When a character convinces another (perfectly healthy) character that they are ill, often in order to get them out of the way for a little while, or just to mess with their head. To accomplish it, they may employ fast talking, medical jargon, obviously fake medical devices, etc.; they might even make up a whole new disease. Expect them to say "You don't look so good," or "You're a very sick man."
The victim almost always falls for it, often expressing a desire to "go lie down". May result in Your Days Are Numbered and/or Mistaken for Dying. This trick cannot, however, actually hurt or kill a person like in the case of the Compelling Voice or Your Mind Makes It Real. Typically Played for Laughs. Compare Gaslighting, and You Don't Want to Catch This.
In an inverse, sometimes a fictional disease will be whipped up that has no symptoms and apparently only targets healthy people and is allegedly fatal. This is employed almost exclusively on very gullible people.
A Sub-Trope of Hypochondria. Compare Münchausen Syndrome By Proxy, which involves actually making someone sick in order to get positive attention from others for taking care of them. See also Faking Another Person's Illness, in which the goal is to persuade a third party. If someone tries to scare someone with a story concerning a disease that, for instance, "is especially bad for X" when the listener is an X, then it's overlapping with Scarily Specific Story.
- The manga version of Excel Saga had a chapter in which Iwata was Mistaken for Dying, which ended by revealing that his doctor (and Sitcom Arch-Nemesis) had faked his diagnosis. The next chapter started with the team's mentor Kabapu announcing that Iwata had died; the doctor had only exaggerated the symptoms to try to get the case into a medical journal.
- In Gintama, Kagura fakes being deathly ill on one occasion to make Gintoki and Shinpachi appreciate her more and wait on her. It ends up backfiring on her when she really does get sick as a result of her poor lifestyle, plus Okita sees through the ruse instantly and makes things even worse for her by somehow convincing Gintoki that she's dead...
- In Joker's Last Laugh, a doctor fakes a medical report to con The Joker into believing that he's dying. The doctor hopes to "scare him straight". Instead, the Joker goes through the stages of grief in five minutes and after reaching "acceptance" decides to go on a final rampage of such hideous scope that it becomes a Crisis Crossover.
- Similarly, Clock King started doing crime because of a doctor telling him he was dying so that his sister could live comfortably when he was gone. However, it turned out that this was genuinely an accident and the doctor was mistaken. As you can imagine, when he got out of prison Clock King tried to kill him for ruining his life.
- In a 1940s Superman story, "The Three Kingpins of Crime," Superman has to prove a gangster killed the wife of a prosecuting attorney. He tells the murderer that if he was at the victims house, hiding in the bushes, he would have been exposed to poison ivy. To prove the man is guilty, the policeman simply has to wait until his rash appears. Sure enough, the man becomes so itchy that he confesses to the murder in exchange for medical attention. It is then revealed that the bushes the criminal was hiding in were not poison ivy and it was his guilty conscience that caused him to itch.
- In Disney's Pinocchio, "Honest John" does this to get Pinocchio to go to Pleasure Island.
"Just as I thought. A slight touch of monetary complications with bucolic semilunar contraptions of the flying trapezus!"
- In Shrek, Shrek and Fiona convince Donkey that he doesn't look so good. They were actually just using him as an excuse to spend another day together, but he's so neurotic that he falls for it anyway.
- In the 1937 movie Shall We Dance?, Peter Petrov talks his nagging manager into becoming seasick so he can go on a date without interference.
- Zigzagged in Joe Versus the Volcano. Joe was a hypochondriac to start with. Then his doctor informed him that he had a fatal condition, completely unrelated to all his symptoms. No longer having any reason to worry about his health, he immediately stops fretting about his imagined illnesses and feels much better. In the end it turns out he wasn't sick at all, the doctor was part of plot to get him to agree to be a Human Sacrifice.
- In Escape From The Newsroom, several people try to make Ken Finkleman believe he is sick due to exposure to anthrax.
- In A Day at the Races, this is the reason Dr. Hackenbush is so well trusted by Mrs Upjohn:
- Mrs. Upjohn: Why, I never knew a thing was wrong with me before I met him.
- In The Secret of Dr. Kildare, a young woman given to nervous headaches is convinced by a meddling friend that something is seriously wrong with her, and taken to a cancer quack.
- In The Two Towers, Wormtongue has convinced King Théoden that he is far too ill to lead men into battle, possibly with the aid of a Compelling Voice. Gandalf convinces him otherwise.
- Used non-humorously in the novel Angel's Kiss. A character gets petty vengeance on an apparently healthy man who slighted him by telling him that he looks ill. He is so convincing that the man goes to his doctor—and discovers he has cancer.
- In Mind Games, the protagonist develops a psychic ability that has this effect. She has hypochondria herself, and can get rid of her health anxiety by pushing it into others. This doesn't actually make them ill, but their resulting actions might.
- In the first installment of Gordon Korman's Macdonald Hall series, George is already a hypochondriac, but Boots makes it worse by inventing a deadly tropical epidemic and convincing George that he has it.
- Forms part of the opening of Three Men in a Boat, in which Jerome reads a medical dictionary from cover to cover and becomes convinced that he is suffering from every single disease described therein. Except housemaid's knee.
- In the first half of The Twits, during which Mr. and Mrs. Twit play nasty pranks to get revenge on each other, Mr. Twit uses this for his biggest and best prank. Every night he adds a tiny sliver of wood to the bottom of his wife's chair and cane, convincing her that she's shrinking. He tells her that the only remedy is to be stretched, by tying her to a bunch of balloons and stakes so that she's painfully stretched by them both.
- In the short Hercule Poirot story "The Adventure of the Egyptian Tomb", the resident doctor diagnoses leprosy in his friend who is actually suffering from a minor skin ailment, driving the poor man to suicide in order to inherit his money.
- In Ripley's Game by Patricia Highsmith, Villain Protagonist Tom Ripley convinces an enemy that he is dying, as part of a plot to manipulate him into acting as an expendable assassin.
- The Stainless Steel Rat for President. Jim and Angelina steal a spaceship by pretending to be a doctor/nurse tracking down a rare disease that makes the victim act like a dog. Sure enough one of the crew starts growling and barking...because Angelina drugged him with the throat swab used to test him. This gives them an excuse to quarantine the rest. However the plan goes wrong when Angelina gets captured. Jim surrenders himself but is able to scratch the Big Bad with his fingernails, infecting him with a 'deadly virus' that only he has the antidote for. The plan works and they are both released in exchange for the antidote, which is just water, as the virus is only a mild toxin that wears off.
- Happened a couple of times on M*A*S*H as the surgeons used it to get an annoying superior officer out of the way for a little while. Once (possibly the last time they used this device) Hawkeye and BJ got in a serious disagreement, because Hawkeye removed the appendix of a person who didn't need his appendix removed.
- Frequently occurs in Sanford and Son whenever Fred G. Sanford fakes a heart attack, but Lamont usually knows him better than that and catches on to his routine as the show progresses.
- An episode of Malcolm in the Middle revolved around the brothers trying to dispose of evidence of what they consider to be the worse thing they ever did: convince their mother she had cancer so she'd be too distraught to get angry at them for their poor report cards.
- In an episode of House, House managed to convince an airplane full of people that the symptoms of the disease they already believed they might have caught included things like a spasming left hand. Right on cue, they all starting having those symptoms, proving that they were suffering from mass hysteria.
- In an episode of Drake & Josh, Megan somehow tricks Drake into thinking he has a horrible disease that can only be cured by soaking his hands and feet in several gallons of lizard pee.
- Leverage, "The Order 23 Job." The team notices a Corrupt Corporate Executive about to go away to Club Fed seems to have germophobia... so they drug his water, send him to the hospital, then hijack an entire wing to make him think he's ended up in the middle of a pandemic. At one point, they manage to give the target a real nosebleed entirely through the power of persuasion.
- In another episode the crew convinces the curator of a museum that he has fallen ill due to a mummy's curse, or at least from fungi in the sarcophagus.
- In an episode of Full House, Joey brought home two Counting Crows tickets and Michelle got upset that her sisters would get to go and she wouldn't. Danny made them draw straws and when Stephanie lost, she and DJ concocted a plot to convince Michelle she had the made-up "Shmedrick's Disease" so she would have to stay home. It almost worked until Michelle gave them a heartfelt speech about how she just wanted to go to the concert so she could be cool like her big sisters.
- In an episode of Are You Being Served?, the staff convince Mr Rumbold that he's suffering from some unspecified stress-related disease, and that he should dismantle the security cameras to save himself from the urge to watch them all the time.
- In one episode of Mission: Impossible, the team tricked a man who mass-produced counterfeit pharmaceuticals into believing that he'd contracted the disease that his phony drugs are supposed to cure, in order to make him give an Engineered Public Confession about the quality of the medicine the doctor at the clinic (Actually Barney) wanted to give him.
- In Dilbert, Dilbert convinced Stan the Marketer that he had altered his DNA through his computer. Being a marketer (whose career is built upon unverified consumer anecdotes), Stan actually believed him and started growing whiskers and a cute little nose. Eventually Dilbert "cured" him by saying a report taken out of context from an unrelated focus group said he wasn't changing after all.
- At least one Garfield strip has Garfield cause a dog to faint doing this.
- Bartolo, the Count, Figaro, and Rosina all (for very different reasons) use this on Don Basilio in Rossini's The Barber of Seville.
- The Trickster class in Final Fantasy Tactics A2 cause Standard Status Effects through illusion and manipulation. In terms of gameplay, these are identical to the regular effect, sometimes more plausibly than others (taunting to induce Berserk makes perfect sense, using suggestion to turn them into a toad not so much). The one the inflicts poison is even named "Hypochondria".
- There's a variant in Fallout 2 wherein you can trick a slavemaster into thinking one of his slaves has a disease (made-up and named after your character.) Symptoms include shiftlessness and unwillingness to follow orders. It's highly contagious, so he'd better hand that slave over to you before it contaminates the rest. The same can also be done while bartering for some slaves (to free them of course!) in Fallout: New Vegas.
- One puzzle in Strong Bad's Cool Game for Attractive People: Strong Badia the Free involves convincing Strong Sad that he has "acute aphasic pretendicitis". Symptoms include uncontrollable shaking, a high fever, and inability to comprehend spoken language (achieved by clever use of a malfunctioning toy, application of a lighter to Strong Sad's thermometer, and attempting to communicate with Homsar, respectively).
- In Dragon Age: Origins, one of the Crime Spree sidequests is to get the jeweled sword from a lady knight who's currently shopping. You can opt for just a straight pickpocketing if your skill is high enough, or you can bluff her into thinking she's got a potentially deadly disease that will kill her if she's wearing too much clothing and not breathing hard enough, causing her to strip down to her underwear and hyperventilate until she passes out right in the store.
- In Stand Still, Stay Silent, when Emil finds a bruise in his face and asks Mikkel if there's risk of scarring, Mikkel has some fun telling him that face-bruises can turn cancerous if not properly bandaged. Made even funnier when Emil then tells Admiral Olsen that his face is bandaged to prevent face-cancer, and Olsen recognizes that lie and starts looking around for Mikkel.
- The SCP Foundation has a rather odd example in SCP-1025, which causes hypochondria-by-proxy: others perceive anyone who reads it as contracting a number of dangerous diseases. It caused panic in several researchers before another Foundation agent took the book away and stuck it in a box where it can't affect anyone else.
- Bugs Bunny was fond of this trick, even to the extent of using spotted glasses to convince Elmer Fudd he was "seeing spots".
- "Hare Tonic" has Bugs convincing Elmer he has "Rabbititis", and does this by making him "see spots" by painting the entire living room and tricking him that he's turned into a rabbit by removing the mirror glass and mimicking Elmer's movements.
- In "Hare Trigger", Bugs convinces Yosemite Sam he's suffered a fatal head wound by pouring red ink on Sam's head. Sam even keels over and goes into "death throes" before he discovers the ruse.
- "Dr. Devil and Mr. Hare" consisted almost entirely of Bugs doing this to the Tasmanian Devil.
- The Looney Tunes cartoon "The Hypo-Chondri-Cat" takes this gag to its ultimate degree, as mice Hubie and Bertie eventually convince Claude cat that he's dead.
- In the DuckTales (1987) episode "The Money Vanishes", the Beagle Boys steal Gyro's latest invention by convincing him he has Inventoritis from being too sedentary, and needs to start jogging... right this instant. He jogs away and they have the run of the laboratory.
- In the Hey Arnold! episode "Monkey Business", Helga believes she has contracted "Monkeynucleosis" and will die from it after an organ grinder's monkey kisses her on the arm, which gets red, itchy, and puffy shortly after. The sweaty palms and loss of appetite were all in her head, and her irritability is common throughout the series due to her Tsundere tendencies toward Arnold. Phoebe confirms this, and that all Helga got was a rash on her arm from contact with the monkey. For bonus points, the ailment that Helga thought she had? She read about it in a book about medical hoaxes.
- In the Ed, Edd n Eddy episode "A Case of Ed", Edd convinces himself that he has a rare and deadly disease, and Eddy decides to take advantage of this for a few cheap laughs. Edd is not amused when he learns the truth.
- In one episode of Adventures of the Gummi Bears, Cubbi and Gusto end up captured by Toadwart and a pair of ogres. They convince the ogres that they have "gummioleosis", a highly-contagious disease. For added points, they give the ogres a "cure" that involves bathing (anathema to ogres) and scrubbing their chicken pox-like spots (paint) with "one small ogre"...and the two ogres run off chasing after Toadwart.
- In one Tom and Jerry short, Jerry painted spots on Tom to make him believe he had measles. Tom eventually finds out and goes after Jerry, but finds that now Jerry had the measles for real.
- In an episode of Help!...It's the Hair Bear Bunch!, the bears convinced the zookeeper, Mr. Peevly, that he had "zoo-lirium" and had to take a vacation from the Wonderland Zoo.
- Classic Disney Shorts brought us "Donald's Day Off", were Donald Duck's nephews prank him into thinking he's sick to the point of soon death. Made hilarious by how Donald is convinced of his "disease" to the point of ignoring logic and reason:
Donald: *walking with his eyes closed* I can't see! Oooow, ooooow! Oh me, oh my *Gets hit with a toy train* Ouch! *Opens his eyes, pushes the train out of the way, and keeps on being "blind"* OOOW, OOOOOW, OOOOOOOW! *Faints*
- In the House of Mouse short "Mickey's Remedy", Mickey Mouse tricks Don's nephews into thinking that they have "Bolvanian Brain Fever" to teach them a lesson after they've taken advantage of him by Playing Sick. He goes as far as convincing them that they have died, and will go to "the bad place" unless they redeem themselves: when Donald returns, he is shocked to find them perfectly well-behaved.
- In the The Simpsons episode "Little Big Mom", Lisa is angered by Bart and Homer's slovenliness and convinces them they have leprosy to teach them a lesson. It backfires big: when Lisa tries to convince them that the only cure for leprosy is to clean their home, they absolutely refuse and instead go ask Ned Flanders for help, and Ned sends them to a leprosy clinic in Hawaii, which is a very nice resort if not for the literally tortuous therapies.
- In the Spongebob Squarepants episode "Once Bitten", Patrick convinces Squidward that Squidward has Mad Snail Disease, kicking off a panic in all of Bikini Bottom. Slightly unusual example in that Patrick isn't trying to get rid of Squidward; mostly he seems to enjoy the attention and the fact that people listen to him and treat him like an expert.
- Another episode has Squidward getting annoyed by SpongeBob constantly laughing and convinces him that he has a disease where if he doesn't go 24 hours without laughing, his "laugh box" will break and he will never be able to laugh again. Inverted in the end when the disease turns out to be real and it happens to Squidward. Luckily, SpongeBob donates part of his laugh box to Squidward.
- Another episode has Squidward trick SpongeBob that he (Squidward) has contracted "Squid's Disease" in order to get SpongeBob and Mr. Krabs to think he should go home sick. SpongeBob, however, being paranoid, begins to believe that he caught it.
- In the Total Drama Action episode "One Flew Over The Cuckoos", Chris convinces the campers that they are all expiring from a fatal disease during a medical-themed challenge by forcing them to spend all night reading a medical book and putting itching powder and laxatives in their pizza. Duncan and Leshawlna are the only ones who aren't fooled because they didn't study and eventually expose the illusion to the falsley diagnosed campers.
- In the South Park episode "Bloody Mary," Randy Marsh drives drunk and gets pulled over and prosecuted for a DUI offense. Part of Randy Marsh's sentence for his DUI is enrollment with Alcoholics Anonymous and their twelve-step program. At first, he is only willing to confess that he "really like[s] beer," but the AA members not only push him to say that he is an alcoholic, but Randy begins to compulsively drink alcoholic beverages, convinced that he is an alcoholic. Hilarity Ensues after this, culminating in Stan convincing Randy that he is indeed able to control his alcohol consumption, restoring the status quo.