When a character is believed to be dead for one reason or another only to reveal themselves to be alive and well, this goes in one of three ways. Either they are relieved that they are not dead, angry that they had to mourn them over nothing or (in a world of idiots or crazy people) everyone takes the Arkham's Razor approach and assume that they came back from the dead and intend to crack open their skulls and partake the gooey contents within. Vengeful Ghosts, ghouls, zombies, werewolves (if they looked like they were mauled half to death), Stringy-Haired Ghost Girls, any supernatural affliction to the body is acceptable.
It is especially bad when a Zombie Apocalypse is going around, so convincing your fellow survivors that you're alive without getting a bean-sized hunk of lead through your kidneys is much harder to sell.
Compare to Actually Not a Vampire, Mistaken for Aliens, Mistaken for Dying, Mistaken for Superpowered and Reports of My Death Were Greatly Exaggerated. Contrast with Technically Living Zombie and Not a Zombie. An inversion of Mistaken for Afterlife. See also Mistaken for Murderer, Mistaken for Own Murderer, Not Using the "Z" Word and Totally Not a Werewolf.
- In the My Hero Academia OVA "Training of the Dead", a student from a different school brought in for a training exercise has a Quirk that turns most of Class 1-A into zombies. All Might jumps in to save the day, only to run out of time and return to his emaciated form. Ochako and Mina confuse him for a zombified civilian and run away (dragging Midoriya and Todoroki along with them), and when the zombies surround him... one pats All Might on his shoulder reassuringly, having confused him for one of them as well.
- During One Piece's Thriller Bark arc, right after Luffy mistakes a zombie for a wounded old man, his crew run into a wounded old man that they mistake for a zombie.
- In Pokémon, the episode "Pokemon Shipwreck" had Ash's gang and Team Rocket working together to escape the sunken ship. Ash's friends all use water Pokemon to escape, while Team Rocket uses James' useless Magikarp and nearly drown. When Team Rocket wash up unconscious, Ash and co. believe they have drowned and are about to give them a water burial. However Team Rocket awakens and are angry at almost being pushed in the water, while Ash and friends scream out "ZOMBIES!"
James: Who are you calling zombies?!
Jessie: We are not zombies!
- Happens a lot in Alpha Girl: in a world where many women have become zombiesnote , male characters usually ask whether a woman is a zombie or not... or just straightforwardly kill or capture them without confirmation. The Protagonist Judith, who is not a zombie, suffers from this regularly.
- Played with in Futurama comic: Professor Farnsworth meets his old crew who he thought had died in a vortex but really they survived. He thinks they're zombies but they confirm they are not. However, it turns out that three of them (Sheila, Sly, and Dr. Zoidberg the Second) were killed afterwards and replaced by holograms. Mender the robot, however, is real; in fact he's the one who killed them.
- In The Walking Dead comics (as well in the TV adaptation), the survivor protagonists sometimes disguise themselves as walkers (wearing their clothes and even covering themselves with blood and skin) in order to walk unnoticed among them. This later goes Up to Eleven with the "Whisperers", a nomadic group of survivors who are disguised as walkers all the time.
- In Zombies en la Moneda, El Kila, one of the protagonists, meets a group of Chilean neo-Nazis. When they see that he is covered in blood (someone else's blood), they believe he is infected and will become a zombie, so they attack him. At that moment a military patrol sees them, mistakes the neo-Nazis for zombies, and ends up killing them all and saving El Kila.
- In the House fanfic "Iggy Pop Go The Zombies" (the House cast in Shaun of the Dead, basically) Wilson panics and mistakes Thirteen for a zombie.
- My Huntsman Academia
- In the sidestory "Ghostly Activity", Ruby is snooping around late at night while trying to figure out who keeps raiding her hidden cookie stash. She ends up poking her head into a dark room and sees a vaguely humanoid figure that glowed gold and was staring directly at her with neon green eyes. She ends up bolting right there. It turns out that Izuku was just meditating and practicing with One For All.
- In "A Nightmare Before Solstice", Pyrrha is woken up by the sound of movement in the dead of night while a fierce snowstorm was raging outside. When she goes to investigate, she encounters a skeletal figure with nearly translucent skin, loose, flabby coverings, and coughed up blood. She quickly runs off screaming into the night. It turns out it was just Toshinori who had just come back from a long night of heroing.
- When Astrid walks in the great hall in Prodigal Son after everyone believed her to be dead via shipwreck, Snotlout is quick to point to her and call her a draugr.
- In Hot Bot, Huffy and Nard accidentally run down the Sexbot Bardot with their car. Because she looks and feels human but has no life signs, they assume they have killed her and take her back to Huffy's house to conceal her while they work out how to dispose of the body. When she reboots and gets up, they assume she is a zombie and Nard fetches a chainsaw to attempt to dispatch her.
- In the Harold Lloyd comedy Hot Water, the main character believes that he's accidentally killed his mother-in-law. When she starts Sleepwalking, he thinks it's her ghost.
- Invoked in Muppet Treasure Island: Long John Silver sets Captain Smollett's First Mate Mr Arrow adrift in a leaking lifeboat and tells the rest of the crew he drowned, then leads them in a mutiny against Smollett. When Mr Arrow returns, the members of the crew who stayed loyal to Smollett cover him in seaweed and make him pretend to be his own Vengeful Ghost, terrifying the mutineers into fleeing Smollett's ship without a fight.
- In Zombieland, it is revealed that Bill Murray has survived the Zombie Apocalypse by using his skills at acting and make-up to make himself look like a zombie, allowing himself to thrive in Hollywood unmolested by Flesh-Eating Zombies. Unfortunately it works a little too well, since he gets heavily bruised by Tallahassee and Wichita when he walks in on them and then later fatally shot by Columbus.
- In the Acts of the Apostles in The Bible, an angel miraculously rescues Peter from prison the night before he's supposed to be executed. Peter goes to a house where the church is gathered praying for him, but amusingly they don't believe at first that it's really him, saying "It must be his angel!"
- In Desperaux, the eponymous mouse is thought to be dead by his parents, so when he comes back, his mother points to him and shouts, "A ghost!".
- In a Doctor Who Expanded Universe story, "The Somerton Fetch", the Third Doctor follows the trail of a crude time machine. He eventually discovers its pilot is a young girl, and after an incident with a maid in the past, he concludes the girl's primitive Perception Filter costume malfunctioned. The Doctor and the girl materialize several times, intangible to the world around them, until he manages to send her home. He returns to the present to find the girl's suit was working correctly — all those people running away screaming their heads off were doing so at the sight of the Doctor, who's become enshrined in local folklore as the eponymous ghost.
- Subverted in the Just book "Just Tricking" in the story "Playing Dead". Andy plays dead to get out of going to school and doing a test he didn't study for, and his parents act like they're going to bury him. When he reveals that he's alive, his mother acts like she thinks he's a zombie, but it's revealed that she's only kidding and both of them knew all along that he was alive.
- In the Lockwood & Co. book The Creeping Shadow, Quill Kipps tries out a pair of goggles that allow adults to see ghosts and mistakes the elderly Reverend Skinner for one.
- The Amazing Stories episode "Mummy Daddy" is about one poor actor being trapped in his restrictive mummy costume and being chased by a band of murderous redneck hicks.
- The Rise of Phoenixes: Noble Consort Chang sees what she thinks is Ya Le's ghost. It's actually Zhi Wei pretending to be Ya Le's ghost.
- Scrubs: After having spent the most of the day trying to get away from work after Dr Cox pettily has him pulled from his day off, in revenge for his days as an intern, JD attempts to leave the hospital in a bodybag, scaring mortician Doug.
JD: (From inside bodybag) Can you press lobby, please?
(Doug screams and begins hitting JD with a fire extinguisher.)
JD: (Shouts in pain and bursts out of bag) Doug!? Why are you hitting me?!
Doug: (Panicked) Cuz I thought you were a dead guy coming back to life.
JD: (Beat) Then why were you hitting me?!
Doug: Dead people should be dead.
- In The Walking Dead pilot, Rick is initially mistaken for a zombie and gets whacked in the head with a shovel. A few moments later, it's noted that as Rick was talking before being knocked unconscious, he's unlikely to be a walker, as they don't talk.
- In Fire Emblem: Three Houses, in the Blue Lions route, after Byleth falls off a cliff and goes into a coma for five years, when Byleth reunites with Dimitri, he initially believes that Byleth is a ghost, there to haunt him because he had thought he had let Byleth die.
- Plants vs. Zombies: The almanac entry for Zomboni mentions that he isn't really a zombie, but some kind of a space-ogre.
- In the SNES Shadowrun game, Jake Armitage wakes up in a morgue after surviving an attempted hit, and promptly terrifies two morgue workers who mistake him for a zombie.
- In the Homestar Runner Halloween Episode "I Killed Pom Pom", after Homestar thinks he killed Pom Pom, Pom Pom tries to prank him by appearing as a ghost that's come to haunt him. Unfortunately, Homestar decides to fight back and pops Pom Pom, killing him for real. Pom Pom later comes back as a patchwork zombie, eager for revenge.
- The Spanish-spoken channel Patico De Hule has the Halloween series, children tales about three friends who goes to ask candies disguised as monsters, but they found real monsters (usually being their imagination, but sometimes they're real). One of the tales is "The Attack of the Zombie", in which the three kids get a short cut for the graveyard after getting full of candy. Then they divise a silhouette and they thought it was a zombie after them (in the end it was the graveyard keeper who helps them when one of them get trapped in a hole).
- A Running Gag in the story segments of Terrible Writing Advice has the Ancient Conspirator appear to the characters using his hologram technology, only for everyone to shout and call him a ghost. This annoys him greatly, especially when he had already corrected the characters in a previous video beforehand and the characters are from a Science Fiction setting.
- In a Boy and Dog strip, Rowan gets told a story where a man thinks some villagers are skeletons because they're so malnourished.
- Inverted in Irregular Webcomic!. Paris is a ghost in a Science Fiction setting, so is sometimes mistaken for a hologram. In a subplot in which the ship's power went out, apparently even most of the readers had forgotten about Paris's true nature, as there were heated debates in the fandom about how Paris's hologram could still be on, to the author's irritation. Paris's official character profile currently specifies that she's "Not a hologram, a ghost. Got it?"
- In this creepypasta, what the protagonist thought was an undead monster was actually a terribly injured person that they could have saved.
- In the Chowder episode "Chowder's Babysitter", a series of events leads to Gazpacho (who was babysitting Chowder at the time) to think that Chowder accidentally landed in Mung Dal's extra-large meat-grinder and that the Chowder that walks and talks perfectly fine before him then and there is actually his restless spirit. They decide that the only way that he could pass on is for him to be flushed down the toilet like a goldfish, Endive's super toilet the only toilet big enough for him to be flushed into.
- Family Guy: In "Boy (Dog) Meets Girl (Dog)", Peter and Lois lead Chris into believing he witnessed the "death" of Arthur Valentine (an imaginary figure they made up for him when he was little), but when it sends Chris into a state of emotional catatonia, Peter tries to convince him that Arthur came back to life by dressing up as him. It works... but now Chris thinks "Arthur" is a zombie and tries to kill him.
- Gravity Falls: The pilot ends with Dipper and Mabel freaking out when they come home to find their Grunkle Stan lurching about, moaning about brains, with red stuff around his mouth. It turns out he ate a strawberry ice-pop too fast and got brain freeze.
- In the Hey Arnold! episode "Dino Checks Out", Dino Spumoni fakes his death to boost record sales while hiding at Arnold's boarding house and having him collect the royalties. When the rest of the boarders find him, they think he's a ghost and Dino rolls with it. By the end of the episode, he regrets faking his death and comes clean to the entire city.
- In The Penguins of Madagascar episode "I Was a Penguin Zombie", Skipper breaks his wing and is sent to the vet, who puts a green numbing cream on it. Later, Skipper tries to escape, but his body is too numb, and he falls on some talcum powder and gets tangled in gauze. At the same time, the other penguins try to break him out and overhear a medical drama on TV, making them think that Skipper has died. When they then see Skipper limping, with slurred speech and ghostly pale greenish complexion, they think he has become a zombie and run for their lives.
- The Simpsons:
- In the Treehouse of Horror episode "I Know What You Diddly-Did", Marge runs over her neighbor Ned and everyone thinks that he died, but later, he comes back. They ask if he's a zombie and he replies that he isn't. Unfortunately, he's a werewolf. Luckily, the Treehouse of Horror episodes are non-canon.
- Comically subverted in "Lisa the Tree Hugger": Lisa is assumed to have died when lightning hit a giant tree she set up camp on. When she reveals she left that night to stay at home, Comic Book Guy points at her and seemingly stutters out "ghost"... except he was actually just calling her a "girl".
- In the South Park episode "Marjorine", when Butters comes back to his parents after faking his death, they assume he's a Flesh-Eating Zombie. The episode ends with him chained up in the basement as his parents kill a salesperson for him to feed on.
Butters: Can I just have some Spaghetti-O's?
- SpongeBob SquarePants:
- In "Squidward the Unfriendly Ghost", Spongebob and Patrick believe that they had killed Squidward (when really it was just a wax model of himself that he had made), so when he emerges from his bath — robed, covered in talcum powder in a bath of steam — they think that he is his own ghost. While at first annoyed, he goes along with it when they agree to be his servants to appease him.
- In "The Nasty Patty", SpongeBob and Mr. Krabs think they have killed the health inspector and try to hide the body. However, the health inspector was just unconscious from almost swallowing a fly, and when he wakes up, the police think he's a zombie and attack him. He passes the Krusty Krab out of fear of getting hit again. He's then accidentally hit by a door.
- Played with in Steven Universe: Lars early in season 5 genuinely comes Back from the Dead, slightly altered, and starts thinking they've become a zombie. Steven insist they haven't, because they can talk and have a (drastically lowered) heartbeat.
- Our legends about the undead are this trope being Truth in Television. Some illnesses and poisonings can leave the victim barely alive, and seemingly dead (which is why wakes and vigils were invented). If the comatose victim recovers with brain damage or delirious (as with a high fever), they can fit the description of stereotypical zombies. In fact, this is how the legend of the revenant got started: plague victims who survived and dragged themselves out of the mass graves they were interred in.
- The very term "zombie" comes from a bit of Caribbean folklore where an unethical priest or sorcerer can poison a person with blowfish toxin, putting them in a coma and slowing their breathing and heart rate to make them appear dead. The grieving relatives bury them, the sorcerer comes along and dig them up, administers the antidote, and keeps the now brain-damaged victim as a slave.