What happens when a character realizes that the incredibly absurd story he's just been told has to be true — for the simple reason that no one in his right mind would claim such a ridiculous story unless it were true.
After all, think about it. What happens to someone in movie-land who claims that aliens are taking over people's bodies and passing themselves off as the originals to act as a prelude to an alien invasion? Loony. And then, of course, the aliens come and kill us all. So considering the risk and reward of making an outrageous claim, why would anyone in his right mind say such a thing unless he had good reason to believe it? This doesn't even get into the fact that if someone is trying to manipulate you with lies, it is obviously in their best interest to come up with more plausible ones.
Compare So Crazy, It Must Be True. Contrast Cassandra Truth, in which authority figures refuse to believe an implausible tale, and Sarcastic Confession, in which a character deliberately tells the truth in a way which won't be believed. A subsection of Refuge in Audacity.
- In Death Note when Mello tells Near about the killing notebook and the shinigami, the SPK asks Near if he could really believe such a story and he says that if Mello were lying to them he wouldn't tell such a ridiculous story so it must be true.
- In Watchmen, Rorschach's reaction to Moloch's story about the Comedian breaking into his room to sob about Ozymandias' plan is, "Sounds unbelievable. Probably true."
- In Batman, Alfred uses this to explain Bruce Wayne's injuries he incurs as the Batman. In one instance he claims that Bruce was injured by "falling out of a hot air balloon onto a table of cheese blintzes" because the story was "too ridiculous to be disbelieved."
- At the end of Superior Spider-Man, Peter gives Miguel / Spider-Man 2099 a rushed explanation of Dr Octopus's Grand Theft Me. Miguel goes from ready to attack Peter to totally accepting. "Yeah, that sounds JUST stupid enough to be right."
- In Atomic Robo, Carl Sagan provisionally accepts Robo's claims regarding an Eldritch Abomination because they were so audacious they piqued his curiosity.
- In the Worm fanfic Security!, Mrs Knott has gotten rather close to the self-insert protagonist Mike Allen. When he tells her the true story of his origins - that he's a fanfiction writer who somehow fell into the story - she decides to believe him, because he has no reason to lie to her.
- In The Dark Lords Ascendant, this is the reason why Sailor Pluto believed Ryouga when he told her the truth about the Dark Lords. In her mind, the entire scheme they cooked up to deal with the Senshi and the Dark Kingdom was too ridiculous to be considered a lie.
- A rather innocuous example in Ghostbusters (1984):
Egon: She's telling the truth; at least she thinks she is.
Dana: Well, of course I'm telling the truth! Well, who would make up a story like that?
Venkman: Some are people who just want attention. Others, just nutballs who come in off the street.
- She is telling the truth, of course, and they do take her story seriously (well, except for Venkman, who just pretends to so as to get in her pants).
- Played with in Penn & Teller's movie Invisible Thread. Aliens plan to destroy the human race because there is nothing unique about us. Penn demonstrates Earth's uniqueness by claiming we've invented invisible thread, and goes on to perform a simple magic trick. The aliens decide immediately to leave the world alone. The kicker is that they privately inform Penn that humanity's uniqueness wasn't the trick, but rather our capacity for utterly ludicrous lies.
- A memorable scene in Charade involves the male and female leads claiming to a police officer they had not committed a murder the previous night, but each only offering the alibi that they had been in bed, alone, in their own hotel room. The officer quipped: "Clearly you must be telling the truth-" significant glance at the obviously-falling-in-love couple - "for why would you invent such a ridiculous story?"
- In Stargate Continuum, after he, Sam, and Mitchell have tried for some time to convince people they're in an alternate reality, Daniel gets frustrated and snaps, "Seriously, who would make this shit up?!"
- The Chronicles of Narnia: In The Lion, the Witch, and the Wardrobe, Professor Kirke uses this as the reason for why he believes Lucy's story about the wardrobe - if she had been lying she would have hidden for long enough that people started looking. (There's also the fact that he's been there himself, but C. S. Lewis hadn't thought that part up yet).
- Seen in Doom. Albert believes that Fly and Arlene aren't enemy spies because their story of riding Deimos to earth, defeating that wing of the invasion, and building a rocket to crash on earth is too ridiculous to be an effective lie. Lampshaded by Fly, who thinks that spies should be telling absurd stories if that's the trick to trust.
- In the Sherlock Holmes story "The Boscombe Valley Mystery", this is what leads Holmes to believe that the young man who has been arrested may be innocent after all — the statement he gave the police is too stupid to be a lie. Played with, in that Holmes himself argues that the police (and Watson) are in fact simultaneously crediting the man with lying too much and too little, in that his story contains several outlandish details that the police would outright disbelieve and / or work to incriminate him while not containing enough details that might exonerate or excuse him. A man who was definitely lying would be certain to try and include more of the latter and less of the former.
- In A Song of Ice and Fire, this is how Brienne manages to convince several people that she was not the one who killed King Renly despite being one of the only people in the room with him when he died. If she were the culprit, wouldn't she come up with a better story than "evil demonic shadow did it?"
- Arthur C. Clarke's Tales from the White Hart series of short stories concerns a "scientist", Harry Purvis, who tells scientific tall tales at a London pub called the White Hart. His outrageous stories' scientific logic is often called into question, but he is kept around for entertainment's sake. The exception is one story, "What Goes Up", totally made up to deal with an annoying conspiracy theorist. The end reveals Harry's obvious bullshit is taken totally seriously by the conspiracy theorist, and poor Harry gets bombarded with mail by other nutjobs-turned-fans. In other words, the one story he never wanted anyone to believe was the only one people actually believed.
- Tamora Pierce's Tortall Universe: In Trickster's Queen, Aly explains to her friends that she wasn't there to stop Sarai from eloping because she was being held captive by a god. She points out that, since she's a spymaster, "You forget I like to tell lies that will be believed."
- In the first book of The Wheel of Time, Queen Morgase chooses to believe Rand's story because it is simply too absurd to be a lie. She notes at the same time that a clever liar would take advantage of this trope, but decides not to act on that impression.
- On The Brady Bunch, Jan gets a locket as an anonymous gift; it came with a typewritten letter where the "e" is slightly off. Carol and Alice sneak into Mike's office to test his typewriter, only to get caught by the security guard. They explain the situation to him and he lets him go, concluding that no thief would make up that kind of story.
- Doctor Who:
- In "The Myth Makers", with no other options, and facing death, the Doctor and Steven tell Odysseus the truth of who they are and how they came to be on the plains outside of Troy. Odysseus decides that the story strains his credulity beyond anything he's ever heard, and therefore it's probably true or they would never have dared to tell it.
- In "The Sontaran Experiment", the Doctor has transmatted to Earth from the lost space station Nerva, and some stranded spacemen accuse him of abducting their crew-mates, and insist that Nerva is just a legend. But one of them begins to think the Doctor might be telling the truth because "It's such a crazy story": if he was lying, he'd have thought of something better.
- In The IT Crowd, Roy's girlfriend tells him a ridiculous, incomprehensible story about the death of her parents. When Jen asks if she could have been lying, Roy answers, "Why would she lie? And if she was going to lie, why would she use this one? A fire at a Sea Parks?! It's wrecking my head! I mean if...if she had said that her parents had drowned, I'd be the happiest man in the world!"
- An episode of Jonathan Creek has Jonathan defending the accused in this episode mostly due to this trope. The man is accused of kidnapping a young girl who was seen entering his house by several witnesses. His defence is that he was in that room staring at the door the entire day (after being robbed and tied up in the room) and didn't see anyone come in. Jonathan points out that this is such an incredibly stupid defence that he can't possibly be making it up. Of course, he's right. The truth is that after being knocked out during the robbery, he was taken to a nearby farm where a cult had recreated the interior of his room so he thought he was in it all day (later knocking him out and taking him back as he slept) so they could kidnap the girl and pin it on him, all in an attempt to get rid of the man's wife who had been critical of (and then stopped) his funding of the group.
- It's used again in the episode "Black Canary" when a man comes up with a seemingly impossible story about seeing his wife argue with an unknown man outside in the garden seconds before she shot herself - only for the man to leave no footprints in the snow. The police inspector on the case points out that the man is practically above suspicion - as why would he make up a story so impossible that no one would believe it?
- Similarly done on Spicks and Specks in "One Out of Three Ain't Bad". Adam tells a story with one true ending and two false endings. Played with when there are two equally far out endings, available and subverted when the team chooses the less implausible one.
- This has happened in Stargate SG-1 a number of times. For instance, when the team comes back from another world and Jonas Quinn tells General Hammond that there's a flying bug monster in the room that only he can see, Hammond immediately believes him and locks the base down because this is the kind of thing they often deal with. However, though the characters have experienced other weird things, which gives them a reason to accept new ones, they don't just accept weird stories because they're too crazy to make up.
- When an anomaly causes all parts of the ship in Star Trek: Voyager to shift into random time periods in the ship's history, Chakotay finally comes up with a solution. Unfortunately, putting the solution into action requires a deck currently under the control of Seska, Chakotay's old Love Interest turned villain. He reasons that the only way he can get her to cooperate is by being honest with her. While her subordinates are incredulous at the story, Seska declares it too implausible to be a lie.
- Subverted in the TV quiz show Talkin' 'bout Your Generation, host Shaun Micallef will often make a long, detailed, and ridiculous statement and then ask if it is true or false. The contestants often assume that such a statement must, by virtue of this trope, be true, only to have Micallef then tell them that they are wrong and he made the whole thing up.
- On To Tell the Truth, three people claim to be an individual with an unusual occupation/claim to fame, then answer questions from a celebrity panel who are trying to figure out which one is the genuine article. The celebrities often resort to this kind of reasoning, which can cut both ways. For example, one guest on the Garry Moore version was a single Vietnam G.I. who adopted two Vietnamese boys from an orphanage he'd volunteered in. One guest claimed to bring the boys along on dates, which struck at least one panelist as being so preposterous that it had to be true. (She was right.)
- Played straight, lampshaded, and subverted, in the comedy panel show Would I Lie to You? The premise of the show is that the two panellist teams must vote on whether the story/fact the member of the opposing team just read out about themselves is true or a lie. The stories often end up being ludicrous, and this trope is often played with, a lot of the time being played straight.
- It's lampshaded at one point.
David Mitchell: What I'm worried we're in danger of doing here is, having heard something that is absurd and obviously not true, and saying that therefore it must be true...
- In another episode David O'Doherty's claim was that he had made tiny leg warmers for birds, then went on to say that some of them were for swans. Despite how ridiculous and illogical everything sounded, Susan Calman said that she somehow thinks it could be true.
David Mitchell: Don't say that! Because that's what happens to your mind in this game. You say and you start to think, "the fact that he said swan and it seems impossible, is exactly what's so plausible about it"!
- It's lampshaded at one point.
- In Borderlands 2, the "Angel" the protagonists of both games have been taking instructions from reveals herself to have been working for Handsome Jack all along and betrays them. Afterwards, remorseful for her actions, she contacts them with advice on how to take Jack down. The Vault Hunters have no reason to trust her after everything that has occurred...except that her plan involves getting through a door that will destroy any tech not belonging to Jack's company, passing as Jack himself to both a DNA scanner and a voice analyser, and defeating an unstoppable robotic Bunker, not to mention the army of foes they'll have to fight their way through all the while. The heroes conclude that if Angel was laying a trap, she would have made success sound at least slightly plausible.
- This is what causes Sae Nijima to slowly start to believe the protagonist's account of the events leading up to his arrest in Persona 5. She notes that if he was going to lie, he could've come up with something far less insane that "we infiltrate a Mental World and reform criminals by literally stealing the physical embodiment of their desires."
- In Phoenix Wright: Ace Attorney - Justice for All, one testimony has a witness claim that they saw the defendant, a magician by the stage name "Maximillion Galactica", murder the victim then escape by flying into the sky. Although it's subverted in that Phoenix is the only one who actually believes the witness if the player picks the opinion to believe him. Although incidentally he wasn't actually lying. He just believed that what he saw was the murderer flying.
[Picking the "He's telling the truth" option]
Phoenix: What the witness just said was so bizarre, I don't think he'd have made it up.
Judge: S-So what he says is...true?!
Phoenix: T-That's what I think at least...
- Phoenix Wright: Ace Attorney - Trials and Tribulations has Larry Butz show his masterpiece drawing that he says is exactly what he saw at the time. The masterpiece shows a silhouette flying above a burning bridge. Nobody believes it's real... until Phoenix realizes during the second trial day that Larry's drawing is correct. Larry was lying on his back and looking up at the bridge, so what he actually saw was a body swinging underneath the bridge, but then drew the scene upside-down.
- One episode of King of the Hill sees Hank being accused of worker's compensation fraud. He can't sway the oversight board with his words, but eventually gets an idea and asks if he can call the yoga teacher who helped him as a witness. The teacher comes in and generally acts obnoxious, and Hank points out that he'd never spend any amount of time around a guy like that unless he absolutely had to — which is enough to convince the board of his honesty.
- Used in The Simpsons on a few occasions;
- When the town thought that Skinner and Ms. Krabappel were having sexual relations at school, Skinner cleared his name by telling them he was a virgin. This worked because, according to Superintendent Chalmers, no one, anywhere, ever, would ever pretend to be a 44-year-old virgin. The end implies that he was, in fact, lying.
- When Lisa discovers evidence that town founder Jebediah Springfield was actually ruthless pirate Hans Sprungfeld, the only person who believes her is Homer as he knew she wouldn't make up something like that.
- The "criterion of embarrassment" has an analogue in the common-law rules of evidence: the statement against interest and (in the context of the US) the opposing-party statement/admission. These are similar but different; in the statement against interest, anyone's words may be admitted, but they have to be unavailable (either because you can't find them, because they are dead, or because they are invoking a privilege) and they have to implicate the person in something that will cost them either money or jail time, while for an opposing party, you can only use the words of the other party to the case (e.g., in a civil lawsuit, the plaintiff can only use the defendant's words and vice-versa), but there are no other restrictions, the idea being that since the other guy is introducing them, they must be so bad for your cause that they have to be true.
- This trope is also the theory behind the propaganda technique known as the Big Lie. According to Hitler and Goebbels, if you are going to lie, don't say something that sounds like it might be true. Say something so outrageous that people will think that it must be true, because no one would make up a story like that.
- Doug Walker was trying to get into America after a con, and he'd lost his passport. After the border guard asked what his job was, and citing that he was essentially a comedian, asked Doug to tell him something funny. Doug responded by invoking this trope and explaining to the guard what a Brony is, citing things such as their tendency to welcome new fans with 'welcome to the herd'. It works.
- In an episode of Counter Monkey, Noah shares the tale of a D&D player he gamed with who never arrived on time, to the increasing frustration of his teammates. On one occasion he is two and a half hours late (despite living fifteen minutes away) and calls to explain that he was on his way but had to turn back because "I forgot my pants". Noah concludes that this must be the truth, because no one would make up such a dumb excuse, especially since the player was the one to call and had plenty of time to think up something better.