[[quoteright:260:[[Film/TwentyEightWeeksLater http://static.tvtropes.org/pmwiki/pub/images/28weekslater-zombies_1433.png]]]]
[[caption-width-right:260:These guys? Not dead.]]

In quite a few modern ZombieApocalypse series (and occasionally works about other things that also incorporate EverythingsDeaderWithZombies), the creator ([[CaptainObvious obviously]]) wants to have zombies, but would rather not explicitly invoke the supernatural by having them be actual reanimated corpses.

This generally happens because it's somewhat more scientifically plausible - at least broadly speaking - that a plague turning infected people into crazed, flesh-rotten cannibals (or slow, lumbering cannibals) could exist in reality than that the dead could rise, so it gets past skeptics' WillingSuspensionOfDisbelief more easily. Or, as with many works featuring fast zombies, it may be used to justify why they don't act like the classic image of moaning, slowly shambling undead.

The virus responsible for zombification may be a mutated version of a real-life disease; rabies is popular because it already makes people and animals act, well, ''rabid'', as is mad cow disease (and prion diseases as a whole) because one major avenue of transmission is by eating infected brain tissue.

Since they ''are'' living people instead of animate corpses, these zombies are almost always easier to kill than the undead kind. They may disregard nonfatal (or not-immediately-fatal) wounds, but anything that would kill a human will kill them. It does run into a bit of a problem if you want a true ZombieApocalypse, since just like rabid animals they should die of starvation and/or dehydration fairly quickly; even more so if they're zombies that refuse to attack other zombies, refuse to eat dead meat, and will only attack and consume live humans, and aren't shown to seek out water sources. By the time a few weeks have passed, the original zombie infectees should be dead (in the permanent sense) as a lack of resources cause their bodies to fail. This trope is not recommended if you want Earth to be covered in zombies for longer than a month.

This is a subtrope of OurZombiesAreDifferent. It tends to appear alongside NotUsingTheZWord, but they aren't completely inseparable; zombies-in-all-but-name are often legitimately undead, and {{Technically Living Zombie}}s are often simply called zombies. The combination of the two has been known to start arguments among zombie fans over whether they're really zombies or not. Which naturally overlooks the fact that the popular, Romero-esque zombies are [[NewerThanTheyThink very different]] from traditional zombies too, which were basically entranced slaves of voodoo priests, and often very much alive.

This trope overlaps with particularly extreme {{Hate Plague}}s, but only if the plague causes its victims to act mindless as well as homicidally insane. Usually are a type 3 on the SlidingScaleOfUndeadRegeneration.

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!!Examples

[[foldercontrol]]

[[folder:Anime and Manga]]
* In ''BarefootGen'', after the bomb hits, many of the townspeople of Hiroshima that ''weren't'' vaporized became so badly [[BodyHorror burned]] (and probably disoriented), that they resembled ''melting'' zombies...except that they were still [[OhCrap (barely)]] [[AndIMustScream living]].
[[/folder]]

[[folder:Comics]]
* The ComicBook/{{Crossed}} are a twisted and nasty version of this.
* Bombie the Zombie from ''CarlBarks'' story "Voodoo Hoodoo" isn't an actual zombie. He's under a spell.
[[/folder]]

[[folder:Fan Works]]
* The newfoals from ''Fanfic/TheConversionBureauTheOtherSideOfTheSpectrum'' count. They are still living breathing beings, but inside, they're virtually dead as it's revealed that [[spoiler: when a human get ponified, their soul is literally shattered to pieces, and then [[GettingSmiliesPaintedOnYourSoul bound in chains]] to Queen Celestia's will. The only escape from this MindRape prison is [[MercyKill death]].]]
[[/folder]]

[[folder:Film]]
* ''Film/TwentyEightDaysLater'' (and its sequel, ''Film/TwentyEightWeeksLater'') has the Infected, which are living people driven insane by [[HatePlague the Rage Virus]]. The whole movie series is arguably the TropeCodifier.
** Notably, the Infected do die from starvation and dehydration in about a month, provided they're left alone.
** While they do use biting as a method of attack, The Infected are never known to actually devour their victim. Their aim is purely to kill, hence why starvation eventually catches up with them.
* The zombies of ''Film/{{Zombieland}}'' are actually suffering from a mutated version of mad cow disease. In one scene they can be seen feeding from a trash can, demonstrating that they still need food to stay alive.
* ''TheCrazies'' has a nerve agent airborne virus that turns people into oddly calm psychotics. It eventually either kills them or makes them kill themselves, but preferentially makes them target non-infected they have a grudge on.
** In the 2010 remake, the virus that causes the Crazies, is a modified and weaponized variant of rhabdoviridae, which Rabies is a part of that family of virii; that got into the water supply of Ogden Marsh. It was modified by the US Army at Fort Detrick, with the intention of destabilizing a target population, preferably the enemies'. It was on its way to an incinerator facility in Texas, before a storm caused the plane delivering the virus to its destination; to crash into the swamps around Ogden Marsh. It got into the watershed and ends up contaminating everyone.
* The zombies of the 1932 Creator/BelaLugosi film ''Film/WhiteZombie'' seem to be this: drugged living people rather than reanimated corpses.
* ''Film/{{Quarantine}}'' directly references rabies. (The original ''Film/{{REC}}'' looks like one of these as well, but ends up going [[DemonicPossession a completely different direction]].)
* The infected of ''Warning Sign'' become gravely ill and seemingly die, but are actually only going into a short coma before returning as murderous psychopaths.
* The zombies in ''[[Film/DeadAir2009 Dead Air]]'' are infected by a chemical agent spread by terrorists.
* ''The Grapes of Death (Les Raisins de la Mort)'' is similar to ''The Crazies'', with farm chemicals as the cause.
* ''Film/IDrinkYourBlood'' depicts an epidemic of rabies.
* The infected in ''Film/{{Carriers}}'' seem to act like zombies at various points. This is a strange breed because they only live a few weeks before the virus kills them and they maintain higher brain functions. When infected, many try to hide it and latch on to groups of survivors. They don't actively spread the disease, but do so through their infected breath. Most are interested only in themselves, but an infected doctor met near the beginning and a small infected child still have compassion for others (the girl for her immune father and the doctor for any survivors who manage to find him, he even goes as far to kill other infected that come to him).
* ''Film/TheSerpentAndTheRainbow'' uses the original, drugged-and-prematurely-buried voodoo (or at least HollywoodVoodoo) version.
* In ''Film/NightOfTheComet'', the "zombies" are humans brain-damaged and warped by partial exposure to the comet's radiations.
* The "zombies" of ''Teenage Zombies'' are just poor slobs who have been exposed to a gas that makes them act hypnotized.
[[/folder]]

[[folder:Literature]]
* Referenced as a background detail in ''[[HisDarkMaterials The Golden Compass.]]'' Apparently there's an African tribe which knows how to separate a human from their daemon ([[OurSoulsAreDifferent soul]]) without killing the human - just rendering them a mindless, corpse-seeming slave. And it's called a ''zombi.'' Much like in actual folklore. (This averts the "not supernatural" part of this trope, since this ''is'' supernatural from our point of view, and something like mad science in their universe. But, they're not biologically dead.)
** A troop of them show up in a later book; they are still living, breathing, intelligent humans, but lack a will of their own. They're also immune to the soul-eating Specters.
* The "vampires" in the proto-ZombieApocalypse novel ''Literature/IAmLegend'': the majority of infected people are still alive. Some of the vampires are actually undead, but when they infect a person, it turns them into a vampire without killing them.
** The film adaptation with WillSmith never uses the Z-word or the V-word, or even the word "undead". The infected (referred to simply as "darkseekers") are alive and is explicitly said to be by the protagonist, who is trying to find a cure for the plague. Apparently, it started with a cure for cancer based on the measles virus, but quickly mutated and became airborne. [[spoiler: It is later revealed that one of the antidotes that Neville was experimenting with was actually successful and the infected test subject was beginning to transform back into a normal human.]]
* The phoners in ''Literature/{{Cell}}'', who've had all higher brain function blasted away by the Pulse, at least until some new programming kicks in.....
* The Forged in the ''Literature/{{Farseer}}'' trilogy are a magic-based version of this, overlapping with TheSoulless.
* In ''Ashes'' by Ilsa J. Bick, the zombies, or "Changed", are teenagers hit with an electromagnetic pulse that killed most adults, but left them severely mentally impaired.
** In the second book, [[spoiler: it's revealed that the zombies are just as smart as humans are, but with a taste for human flesh. They can use weapons such as guns, can communicate with each other but cannot speak, and are intelligent enough to capture humans to eat later.]]
* Cranks from ''[[Literature/TheMazeRunner The Maze Runner Trilogy]]''.
* In the ''Literature/BlackTideRising'' series, those infected by the [[SyntheticPlague H7D3 virus]] are still alive in the biological sense, and can starve to death if left without food for sufficiently long time, but in the mental and emotional sense no longer really qualify as human.
* AbleTeam #8 "Army of Devils" involves a drug which turns gang punks into enraged killers, resulting loads of gorn, the use of excessive firepower and inarticulately growling attackers who need to be shot in the head to be stopped; it's been described by fans as a zombie story masquerading as an action adventure novel.
* The "Clayarks" of the ''Literature/{{Patternist}}'' series are this. The starship Clay's Ark returned to Earth carrying the disease that mutated humans into predatory creatures with heightened physical abilities and an instinctive compulsion to spread the virus. Eventually they [[ZombieApocalypse destroy civilization]], with only the [[PsychicPowers powerfully psychic]] [[MentalFusion "Patternists"]] able to preserve [[FeudalFuture feudal enclaves]] against constant Clayark attacks.
* Mira Grant's ''Literature/{{Parasitology}}'' series has these in the form of humans infected with a genetically engineered tapeworm that starts out as a health panacea but then GoesHorriblyWrong
* In the novel ''[[Literature/BloodBooks Blood Pact]]'', a MadScientist is reanimating the dead because, well, [[ForScience apparently there is a big push in the academic community to be the first to do so]].
[[/folder]]

[[folder:Live Action TV]]
* In the ''Franchise/StarTrek'' franchise, all the unnamed Borg drones behave in this way, despite being a part of a very intelligent HiveMind. Lacking free will or individual self-awareness, the drones' default goal is to [[TheVirus assimilate everything they come across into the collective]], though they'll ignore nonthreatening people walking around nearby if they have something more important to do. They're like zombies [-{{IN SPACE}}!-].
** In one episode of ''Series/StarTrekEnterprise'', the effects of trellium-D supposedly shuts down Vulcans' emotional control and turns them into paranoid killers. After exposure over many months, the crew Archer and co. meet are shambling around their ship with lumpy skin and mindlessly violent behavior.
* The Reavers in ''Series/{{Firefly}}'' are like this, though they retain enough intelligence to operate spacecraft, if not very safely.
* TheVirus in the Epidemiology episode of ''Series/{{Community}}'' gives people high fevers that make them act like zombies, complete with spreading via bites.
* On ''Series/{{Dollhouse}},'' mind-control technology is used to turn millions of people into mindless killing machines in the BadFuture. (And no, this future is ''not'' prevented.) This is one of the few types of zombism that isn't either supernatural ''or'' a pathogen, and it's not contiguous in any way. They are simply reprogrammed (via sound waves) people, and they can be reprogrammed back, or at least reprogrammed into something else.
* ''Series/{{Sliders}}'' had a zombie episode, when the people on a world being infected by mutated bacteria, originally designed to burn fat. Somehow, the infected also gained a sensitivity to light (they didn't burst into flames, but couldn't handle direct exposure to the sun). By the end of the episode, the protagonists manage to find a cure.
* ''Series/{{Warehouse 13}}'' had an episode focused on [[ArtifactCollectionAgency finding]] an [[AncientArtifact artifact]] that caused zombie-like symptoms in people.
* The "vectors" in ''Series/Helix". Super strong, super fast but alive and killable.
[[/folder]]

[[folder:Music]]
* Inspired by ''Film/TwentyEightDaysLater'' and ''VideoGame/Left4Dead'', the music video for "[[http://youtu.be/KQ6zr6kCPj8 Party Rock Anthem]]" by Music/{{LMFAO}} has music-crazed "shufflers."[[note]]''every day they're shufflin', shufflin'''[[/note]]
[[/folder]]

[[folder:Tabletop Games]]
* WarhammerFantasy has the Ghouls, who are cannibals from poor lands resorting to eating the corpses of the recently deceased because of their poverty. Whole packs of them gather around Strigoi vampires, who resemble them in both appearance and feeding habits. This was reflected in their rules, where they are considered to be "technically alive" and thus not bound to the army-wide rules that other units have (which includes both perks and handicaps, like not falling apart if the chief necromancer dies, but having to worry about morale). This was discarded for the sixth edition Vampire Counts army book in favor of streamlining the rules (them being subject to morale effects made them somewhat liable in the army, especially when zombies and skeletons are much better for this purpose), though in background terms they are still living creatures (albeit pallid and unhealthy ones), not animated corpses.
** TabletopGame/{{Warhammer 40000}} has the Pariahs, cybernetically modified humans put to use by the Necrons and their C'tan Masters. Like the Ghouls, they were unique in that they did not possess the Necron Rule. Unlike Ghouls, this was a liablity since it made them weaker than actual necrons (no regeneration) and would just plain disappear if the other necron units perished (meaning the enemy can completely ignore the Pariah, which wasn't hard to do since they were combat specialists with no movement modifiers). Less merciful than the Ghouls, they were completely retconned out of existence.
** An old White Dwarf had rules for running straightforward zombies in 40K, listing various forms, including some that were technically alive - people afflicted by Catachan brainleaf or Tyranid cortex leeches, or the victims of an Eldar device that ramped up life force until [[FateWorseThanDeath people with otherwise fatal injuries could be roaming, insane and violent but unable to die]].
* There are some variants of this sort in a few of the various worlds of ''AllFleshMustBeEaten''. Since zombies are there to be slaughtered in AFMBE, and these guys are technically human, the gamebooks including technically living zombies admit that some players might have an ethical problem with killing them, and suggest that the Zombie Master include ways to cure and save the zombies in this sort of situation.
* In ''MagicTheGathering'', there are Zendikar's nulls, which are basically vampire rejects (Zendikar's vampires are alive, not undead), while Innistrad's [[FleshGolem skaabs]] may or may not be undead, as their creation method is seemingly a life-inducing formula (and, accordingly, they are associated with Blue mana rather than the usual Black mana for zombies).
* 1st edition [[DungeonsAndDragons AD&D]] had "pseudo-undead": living humans who, due to congenital abnormalities, resemble some form of undead, zombies included.
[[/folder]]

[[folder:Video Games]]
* ''VideoGame/{{Fallout}}'''s ghouls are a somewhat different example from the usual strain, because (excluding the ferals, who act like typical zombies) they're basically regular people with a ''really'' bad skin condition and effective immortality. It's brought on by being exposed to a huge amount of radiation and not dying from it. And maybe a radiotrophic virus created by the military, depending on what version of the BackStory you believe.
** VideoGame/FalloutNewVegas brings us two new varients: Marked Men and Ghosts. Marked Men are almost-feral ghouls who inhabit [[{{Mordor}} the Divide]] who constantly have their skin flayed from their bodies but can't die due to the sheer radiation permeating the Divide. Ghosts are the previous inhabitants of the Sierra Madre who got caught in their hazmat suits while trying to protect themselves from the [[DeadlyGas Cloud]], with... [[BodyHorror limited success.]] Unlike the other quasi-zombies of the series, the Ghosts have a HealingFactor that will continually revive them unless decapitated, dismembered, or disintegrated.
** An aversion are the Lobotomites from ''Old World Blues'', who basically are cybernetically reanimated zombies, having had their brains (and then some) replaced with Tesla implants that allow them to perform basic motor functions and tasks.
* ''VideoGame/Left4Dead'''s Green Flu doesn't immediately kill its victims. According to promotional materials, it's a mutated strain of rabies. As its name suggests, in the game world it was designated a form of influenza by CEDA, though this was more of a cover-up than anything.
** The disease does prove to be eventually fatal, judging by the fact that a few zombies will collapse on their own. It's also said that children simply die instantly from the disease to explain [[HideYourChildren the absence of child zombies]].
*** Officially, the victims are called "Infected"; that doesn't stop everyone non-official from calling them zombies and [[GenreSavvy referencing zombie movie tropes]]. In-universe, the survivors referred to the infected as both zombies and infected.
* In ''VideoGame/{{STALKER}}'', areas are defended by '[[MindRape brain scorchers]]' which strip people of their higher brain functions, turning them into shambling zombies. ([[NotUsingTheZWord Yes, it actually calls them that.]])
* Darth Sion in ''VideoGame/KnightsOfTheOldRepublicIITheSithLords''. The only keeping him from death is the pain and hate within him, fueling the Dark Side of the force, and keeping his broken, scarred, decaying body from falling apart. [[spoiler: He eventually lets go of the force and dies, after being defeated by the Exile.]]
* Depending on whether the people taken over by the headcrabs are living {{Meat Puppet}}s or corpses, the headcrab zombies from ''VideoGame/HalfLife'' may or may not count. It's not made very clear, but evidence is in favor of them being alive; corpses probably wouldn't have the inclination to shout muffled but clearly agonized cries for help. Also, when you shoot them in the body, the body will fall down dead, but the headcrab will be perfectly fine, popping off to seek a new victim. Putting it all together does imply the body is still alive in some capacity, although how much intelligence or consciousness they have left is unknown. There's no known way to safely remove a headcrab without killing the body too.
* The [[VideoGame/ResidentEvil4 Ganados]] and [[VideoGame/ResidentEvil5 Majini]] in the latest ''Franchise/ResidentEvil'' games count, as they're infected with a parasite that takes control of the still-living host. The zombies of earlier in the series were suggested to be this, but the graveyard areas in ''[[VideoGame/ResidentEvil3Nemesis 3]]'' and ''[[VideoGame/ResidentEvilCodeVeronica Code: Veronica]]'' show that the T-Virus does in fact kill and then reanimate.
* Basic Redlight infectees ("Walkers") in ''VideoGame/{{Prototype}}'' are for all intents and purposes living zombies; except instead of being mindlessly driven by hunger, they are puppets for their "mother" [[HiveQueen Elizabeth Greene]], or other advanced infectees ("Runners").
* In ''VideoGame/PsiOpsTheMindgateConspiracy'' Jov Leonov's [[MindControl mind-controlled]] [[MeatPuppet Meat Puppets]] behave in a rather zombie-like manner, shambling mindlessly toward their enemies while ignoring injuries.
* ''RedDeadRedemption'''s ''[[RedDeadRedemption Undead Nightmare]]'' features both living and undead zombies. While the curse reanimated dead bodies, and being bitten by a zombie causes you to turn into one yourself, the process itself does not kill you. This becomes evident at the end of the game, when [[spoiler:Marston breaks the curse and the infected zombies revert to their old selves, while the undead ones merely drop dead again.]]
* In the final level of ''VideoGame/DeusExHumanRevolution'', you fight [[spoiler:crazies]] which move and attack like zombies. The zombie-like behavior is caused by [[spoiler:hallucinations from the vagus nerve being overstimulated by the biochips implanted in them, which is in turn caused by a signal released by Hugh Darrow in an attempt to show why human augmentation is bad]].
* The Zombies in ''Videogame/DeadIsland'' are the result of a mutated strain of Kuru (a real disease associated with cannibalism) and the game goes into fair detail about it. Unless you're one of the lucky few who's immune, getting scratched or bitten will infect and turn you within 72 hours.
** What's interesting about the zombies (though game mechanics are partially to blame for it) is that they cannot crawl on the ground. They're instinctively driven to stand up before they attack you. They don't instantly die from a headshot (though humans still do), and even though their blood coagulates and allows them to live with half their chest ripped off, they can still die of blood loss, puke up their own guts in response to poison, and even '''drown''' to death in water.
** Most people get turned into what are called "walkers", shambling zombies who are slow to respond to your presence. Some get turned into "Infected", who have no trouble sprinting towards you. The less fortunate are mutated with various degrees of BodyHorror. "Suiciders" bloat up with explosively deadly gas. They're still ''aware of what they are'', and moan "Help me" as they approach you, but they're instinctively designed to explode when they get too close to you.
** The worst seem to be the aptly named Butchers. These people are driven into what appears to be a chemically-induced rage, to the point that they've broke the bones in their own arms to fashion into shivs to carve into new victims.
* ''VideoGame/TheLastOfUs'' uses a mutated ''cordyceps'' fungus that takes over the brain. Notably, the developers have said that while the infected are a threat, the primary antagonists are [[HumansAreBastards other survivors.]]
* Husks in ''Franchise/MassEffect'', who are captured humans that were forcibly implanted with Reaper technology.
** ''VideoGame/MassEffect3'' features that the Reapers have created Banshees, Mauraders, Brutes and Ravagers out of huskified Asari, Turians, Krogan/Turian hybrids and Rachni respectively.
* ''VideoGame/MetalGearSolid4GunsOfThePatriots'' has a local-scale ZombieApocalypse when Ocelot attempts to disconnect his soldiers from the System that monitors and controls the emotions of all PMC soldiers in the area. The result is brain damage that causes them to mindlessly swarm you in packs, though "mindless" doesn't mean "emotionless" since, if you scan them with the Solid Eye, you can see their emotional states are spiking through the roof--unquenchable anger, hyper-hysterical mad happiness, bottomless sorrow and blinding terror; basically all the emotions their nanomachines were repressing suddenly being reintroduced and overwhelming them. There's even a use of "NotUsingTheZedWord" since Otacon calls the zombies "Those... things!"
* Parodied in ''KingdomOfLoathing'' with the "Modern Zmobie" (a "fast zombie"). One of its miss messages has you questioning whether it's actually a zmobie or just a human with a weird diet. [[CentipedesDilemma It gets too confused to attack you.]]
* Weepers from ''VideoGame/{{Dishonored}}'' are late-stage Plague victims, who are described as "Nothing more than moving corpses full of disease and insects." They are accompanied by swarms of flies, and attack by puking on Corvo. However, the game's KarmaMeter still counts them as people, so killing them is just as bad as killing a watchman, Overseer, or bystander, taking away from the GuiltFreeExterminationWar most games featuring zombies Invoke.
* In ''VideoGame/SaintsRowTheThird'', an aircraft containing volatile and dangerous chemicals crashes into one of the smaller islands making up Steelport, causing the lethal cargo to be released into the air and turn all the citizens there into zombies. The next mission has the player going there to deal with said cargo, and is slightly affected themselves due to a faulty gas mask, but once they get it patched up they're perfectly fine, and with said cargo pushed into the water the player can travel back there whenever they want with no ill effects (other than being attacked by the zombies, since they continue to infinitely respawn).
* ''VideoGame/WildStar'' has the Mordesh, a race of aliens plagued by a flesh-eating, insanity-causing disease christened the Contagion. They are still alive, and rely on Vitalus serum to keep from devolving into the usual flesh-eating Not Zombie. (By the way, they do not like being called "Space Zombies.")
* Corprus Stalkers in ''VideoGame/TheElderScrollsIIIMorrowind'' are shambling creatures with powerful regenerative abilities driven (usually, some rare examples are a bit more docile, and some just die instead) by the Corprus disease to attack non-infected people. Further progression of the disease turns the victims of Corprus into 'Lame Corprus', with more extensive physical [[BodyHorror mutation]]. This being a ''fantasy'' setting, said disease is explicitly supernatural (indicated to be ''divine'' in nature, even), and there are also actual (un)dead zombies around ([[NotUsingTheZWord not by that name in Morrowind]], but that's an in-universe naming quirk of the region the game takes place in).
[[/folder]]

[[folder:Web Comics]]
* The zombies of ''ZombieWaffe'' are infected with a new form of rabies which results in fast plague-zombies.
[[/folder]]

[[folder:Web Original]]
* The Zombies from WereAlive need to breath (homemade chloroform knocks them out), eat (they keep piles of flesh from humans and other zombies outside their "nest" at the Arena) and die from wounds other than [[BoomHeadshot headshots]] like shots to the chest or bleeding out from amputated limbs.
[[/folder]]

[[folder:Western Animation]]
* In ''SpongebobSquarepants'' many people who were bitten by Gary, though he had mad snail disease, and that it would turn them into zombies. But it turns out that [[spoiler:the mad snail disease was just a myth, and they just thought they were zombies because of what Patrick said.]]
* Smurfs bitten by the gnap fly turn [[http://smurfs.wikia.com/wiki/The_Purple_Smurfs purple]] and become mindless and aggressive. The condition can be spread to other smurfs by biting their tails.
* In one of TheSimpsons Treehouse of Horror special which parodied 28 Days Later, a zombie outbreak started when Krusty made a new burger which was made from a cow that cannibalized another cow. Kent Brockman took a bite out of one and instantly turned into a "muncher", and bit Krusty who started biting other people, soon almost everyone in Springfield were turned into munchers.
[[/folder]]

[[folder:Real Life]]
* In RealLife, rabies can cause zombie-like behaviour because of the brain damage inflicted by the disease. However, it doesn't incubate quickly enough or spread readily enough to cause a ZombieApocalypse, and the symptoms are somewhat different (most obviously, it doesn't cause the victim's flesh to rot). Also, humans rarely bite each other, even when brain damaged, so human-to-human transmission is largely unknown outside of a few cases of infected organ transplants.
** On top of THAT, there is a vaccine, which is always readily available to those bitten. You can even get it before you get bitten, such as if you are a veterinarian, a spelunker, or are going to an area where there will be many wild animals.
* One version of African zombie legends operates this way: living people can be turned into zombies using certain substances. It's commonly believed that tetrodotoxin is used to induce a state of paralysis [[FauxDeath that resembles death]], after which the victim's relatives bury them and the responsible sorcerer digs them up as the toxin is wearing off and slips them a hallucinogenic to make them think they are mindless walking corpses.
* Parasitic fungi in the genus ''Cordyceps'' will alter the behavior of the host insect in order to facilitate its own spread. In ants, this behavior is so alarming that any individual exhibiting it is carried very far away from the colony and left to die.
** Cordyceps isn't alone in nature, there are ''lots'' of parasites out there that are capable of modifying their host's behavior. And it's not just limited to other animals, some studies have suggested that [[http://en.wikipedia.org/wiki/Toxoplasmosis#Possible_link_to_psychiatric_disorders Toxoplasmosis]] can cause psychiatric changes in ''humans'' that are infected. Granted, it doesn't create zombie-like behavior, but it is certainly possible that there's an organism out there that ''can''.
*** Namely, the parasite ''Toxoplasma Gondii'' - a parasite mainly found in cats and mice - has been observed in rats to make them seek out places that reek of cat urine, instead of avoiding it like a normal rat. Studies on humans have so far implied that humans infected with it have slower reaction times, and that it possibly can "be a causative or contributory factor in various psychiatric disorders such as depression, anxiety and schizophrenia."
* Rob Zombie is technically alive (and in a possible subversion to the standard cannibalistic tendencies, he is an ardent vegetarian).
** Also, Mark Callaway, a.k.a. TheUndertaker; in a case of LifeImitatesArt, as he's aged and changed his style and exercise (not to mention injuries) he's gone from bulky and wearing makeup, to wiry and downright creepy looking. Sumbitch even said it in a recent promo spot: "I may look like the walking dead, but trust me, I am still very much alive!"
* On a chemical as opposed to biological vector, the news has (as of 2012) been awash with reports of zombie-like behaviour from the users of a drug colloqially known as 'bath salts' - to the point that one user was shot by police while in the middle of feasting on a homeless man.
** Subverted as the suspect in question was already crazy and it was determined that 'bath salts' had nothing to do with the crime.
* It's possible that zombie tropes may be partially rooted in events during TheBlackDeath or similar [[ThePlague plagues]]. Mass graves were used at times, and high fevers can cause delirium or even brain damage. So if someone was buried haphazardly but recovered from the plague enough to free themselves, witnesses would see an inarticulate, clumsy person covered with sores leaving a graveyard, which would look a lot like a "zombie" even when the [[UnbuiltTrope trope was unbuilt]].
** There may have even been plague victims supposedly "attacking" random people, uninfected or not, though this is all likely due to severe hallucinations and clumsy walking. And of course, no plague infected people would actually eat people they came in contact with.
* The disease known in Papua New Guinea as [[http://en.wikipedia.org/wiki/Kuru_%28disease%29 kuru]]. Like mad cow disease, it is caused by a prion (a misfolded protein that causes all sorts of damage). Victims lose their mental capacity, and the disease is characterized chiefly by confusion, malaise, and ataxia. People primarily contracted the disease when they ate deceased members of their tribes as part of their funerary rites.

[[/folder]]

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