodies. The containers open, releasing nanites that look like glowing goo. They proceed to consume everything in sight, including the dead, and use the materials to create a brand-new HoverTank.
* Tiberium in the ''Franchise/CommandAndConquer'' universe can be seen a slow-acting example of it. It needs around half a century to engulf a significant portion of the Earth.
* Grey goo missiles called the "Nano Virus" are a high-level planetary siege weapon in ''VideoGame/SwordOfTheStars''. It is amusingly classified as a bio-weapon, meaning you have to go through several tiers worth of gene modification to access it. The Nano Virus is harmless to organics, but the planet's industrial output will be heavily damaged and it will wipe out an AI rebellion as if they were living creatures hit by a regular bio weapon. It is the only bio weapon that will affect the Zuul, since their machinery is made of the same metal as everyone else's.
* ''VideoGame/ParasiteEve'' features massive amounts of Pink Goo. The BigBad is actually a PatientZero infected with intelligent pink goo by accident. Every enemy in the game was created by the pink goo. If you go on to the Chrysler Building in the [[NewGamePlus EX game]], the building itself is infected with the pink goo (which is the in-world reasons that mode has random maps) and pink goo is literally everywhere.
* A grey goo like attack is possible in ''VideoGame/SupremeCommander2''. The Cybran Nation can upgrade their engineers to have weapons, by doing this and building nothing but engineers you will get an ever growing blob of engineers that will automatically shoot every enemy in sight and use the remains to build more engineers. [[http://www.pcgamer.com/2010/06/20/engineering-victory-in-supreme-commander-2/ Full instructions here]].
* In [[SuperSmoke Smoke's]] ending in ''VideoGame/MortalKombatArmageddon'', the power of [[ElementalEmbodiment Blaze]] causes his nanobots to go into overdrive, consuming all of Edenia and replacing it with a sentient mass of grey goo that calls itself Smoke.
* The Vasari from ''VideoGame/SinsOfASolarEmpire'', who specialize in Nanotechnology, have ships that are able to throw blobs of destructive nanobots at enemy ships.
* Provides the backstory and setting for ''VideoGame/{{Hawken}}''. In the endless CorporateWarfare on the planet Illal, one of the three dominant {{Mega Corp}}s collapsed, triggering a self-replicating nano virus that converts the environment into a labyrinth of patchwork metal--known as the "Giga Structure" and "Hawken Virus." At the time of the game's launch, the virus covered a third of the planet.
* The EldritchAbomination Deus from ''VideoGame/{{Xenogears}}'' is upgraded from a simple biological weapon into a living mass of Grey Goo by the game's BigBad Krelian through nanomachines.
* The RTS game ''VideoGame/GreyGoo'' has you-know-what as one of the factions. Apparently it was originally designed by humans to explore space, but its programming got corrupted somewhere and now it just attempts to consume all before it. [[spoiler: Though eventually it is revealed it is attempting to consume all before it for a reason and not just due to programming corruption -- it's a desperation move to build up an army against an attacking alien intelligence]].
* The Tarr in ''VideoGame/SlimeRancher'' are an organic example. They are formed when too many slimes eat too many plorts from other slimes and all they do is drag slimes and meat like the player and chickens and eat them. If they eat a slime they produce a copy of themselves.
* A possible story line from ''VideoGame/{{Duskers}}'' talks about the gray goo possibly wiping out life in the universe, or just within the Drone pilots area of operation.
* Part of the plot of ''VideoGame/MightyNo9''. [[spoiler:The FinalBoss, Trinity,]] was accidentally programmed to absorb everything it can, and it does. Which results in it absorbing nearly an entire building, transforming it into the game's cube-like equivalent of nanobots.
* The plot of ''Blam! Machine Head'' starts after a programmer at the world's biggest manufacturer attempts to inject himself with nanomachines to remodel his physic, causing the nanomachines to go airbornes and kill anything not matching his DNA.
* The same idea on a much larger scale happens in ''VideoGame/StarControl2''. The Slylandro, a planet-bound race, purchase a space exploration probe from some interstellar traders. They can afford only one, so they set its "replication" priority extremely high, causing it to attempt to break down everything it encounters into component compounds to build new probes. By the beginning of the game's timeline the quadrant is already swarming with these things, and it's projected that they'll continue to grow exponentially until they devour the galaxy unless you find a way to stop them.
* A variation of this occurred in ''VideoGame/HorizonZeroDawn'' - [[spoiler:a line of robotic soldiers that consumed biomass as fuel (supposed to only be in emergency situations) and could self-replicate was one day stricken with a glitch that made them ignore all commands and go rogue, and due to their highly advanced coding and the fact that the CEO of the company that created them [[LethallyStupid specifically told the engineers to not install a backdoor]], it was nigh-unstoppable and these rogue robotic soldiers consumed '''all organic life on the planet''' in less than two years. The title is derived from the in universe project meant to not only shut the rogue bots down, but to also bring life back to Earth through a highly advanced AI system.]]

* [[http://xkcd.com/865/ This]] page of ''Webcomic/{{xkcd}}'' jokes about how [=IPv6=] is perfect in that the nanobots will only be able to devour about half the planet before they run out of addresses.
** [[https://xkcd.com/1242/ Another comic on "Scary Names"]] noted "Grey Goo" might not sound scary, but is something as terrifying as "Bird flu" and [[https://en.wikipedia.org/wiki/Demon_core "Demon core"]].
* ''Webcomic/SchlockMercenary'':
** Hostile nanoswarms are so common that there's standard-issue tactics and equipment to stop them; people worried about nanobot infection drink nanotech-fighting chemicals to control them, "nanofilm" is routinely employed to control rogue nanobot swarms, and worst comes to worst, the nanobots will be isolated by ubiquitous AI with gravity-control technology. %%If anyone knows what the employer's name is, feel free to add it in. Go Go Wiki Magic!
--->'''Employer of the month:''' We've all been drinking Nanneze like it was Ovalquik.\\
'''Tagon:''' Careful, that stuff'll kill you.\\
'''Employer:''' What, the Nanneze, or the Ovalquik?\\
'''Tagon:''' ''Both.''
** The comic does point out one of the biggest weaknesses of nanobots: Extreme heat. Even when they have evolved plasma shielding, any reasonably dangerously level of heat will overwhelm any defenses the nanites have and cause their inner workings to warp and fail. If a gravitic-enabled AI isn't around to help, it's common to bust out the plasma weapons on wide spread to handle hostile swarms. For bonus points, most PowerArmor in the setting can handle fire without too much difficulty, so you don't even have to worry about your own men. Unarmored Civilians however can at best hope to get off with third degree burns to their entire body. [[GoodThingYouCanHeal Good thing medical technology has made a few advances...]]
** [[BlobMonster Sergeant Schlock]] has been mistaken for grey goo a [[http://www.schlockmercenary.com/2011-03-31 couple]] [[http://www.schlockmercenary.com/2015-06-12 times]]. And to be fair, they're not that far off.
* ''Webcomic/NobodyScores'': When all you have is a jar of nanorobots, [[http://nobodyscores.loosenutstudio.com/index.php?id=56 everything looks like a problem best solved by the application of nanorobots.]]

[[folder:Web Originals]]
* In the late 20th century of the ''Literature/ChaosTimeline'', nukes are scrapped because nanobots made them obsolete. The so-called [[GratuitousGerman Braunschleim scenario]] is the casual armageddon scenario everybody fears. [[spoiler:On the eve of WorldWarIII, this fear urges a bunch of {{Playful Hacker}}s to seize control over the military and the rest of the world, in order to prevent the danger of nano annihilation.]]
* In ''WebOriginal/OrionsArm'', humanity's exodus from [[EarthThatWas Old Earth]] was caused by the [[http://www.orionsarm.com/eg-article/4ad4d58752948 Nanodisaster]]. Interestingly, this is a case where the grey goo itself was quickly neutralized by blue goo (nanites created specifically to neutralize grey goo). [[HomeworldEvacuation The Great Expulsion]] was more due to the [[AIIsACrapshoot Global Artificial Intelligence Amalgamation]] created to protect Earth from human technological disasters by controlling said blue goo [[GoneHorriblyRight deciding to protect Earth from human technological disasters once and for all]]. The only choices were to live under strict ecological rules, get the hell off of [[FunWithAcronyms GAIA]]'s world, or face destruction.
* Website/SCPFoundation:
** [[http://scp-wiki.net/scp-204 SCP-204]] is a downplayed example, as the cloud of nanomachines usually only [[EatingMachine destroys animals (including living people) to serve as fuel]]. But SCP-204 is still ranked at the highest threat level possible, probably because from organic matter to anything else is a quick jump.
** [[http://www.scp-wiki.net/scp-3049 SCP-3049]] is a gas oven that creates a entire miniature universe inside itself. In most cases, one planet within this universe will develop sentient life that then creates nanotechnology, eventually leading to a Grey Goo event that transforms the entire universe into [[spoiler:an apple pie in a glass dish]].

[[folder:Western Animation]]
* In ''WesternAnimation/GodzillaTheSeries'', one of the first MonstersOfTheWeek is a colony of self-replicating petroleum-eating {{nanomachines}} that, inevitably, goes out of control and turns into a Zilla-sized shapeshifting blob on a feeding frenzy.
* An episode of the 1980's animated ''WesternAnimation/TheIncredibleHulk'' involved a scientist bioengineering a BlobMonster that could eat literally anything except the special glass of its container, and would get bigger the more it ate. Of ''course'' the glass breaks and it starts eating Gamma Base. ''Fortunately,'' it turns out that the one thing it's allergic to is gamma radiation, which the Hulk constantly emits.
* The ''[[WesternAnimation/JusticeLeague Justice League Unlimited]]'' episode "Dark Heart" dealt with alien nanomachines that were in the process of taking over Earth this way. Their species appears to be made artificially for a war from fifty-thousand years ago, and is meant to consume every planet they're sent to, spread to some other planets, and repeat until they're all dead.
* ''WesternAnimation/TheTransformers'' episode "Kremzeek!" involved a highly specialized electricity eating spark creature, splitting into new copies of itself as it ate more and more current.
** The "annoying replicating electrical prankster" story is actually a kids' show plot that really gets around. In the old ''WesternAnimation/{{Teenage Mutant Ninja Turtles|1987}}'' cartoon, it's called ''The Big Zipp Attack;'' in ''WesternAnimation/TheMightyDucks'' it's ''Zap Attack. WesternAnimation/{{Ben 10}}'' has the imagination to not name it after the creature: instead of something like ''"The Megawhatts Attack,"'' the critters are first encountered in ''Tourist Trap.'' (Unusually, the Megawhatts go on to be a seldom-seen but established part of the setting. They're actually an alien race called Nosedeenians, and make a return appearance in which Ben and company had to ''save'' them from villains who were kidnapping and enslaving them as a power source. It also turns out there's an Omnitrix transformation based on them as well; Ben calls this form Buzzshock.) It's not as obligatory as the FantasticVoyagePlot, but watch enough cartoons and you'll know it by heart.
* One episode of ''WesternAnimation/ThePowerpuffGirls'' features Grey Goo nanobots dropping from a raincloud and destroying Townsville, though the bots thankfully ignored living creatures.
* ''WesternAnimation/CodeLyoko''
** In the episode "Marabounta", Jeremie tried to create a virus that would destroy XANA's monsters, using [[BigGood Franz's Hopper's]] journal and basing it off African army ants. At first the huge blob-like monster seemed to work, attacking and devouring XANA's minions. Then something went wrong, and it tried to attack Aelita. Jeremie realized too late that her connection to XANA was causing it to mistake her for one of the monsters, but by then it was out of control and growing larger by the minute, threatening to consume all of Lyoko. (Leading to one of the most chilling scenes of the series to date, Yumi trying to protect Aelita, only to be devirtualized when she was EatenAlive by the thing.) Fortunately, XANA, who at that point needed Aelita alive to complete his plans, [[EnemyMine instructed his monsters to help the heroes]], and due to the brief alliance, they bought enough time for Jeremie to program an anti-virus that eradicated it.
** An earlier episode "Amnesia", had [[AIIsACrapshoot XANA]] infecting nanobots from a class as an infestation to cause massive amounts of memory loss.
* In the ''WesternAnimation/{{Gargoyles}}'' episode, "Walkabout," an artificially intelligent nanite mass begins a grey goo surge and the only way to stop it is to communicate with it in the Dreamtime. Once that was achieved, the mass was convinced to stop by interesting it in learning about human law and order and it bonded with Dingo's power armor for that purpose.
* Parodied in ''WesternAnimation/{{Futurama}}'' episode "[[Recap/FuturamaS6E17Benderama Benderama]]", thanks to an invention of the professor's that can make two half-sized duplicates of an object using consumed matter. Bender integrates the device into himself and starts making half-sized duplicates of himself by eating random objects. Each of the duplicates has the same ability. Eventually the replica-Benders become small enough to manipulate atoms directly and start consuming the planet's mass. Eventually, though, the quintillions of nano-Benders get fed up with doing work for Bender and leave the planet. At one point in the episode, Bender says the trope name word-for-word.
* In the ''WesternAnimation/MyLifeAsATeenageRobot'' episode "Party Machine", an army of tiny multiplying aliens invade Earth, which Jenny and Brad defeat with a vacuum cleaner-like tool created by Dr. Wakeman to defeat them.

[[folder:Real Life]]
* The scenario was first proposed by Eric Drexler. He has since dismissed it as unrealistic as it's much easier to create a bunch of tiny dumb robots that receive their instructions from a central computer (that can be disabled if it malfunctions) than it is to create tiny robots that know and are capable of doing everything they need to make copies. The dumb nanobots should serve any purpose we'd need smart nanobots for, so any grey goo scenario would have to be [[OmnicidalManiac created maliciously]].
** There's also the thought of police nanobots designed to keep the grey goo in check, a concept called "Blue Goo".
* Life itself has spread to every conceivable corner of the Earth (that we have been able to check so far) in the last 4.5 billion years and readily converts non-living matter into living matter through its inexorable reproduction. It is also really, ''really'' difficult to truly sterilize anything. This is sometimes referred to as the "green goo" scenario
** Hela cells (an immortal cancer cell line used in biomedical research) act like Grey Goo, in that they're notoriously hard to kill off and often [[http://hela-transfection.com/index.html contaminate and convert]] non-Hela cell lines. Hela is such a problem in many labs that, if the lab wants to use Hela, it cannot use any other cell line in fear of compromising good science. Incidentally, "Hela" is short for Henrietta Lacks, the name of the woman the cancer originally mutated from; this is ''human'' grey goo.
* A nuclear chain reaction could be considered a ''subatomic'' version of Grey Goo, in how it spreads from atom to atom, splitting each one so it ejects neutrons that split other atoms and thus perpetuate the process.
* Another, really freaky example from the world of nuclear physics is the [[https://en.wikipedia.org/wiki/Strangelet strangelet]], a particle of strange matter that's hypothesized to be able to convert normal matter into strange matter just by coming into contact with it. The converted particle then immediately does the same to a neighboring ordinary particle, and thus doom takes its course. If such a thing were to happen on Earth, it would quickly and irrevocably turn our pretty blue planet into an incredibly lethal ball of strange matter, and there's [[NightmareFuel nothing at all we could do about it]].
* Prionic brain diseases such as mad cow operate like Grey Goo for the nervous system, as abnormal proteins cause adjacent protein molecules to be reconfigured into more of the same.
* A more harmless, benevolent version of Gray Goo involves theoretical space exploration. It's believed that once we acquire the right technology, we'll be able to create interstellar probes out of nanobots. Once they land on a planet they'll convert as much matter needed into ten more nanobots and fire them out into space. However, others have speculated that such a system would devolve into a straight version of this trope given time (Carl Sagan argued that if they were viable this would already have happened); in fact swarms of so-called Von Neumann probes are an entire subgenre of this trope, including the deliberately malicious version often referred to as Berserkers.
* Another nuclear physics example (though slightly stretching the idea of grey goo): a true vacuum. If our universe is a metastable false vacuum, then at any time a true vacuum could spontaneously appear, and expand out at the speed of light. It would turn everything it envelopes into new forms of matter (and of course destroy everything in the process). Right now we can't rule this out, and perhaps a true vacuum is heading towards us right now...