The characters investigate a site with reported paranormal activity. By the end of the episode, they discover that the supposed supernatural activity is nothing but an elaborate hoax taking advantage of local lore to frighten off the curious from discovering and interfering with their main criminal activity.
In the old days, this apparently really worked. Smugglers could scare away intruders by dressing as ghosts. Nowadays, however, this would be a really stupid ploy, as many alleged real life haunted houses and areas of "paranormal activity" are tourist attractions. The criminals wouldn't be able to move for New Agers, UFOlogists, people from shows like MythBusters, James Randi fans, and other rubberneckers. (Not to mention meddling kids.)
The most common subversion is for all — or some — of it to prove Real After All or at least of uncertain origin. Indeed, the investigators may discover the truth and haul the instigators off to jail, and the audience alone gets to see the unambiguous and real apparition. Just as often, at the climax of the story the criminal will be unmasked and attack the heroes just in time to be eaten by the real monster.
This can be a real source of frustration to fans of Speculative Fiction, who tend to be drawn to certain works specifically because of the paranormal elements.
One of the major exceptions to Skepticism Failure. See also Monster Protection Racket, where the monsters are real but they're being set up. The Inversion of a Scooby-Doo Hoax is Mistaken for an Imposter. For the good counterpart, see Scarecrow Solution.
Because the existence of a Scooby Doo Hoax tends to remain secret from the audience until the ending and belie earlier assumptions, mere presence on this list can be considered a spoiler.
When this trope is played out, the real surprise was that in the end, in addition to the kids playing pranks, there was an actual ghost. It was a mostly harmless one, though.
Another episode features a different variation. An irreverent chef comes to judge Chef Kawasaki's cooking skills, but it turns out he was in a costume and working for N.M.E. What's under the costume was worse.
Mazinger Z: In one anime episode, the heroes got reports of a huge, aquatic monster living on a chain of lakes near from Mount Fuji. When Kouji went to investigate to the site, a witch appeared all of sudden and warned him the lake monster would curse him if he did not leave. That woman had been scaring away whoever came to investigate the monster sightings. It did not take long for Kouji to discover that witch was Baron Ashura -Big BadThe Dragon- in disguise and the monster was a Mechanical Beast. Baron Ashura was using the curse hoax to hide their activities (mining the lakebed for uranium to fabricate nuclear bombs).
In one manga chapter, Kouji and his friends go to a hot springs resort. However, the area is apparently being haunted by ghosts. Boss is terrified but Kouji does not believe one word of it, so he and Sayaka set to investigate what is happening. Quickly they discover the ghosts in reality are androids commanded by Count Brocken, one of the Co-Dragons of Dr. Hell.
At least one episode of Detective Conan / Case Closed did this. The protagonists receive a letter from a dead man and investigate a series of murders framed on his ghost. In the end, it turned out to be his son who was supposedly killed along with him, posing as a woman, seeking revenge for the death of his father.
A number of other episodes of Conan did it, too. Since the series is set in a strictly rational world, any invocation of the supernatural can be assumed to be a Scooby Doo Hoax. (That doesn't stop normally-stalwart Action Girl Ran from cowering whenever she suspects she may be up against ghosts, however.)
Taken in a more dark direction in The Kindaichi Case Files. Most of Kindachi's cases involve murderers who disguise themselves as a feared monster from local folklore, and kill their victims in ways relating to the legends surrounding that figure (eg, a killer disguised as a legendary headless samurai ghost decapitates all his victims.) Kindaichi gathers clues leading up to a dramatic unmasking of the "monster" at the end of the story. Different from your standard Scooby hoax in that most characters understand from the get-go that this isn't a real monster, just a psycho in a disguise. Inverted in that this arguably makes it more scary...
There's always one character who really believes that the killer is actually the legendary monster in question. That person almost always ends up dead, and his/her death leaves everyone else with eerie, lingering doubts about the killer's humanity.
Except in one story where the person who believed in the monster was actually the killer.
During the Thriller Bark arc of One Piece, the supernatural things like cerberus, ghosts and zombies are later revealed to be the work of Gekko Moria and his crew, all of them Devil Fruit users.
In Usagi Yojimbo, the hero comes to a tavern that borders a haunted woods. Once there, Usagi is forced to take a dare to explore the woods for an item there. In the woods, Usagi has a terrifying experience facing many of the monsters he has faced before and slashes out wildly before discovering that they are all elaborate puppets and he catches the puppeteers in this hoax. However, when he learns that the hoax, which is basically harmless, is helping their poor village prosper, he agrees to play along while allowed to get the quest object to win his wager.
The original purpose of the comic-book character Dr. Thirteen in DC Comics was to travel to supernatural sightings and debunk them. When he was integrated with the rest of the characters in a shared universe, this naturally led to some problems as the supernatural does exist in The DCU. This was largely "solved" by making Dr. Thirteen a Flat Earth AtheistButt Monkey, but it's not all bad news for him. Apparently, his skepticism means he's somewhat resistant to magical effects (in the DCU, you have to genuinely believe in the supernatural before it will work for you) and he can and does provide alternate scientific theories that sometimes turn out to be right.
In the Donald Duck comic "The Old Castle's Secret," the ghost of Sir Quackly McDuck turns out to be a jewel thief using "invisibility spray." Carl Barks commented that he wanted to do a "Haunted Castle" story but at that time including "real" supernatural events such as ghosts in a Disney comic was strictly taboo.
Another Carl Barks example comes from the story "Terror of the River", where Donald and his nephews investigate a giant serpent-monster terrorizing a waterway. The "monster" turns out a realistic inflatable model controlled by a guy in a submarine. As opposed to some of the other examples on this page, the perp had no ulterior motive-he was just a Jerk Ass who liked scaring people for the heck of it.
Less notable Donald Duck and Mickey Mouse stories have done this over and over again in various forms. An inverted version where the heroes scare away the villains from something being protected is about as common. The twist where some of it is shown to be real after all appears frequently in both versions. One story-within-a-story, written by Goofy, was a parody; in the end, the answer to how the villain was able to create the appearance of all those supernatural monsters is explained by saying that, well, he was a magician, and magicians do all kinds of tricks we can't explain, so why should the story do that?
The Golden AgeCaptain America, strangely enough, was written (at least in most stories available in reprints) as a non-supernatural horror comic. It was thus full of this sort of hoax (sometimes with fake supernatural creatures that are real murderers) as well as monsters created by science, ordinary killers with horror themes, etc.
The Antarctic Press comic Bad Kids Go To Hell reveals all the supposed supernatural scares were nothing more then illusions to off the detention kids and make money from their deaths.
Despite stereotypes to the contrary, a large number of the aliens that Batman fought during the Silver Age (especially in his own books) were actually ordinary crooks dressed up like aliens. In one case, a gang of crooks actually made up an entire planet, built fake alien technology, and pretended to be invading Earth simply to cover up their scheme.
Though he really did fight and kill some real vampires in the Golden Age.
Variation: Superman and the Iranian superhero Sirocco once took down an apparent terrorist squad, only for Sirocco to reveal that they are just people who pretend to be terrorists. By scaring people into evacuating places with phony bomb-threats and such, they can rob places at their leisure.
Sirocco: They are common thieves. Seeking to profit from people's fears.
In Dr. NoJames Bond is told that the titular villain manages to keep his private island "private" by the presence of a dangerous fire-breathing dragon that kills any locals who trespass on his property. It turns out to be a tank painted to look like a dragon, and armed with a flamethrower. Partly justified in that the tank doesn't show up until it gets dark, so it's harder to figure out its true nature.
In Live and Let Die, as in the novel, the villain uses Voodoo, as his mistress/servant Solitaire, who has "the power of the Obeah" (which supposedly lets her see the future), to maintain an iron grip over his island nation and drug empire. He even has someone pretending to be Baron Samedi on his side, plus a host of traps and tricks. Subverted in that Solitaire seems like she really does have the power to see the future, and the ending has Samedi (who was apparently killed by snakebite earlier) riding the front of a train, laughing, implying he was Real After All. Most of the other stuff really is just an elaborate hoax, like scarecrows promising death to anyone who trespasses on the poppy fields (and hidden cameras and guns in case you don't take the hint).
The movie Volver: The whole population of a superstitious village is convinced that the spirit of a woman who died in a fire has come back to take care of her sister in her old age. When the sister dies, the ghost moves in with her daughter. It turns out that she never died in the first place; she burned the house where her husband and his lover were sleeping to the ground, and the lover's charred body was thought to be hers. She pretended to be a ghost to escape a murder investigation.
Friday The13th Part VA New Beginning is a semi example. The killer turns out not to really be Jason, but a copycat. Although it is one serial killer imitating another, he is pretending to have come back from the dead, even though the genuine Jason wasn't supernatural by this point and was in fact genuinely deceased (he would become the indestructible zombie we all know in the next film).
The 2009 Sherlock Holmes movie uses this, with apparent Big Bad Lord Blackwood deliberately cultivating a reputation as a fearsome Evil Sorcerer, culminating in rising from his grave following a hanging, all as part of his Evil Plan to seize control of England. He's really "just" a Magnificent Bastard with good connections and an eye for the theatrical, and Holmes figures this out and explains it at the climax before exposing Blackwood for a fraud. Holmes does mention, though, that Blackwood performed all his spells and rituals perfectly and therefore he'd better hope it was all fake, or else Satan's due a soul...
Famously subverted in the Sleepy Hollow movie. In the original story by Washington Irving, the Headless Horseman was an elaborate prank to scare an aloof schoolteacher. In the film, it really exists. In a nod to the original story though, the first run-in Ichabod has with the Horseman is a fraud - a jealous Brom Bones was disguised as the being as a prank. He also initially believes the Horseman really is a fraud, and sets out to "expose" him.
Played with in the French supernatural thriller Vidocq: powerful men die one after another from a lightning strike, bursting into flames in the process. It turns out that they were narcissistic perverts with a desire for young virgins. A sophisticated lightning rod mechanism along with a piece of gold in each of the men's hats, and gunpowder dust on their coats resolves that somebody simply wants to make a demonstration of divine retribution on these horrible people. Then it turns out that the killer was a supernatural creature all along, and used this method to hide his true nature, and the true motivation for the murders.
The Bollywood film Joker has an isolated village fake the landing of aliens to attract attention to their Dying Town. At the end, a genuine alien appears.
Washington Irving's 1819 short story The Legend of Sleepy Hollow strongly implies that Brom Bones eliminates Ichabod Crane as a rival for his lover's hand by dressing up as the Headless Horseman and scaring him out of town.
Most of the Leaphorn/Chee mysteries by Tony Hillerman, with the supernatural elements in this case coming from the myths of the Navajo or other Native American tribes of the American Southwest.
The Phantom of the Opera. The entire book is about the investigation of the "ghost" who forces the opera house management to bow to his whims; eventually, it is discovered that he is in fact a deformed genius hiding out in an elaborate lair beneath the building.
Terry Pratchett's Maskerade, being a parody of The Phantom of the Opera, had one member of Ankh-Morpork's Opera House dressing as "The Ghost", terrorizing and even killing members of the cast in order to hide his embezzlement. At the same time, there was an actual "Ghost" roaming the opera house who gave nighttime lessons to promising singers and left rose stems scented with rose oil to reward exceptional performances.
Who also was a member of the opera house.
Note that the Opera Ghost almost never pretends to be actually a ghost. He's perfectly happy to be a guy in a mask...
Although those scented rose stems actually do bloom into ghostly roses when in darkness. At the end, Agnes laments that she'll probably never know how the "Ghost" managed that. But Discworld runs on Clap Your Hands If You Believe, so it might have been enough that people thought the Ghost was supernatural.
In the James Bond novel Live and Let Die, Mr. Big cultivates an air of voodoo around himself to deter investigation into his operations. Take a look at the entry in Films.
Virtually every single installment in the Austrian Knickerbockerbande youth crime fiction series, to the point where the reader would know from the start that the supposed haunting was fake, and the main interest was in finding out how the hoax worked.
In Alan Mendelsohn, the Boy from Mars by Daniel Pinkwater, the Wozzle is an invisible monster employed by the Nafsulian bandits Manny, Moe and Jack to terrorize the citizens of Waka-Waka. It turns out to be no more than the three villains themselves.
In Bitter Gold Hearts, Garrett recalls investigating one of these cases, in which a murder was rigged to look like a werewolf attack.
These plots happen to Nancy Drew and the Hardy Boys all the time in their books, and have spilled over into the former's video game franchise.
This appears regularly in The Three Investigators, who generally deal with spooky cases. The Coughing Dragon has a sea-living dragon that is actually an antique submarine, used to rob a bank; The Dancing Devil has an ancient Mongolian spirit which literally is a guy in a suit trying to stop an old artifact being returned to Mongolia from a rich American collector.
Carnacki The Ghost Finder has at least one case like this, with smugglers faking a haunting so they can use an abandoned building.
In The Saint short story "The Convenient Monster", a murderer tries to make his killing look like the work of the Loch Ness Monster.
In the The Mad Scientists' Club book, it is played straight in The Voice in the Chimney, but subverted - perhaps - in The Secret of the Cannon.
The first Calendar Mysteries book revolves around an alien hoax that the big kids pull on their younger siblings out of revenge.
In the Penny Parker book Hoofbeats on the Turnpike, Joe Quigley dresses up as the Headless Horseman of Sleepy Hollow to spite Matilda Burmaster.
In Larry Niven's "Night on Mispec Moor", a mercenary assumes the zombie-like creatures chasing him must be this trope. They're The Virus instead.
A gang of bootleggers do this this keep people away from their hideout in You're a Texas Ranger, Alvin Fog by J.T. Edson.
Fairly common in works of Agatha Christie. The usual plot is that one or more mysterious deaths occur, and people suspect supernatural activity behind it. At the end it turns out that the whole thing is just a cover made by the killer to confuse the cops.
In Village Of The Vampire Cat, a gang covers up their activities by making the village they are robbing think there is a demon on the loose. This includes a ninja using a grappling hook (painted black to make it almost invisible at night) to tear people's throats out at a distance. They also sell people odorless charcoal. The people pass out from carbon monoxide poisoning (since they don't smell smoke and don't think to ventilate the room) and think the demon is draining their lifeforce.
An example of a series that used this as a standard device even before the trope namer was born: The Simon Ark mysteries involve a wanna-be Occult Detective who claims to be the Wandering Jew, and whose goal is to fight Satan—but the evil he uncovers invariably turns out to have a mundane explanation.
Live Action TV
Many episodes of Banacek featured apparently supernatural events, debunked by the title character in the climax.
Usually reversed in The X-Files, where it's almost always really a supernatural occurrence, but it also had criminals playing dress-up to distract people from their actual crimes. And sometimes they did both.
For example, Mulder is on the trail of murderers whose killings look like vampire attacks. The "vampire" angle is so obvious and unhidden that Mulder assumes that it's actually an example of this and that there are no vampires involved. Then he finds the killers, who seem pretty much human. Then he finds out that they actually are vampires, but that they play up the movie vampire act when they kill, so that anyone who arrests them will be laughed out of court.
The novel Mr. Monk on Patrol has Monk and Natalie initially bunked at a hotel that is supposedly haunted. And during their first night in Summit, New Jersey, the ghost tries to attack Natalie, but Natalie fights back and the person playing the ghost manages to escape, then is caught by police. It turns out Monk had found some details while unpacking in his room that he thought were suspicious, and this led him to more clues that told him how the "ghost" story was fabricated.
"Mr. Monk and the UFO" had a variant: Monk and Natalie are driving in the country when their car breaks down in a small Nevada town. While Monk is trying to get a cell phone signal, he ses a small UFO fly overhead. It hovers for a few seconds over them, then flies away. The next day, Monk files a report with the sheriff. The next night, Monk, Natalie and a hotel manager see the UFO.
"Mr. Monk and the Voodoo Curse" is probably one of the top examples. Two random people are killed in freak accidents (a elderly power walker who gets hit by a baseball knocked over a fence, and a guy killed by lightning while golfing in a thunderstorm), and when people go to their apartments to pack their stuff up, they find voodoo dolls that are dated a few days before the recipient's death. Monk is brought in to investigate, due to the case being considered weird right away by Stottlemeyer and Disher, but even he is baffled by the circumstances. Shortly after he takes the case, a third doll victim occurs - the wealthy founder of an electronics company - and it is the first one to have a body; who died of an apparent heart attack. Then Natalie, who is afraid of voodoo, receives a doll in the mail that warns her she will be decapitated. Monk eventually finds that Angeline Dilworth, a paramedic and niece of the third victim, was responible for sending the dolls and was trying to cover up the death of her uncle, the only one of the three victims to actually be a murder. The other two victims were the freak accidents they were supposed to be, and Angeline had been the EMT who responded to both calls. She had stolen each accident victim's house key and used that to break into the respective victim's house to plant a customized voodoo doll.
Either Inverted of Subverted trope in an episode of Psych. The monster is attempting to attract people to his "haunted" camp.
The titular investigation team of the show fits the trope, in that Sean feigns Psychic Powers to solve crimes.
There's also an episode where Shawn and Gus are investigating a supposedly haunted house and the perpetrator of the Scooby Doo Hoax turns out to be Shawn himself.
There was yet another episode when a local legend about a suicidal sorority girl was played with for revenge.
And now yet another where Shawn and Gus are looking into a UFO sighting, becoming more and more convinced it's real, until they find out it was all a cover-up for an actually real corporate conspiracy and are almost Killed to Uphold the Masquerade. Not an exact fit because they were trying to attract attention to the person who thought he saw the UFO rather than get rid of attention to a place or thing. Could be an inversion of sorts? Or just playing with it.
This show obviously loves this trope since the 2010 Halloween episode involved murders of amusement park employees that first appeared to have been committed by the ghost of a boy who died in a Ferris Wheel accident a decade earlier. It turned out to be the dead guy's girlfriend dressing as him in order to get revenge.
In "The Rescue", the 'alien monster' terrorizing the shipwrecked colonists turns out to be one of the colonists in disguise.
In "Colony in Space", the 'alien monster' terrorizing the colony of the title is being faked by a mining company that wants the colonists off the land so it can stake a claim.
A slightly different version of this is used in "Invasion of the Dinosaurs". In an interesting subversion, the eponymous monsters are indeed real, brought forward in time from their own prehistoric period, but they are merely there to scare people away in order for the real evil plan to be enacted.
Inverted in "Curse of the Black Spot". The "siren" isn't a siren, or a ghost, or a green singing shark in an evening gown, but neither was she pretending to be. This was merely the terrified assumptions of the crew of a pirate ship who had no way of comprehending that she was an emergency medical hologram trying to heal their injuries. Her scarier moments are merely because she's a bit overprotective when it concerns her patients.
Inverted in much of the New Who - see School Reunion and episodes with the Slitheen, as well as many others. See this comic◊, which directly addresses this trope.
The Pushing Daisies episode "Girth" does this rather more violently, with people being killed, apparently by a ghost. It turns out to be someone who is very much alive.
Played with in the sense that the murderer is disguising herself as someone who isn't really dead either
In one episode of Friends, Joey does not want Monica and Chandler to buy a new house. He meets a young girl, played by Dakota Fanning, and suggests that she tell Chandler a ghost lives in the house so that they will be scared away. Fanning replies, "What are you, like, eight?"
When Joey confesses his plan to them, Chandler and Monica turn it around and tell him that the only little girl who lived in the house died twenty years ago. This scares Joey until they tell him that they're just messing with his head. Joey replies, "That's not funny! You know I'm afraid of little girl ghosts!"
Done early on in the original Dark Shadows, before genuine supernatural elements were introduced to the program.
The Monkees episode "Monkee See, Monkee Die" with a faked haunted mansion.
Happened in at least one episode of Far Out Space Nuts which involved a holographic disguise belt.
An episode of iCarly has the group searching for Bigfoot and seemingly trapping him, only to discover it's a fake and that it's the Bigfoot expert they had on their webshow earlier in the episode creating hype for his new book. Freddie lampshades this by stating this is a "Scooby Doo Moment".
Subverted, in that something (which is strongly implied to be the real Bigfoot) steals their RV at the end of the episode.
The Invisible Man had the heroes pulling off one of these: The Agency is ordered by government higher-ups to have Fawkes pose as a ghost in order to convince the superstitious dictator of a Banana Republic to get rid of a biological missile system that could potentially be used against American targets. However, it turns out that Chrysalis is also running a hoax of their own to convince the guy to keep the missiles. Hilarity Ensues.
In The Outer Limits episode "The Awakening", a rival company uses fake alien abductions to traumatize clients of a company and discredit their brain implants.
One episode of Gilligan's Island had a "ghost" who was haunting the island. He was actually a man trying to either scare them off the island or kill them because he and his cohorts were trying to secure "off-shore oil rights." When he thought the castaways were dead and came back as ghosts to haunt him, he fled the island. Incidentally, the "ghost" was played by Richard Kiel, who played "Jaws" in the James Bond movies The Spy Who Loved Me and Moonraker.
On The Wild Wild West, in the episode "The Night of the Colonel's Ghost," a series of murders in Gibsonville, supposedly the work of the eponymous ghostly colonel, are actually the work of the colonel himself, who faked his own death and is now trying to drive everyone else out of town so he can search for his father's fabled treasure.
A variation appeared in a Babylon 5 episode, where a crook managed to obtain a Na'ka'leen Feeder (a semi-sentient monster that feeds on memories) and, to scare into submission other crooks and the security, dressed it like Kosh to appear under Vorlon protection. Sadly for his scheme, the Security identified the Feeder even before seeing it and a run-in with a witness made them realize the 'Vorlon' was an hoax.
Done by the bad guys in the Modesty Blaise storyline "The Vampire of Malvescu".
Sometimes this would show up in The Phantom - the eponymous hero would stumble upon a mystery, get the native's crude and inaccurate view of the situation (e.g. a mighty bird dropping food), and eventually figure out it was just criminals using modern technology (the bird turns out to be a plane dropping supplies). Usually he'd follow this up with a Scarecrow Solution, convincing the criminals he's a ghost.
Adventures in Odyssey: "Blackbeard's Treasure", a reclusive old man dresses up as a pirate ghost to scare the local kids off his land. There was hidden pirate gold on his land, but in a slight twist, the old man didn't know about the gold and didn't care about who got to keep it, he just wanted to be left alone.
In the White Wolf RPG Changeling The Lost, there is an odd case of this. The genuinely supernatural Changelings of the Scarecrow Ministry have a tendency to create elaborate Scooby Doo Hoaxes to keep people away from truly dangerous beings such as True Fae, werewolves and Spirits (either through fear of the hoax or through being attracted to it rather than the real monsters). Of course, sometimes they go a bit too far, and become the things they impersonate.
1st Edition module U1 The Sinister Secret of Saltmarsh. A group of smugglers tries to make the house they're operating out of appear to be haunted to keep the townsfolk of Saltmarsh from investigating.
Another band of smugglers from Dungeon magazine got their hands on a magical boat that could travel underwater, so used seaweed and ghoul costumes to perpetuate an "undead sailors from the deep" Scooby-Doo Hoax.
Call Of Cthulhu supplement The Asylum and Other Tales, adventure "Westchester House". The Investigator PCs will hear stories of several unnatural events that indicate that the house is haunted, but they're all fake, mostly done by people trying to make it appear that way to cover up their own schemes.
The Neverwinter Nights 2 mod The Maimed God's Saga looks like it is setting up as one of these, then the actual nature of the villain's plot is revealed (a Malarite experiment to breed invincible werewolves, as a matter of fact).
The Captive Curse is a full-on Deconstruction of this trope, in which the monster sightings are variously suggested to be a Scooby-Doo Hoax, a reverse Scooby-Doo Hoax intended to draw in tourists, a kid's prank, or a genuine supernatural event. Eventually, it turns out to be a hoax OF a reverse Scooby-Doo Hoax, intended to discredit the castle's owner by making him look like he got Nancy killed with an insane publicity stunt.
Persona 4 is basically modeled after this trope. Heck, even the characters resemble the good ol' Scooby Gang.
Double Switch: Roughly around the middle of the game, an Egyptian mummy runs around trying to trap and/or kill people. It's Eddie in disguise, and he dressed up like one so that he could get an Egyptian statue without anyone figuring out it was him.
Kate Beaton's comics have, in a couple of recent strips, featured "Mystery Solving Teens", which parody the entire genre. Having been enlightened to a mystery in the area, the teens go off and smoke for a while, then Ass Pull a name or group who was pulling the Scooby-Doo Hoax for the benefit of the person begging their help.
Bloody UrbanZig-Zags this trope rather confusingly by having one type of monster dressing up as another type of monster. Specifically, Shaun (a Vegetarian Vampire who feeds on livestock) dresses up as a Chupacabra in order to get free food and not get caught.
The Trope Maker might be "Felix the Ghost Breaker" (1923), an early Felix the Cat cartoon. In a direct anticipation of the later Scooby formula, the crook of the moment disguises himself as a ghost to scare an old farmer off of his land. Ironically, the cartoon didn't explain how the crook's disguise enabled him to do real ghostly things like fly, disappear, and walk through walls. Movie reviewers of the time complained about the cartoon's lack of logic.
Virtually every episode of the original Scooby Doo, naming and codifying the trope. In the later shows and most of the movies, this would often be subverted, averted, lampshaded, and just all-around played with as often as it was played straight— at least some of the monsters were real. In roughly chronological order:
Scooby Doo Where Are You: Played straight through most of the entire run. The sole exception is the episode "Foul Play in Funland" — the out-of-control robot terrorizing an elderly couple's amusement park turned out to actually be an out-of-control robot, originally built by the elderly man as an assistant.
Also zig-zagged in the episode "Haunted House Hang-Up". The heroes spend the episode chasing (and being chased by) one monster, who turns out to just be a man who dressed up to protect his own property from would-be thieves. The real criminal, who is indeed after the treasure the owner is protecting, is unmasked at the end.
Scooby-Doo and the Witch's Ghost: Subversion - The entire town pulls a Scooby-Doo Hoax for the opposite reason: to attract tourists. The real supernatural threat is actually working with the gang to investigate the fake one!
Scooby-Doo and the Alien Invaders: Subversion - there are both fake aliens and real aliens, but the real ones are good.
Scooby Doo And The Cyber Chase: Subversion, with Justification: The monsters are the 'same' as those found in many of the early hoaxes. But because the cast were in a video game of their own adventures, the monsters weren't people in costumes. Cue Not A Mask scare when Scooby Doo tried to unmask one of them after Lampshading the trope.
Scooby Doo In Wheres My Mummy: Subversion, then Inverted. It looks like it's set up to all be real, but by the end the gang learns it was Velma who was pretending to be the monster (after faking turning herself into stone) to protect a Egyptian dig and scare away exploiters, doing exactly what almost everyone the Scooby Gang had unmasked did. Although for more noble purposes.
Scooby Doo Pirates Ahoy: Lampshaded and Discussed: The gang handily debunk every one of the dinner-theater monster mysteries which the cruise director had planned for a multi-week cruise on the first day of the voyage, believing them to be actual Scooby Doo Hoaxes. They then remark on how they kind of do this thing all the time, even dismissing a character who angrily asks them "if you're so good with mysteries, where's my watch!?"
Scooby Doo Mystery Incorporated: Plays with it. Has a similar idea to Witch's Ghost of using the fake monster attacks as part of the tourism by pretending they're real. They even arrest Mystery Inc for trying to stop the criminal. One episode averted the trope by having the villain as an insane Trap Master, who never tried to hide the fact that he just an ordinary man. However, in a subversion, his insanity is strongly implied to have been caused by an Artifact of Doom.
And later inverted in the episode "Wrath of the Crampus", when it's revealed that Mystery Inc. created the monster to distract the real villains and acquire their stolen segments of the season's MacGuffin.
The supernatural is very real in this version of Scooby-Doo however, as evidenced by the mysterious mind-control properties of the Planispheric Disc and the two real ghosts so far seen in the show.
Also in the episode "The Horrible Herd", there isn't even a mystery, its the gang having to save the town and its residents from being torn apart by REAL mutant cow/piranha/bee creatures.
The "Trick or Techrat" episode of Jem had Eric, Techrat, and a one-shot character attempting to pull off a "Scooby-Doo Hoax" to shut down a opera house.
Parodied in the South Park episode "Korn's Groovy Pirate Ghost Mystery". It turns out that all the paranormal occurrences were the result of Priest Maxi trying to stop the Halloween Haunt- but the "logical explanations" include such ridiculousness as Maxi using a flashlight to create a giant ghost ship and a dog apparently swallowing an entire corpse whole.
DuckTales played with this sometimes (despite the presence of real supernatural elements in the show's setting). In one episode, Scrooge inherited an ancestor's manor in Scotland, only to find it was "haunted" — by modern druids trying to scare away interlopers from their ancestral ritual site. In another, Scrooge opens a hotel but is plagued by two ghosts: a thief using invisible paint to steal jewels and the paint's inventor trying to get it back.
These plots were adapted from Carl Barks's Hound of the Whiskervilles and The Old Castle's Secret (see above).
An episode of Invader Zim featured Dib actually unveiling a hoax about a man who thought he was part chicken, when he was just an insane man in a chicken costume. At the end, he says that paranormal investigators can also debunk hoaxes like this, but the reports misinterpret his message and think that all supernatural claims are hoaxes.
Bummer fakes a haunting of a unused luxury suite so he can keep it for his own personal use in an episode of Stoked!.
Double Subverted in Avatar The Last Airbender when the gang meets a man who masquerades as a swamp monster to protect his home. The thing is, the man maintains the disguise through genuine magical powers: bending the water within the vines to make strong, self-healing plant armor. But in this setting, that's not too unusual and people are more concerned by the fact he doesn't wear pants.
The gang actually use one of these in "The Painted Lady" to scare off a bunch of Fire Nation soldiers and save a small town. Subverted again as there really was a Painted Lady who thanks them for their work.
Of course, the Spirit World is a very real place in the Avatar-verse, so...yeah.
Foxy Love in Drawn Together would use this trope often after "solving" a crime. However in one instance she mistook the man's actual face for a mask and ripped his head off.
Phineas And Ferb featured this in the episode "Ladies and Gentlemen, Meet Max Modem". Dr. Doofenshmirtz's evil plot of the day was to use a holographic projector to stage an alien invasion and scare the citizens of the Tri-State Area into accepting him as their ruler.
This was basically the premise for The Funky Phantom, except Mudsy and Boo were real ghosts, even if they were good guys.
Yogi's Great Escape plays with the concept; When Yogi, Boo-Boo and the three toddlers run into Mumbo-Jumbo Swamp while fleeing their pursuers, they find an old steamboat to hide out in. At first, it looks like it's haunted with spooky effects and a ghost chasing them around. When they hide in a boat and the ghosts finds them, however, the 'ghost' recognizes Yogi and Boo-Boo and reveals himself to be Wally Gator. He'd been haunting the boat whenever his self-made alarm rang in order to scare away any zookeepers that wanted to catch him. It's later subverted when Yogi tries to repeat the trick a little later and manages to mess it up himself, only for it to turn out that there'd been a real ghost on the steamboat all that time, who chases everyone off it.
Occurs in the Futurama episode, "Fry and the Eggman" when Fry's new pet (a bone vampire) gets framed by a man in a costume.