At its simplest, this trope is when a character accidentally tells another character something that they didn't know because the former was under the impression that the latter already knew.
This trope can occur in the following ways:
- Alice accuses Bob of something (eg. "You were trying to steal a cookie from the cookie jar because mom got a spa coupon and you knew she would be out!") and have it backfire on her because it turns out Bob had no idea up until that point (eg. "Wait, mom's not home? Well, perfect time for me to go raid the jar!")
- A similar version to the above is when Alice invokes this trope and accuses Bob of something...literally, as in she's being vague and making it seem like she knew the whole story already (eg. "I know what you did!"), so Bob assumes she does and asks, usually something like "How did you know I stole a cookie from the cookie jar?"
- There's something that Bob doesn't know, or is not supposed to know, however Alice either doesn't realise it or thought that Bob had managed to find out and thus talks to Bob about it, with all the irony involved (eg. "You should get a pint of milk for that box of cookies Charlie gave you for your birthday." "Wait, Charlie's giving me a box of cookies?") This may lead to an Internal Reveal.
Subtrope of Saying Too Much. Sister trope to You Know What You Did, You Didn't Ask and You Just Told Me. Often results in Nice Job Breaking It, Hero! or Nice Job Fixing It, Villain!. Compare and contrast I'll Never Tell You What I'm Telling You!. See also Everybody Knew Already and Poor Communication Kills.
- In Inazuma Eleven: Ares, before Inakuni Raimon's match against Tonegawa Tousen, Anna tried to talk to Nishikage about Nosaka's brain tumour, assuming Nosaka already told his friend about his ilness. Nishikage became angry that he wasn't told.
- Dungeon Keeper Ami: Multiple times. Done by and to Ami:
- In "Deadline", the Avatar reveals him being attacked through his mantle this way:
"What is it Mercury? Have you come to gloat about finding a way to attack me through the Mantle?"
"I'm sorry. Please believe me, this is the first I learned of your sickness. The mantle was stolen from me, and I was going to ask for your help to get it back! I didn't even know it could be used to harm you," she blurted out.
- From "Diplomacy and Gifts":
"Disappeared?" Ami sat up in surprise. "Could you clarify, please?"
Durval tilted his head to the side in surprise. "The period during and after the battle in which you were hidden from scrying detection," he elaborated.
Up until this point, Ami hadn't even considered the possibility that getting possessed would interfere with scrying methods. She still existed, after all. She blinked twice while her mind raced, considered the implications. "This is news to me," she admitted.
- In "Deadline", the Avatar reveals him being attacked through his mantle this way:
- The Incredibles: After making a new suit for Bob, Edna makes suits for the whole Parr family and shows them to Helen, inadvertently revealing to her that Bob has been doing superhero work behind her back. Edna says "I already thought you know. Why would he keep secrets from you?"
- In Passengers (2016) Jim, Aurora, and Arthur were chatting when Jim states that there are no secrets between him and Aurora. Arthur unfortunately mistook this to mean that Aurora knew Jim woke her from cryosleep and talks to her about it, which is how she (ironically) finds out.
- In American Gods as well as its adaptation, American Gods (2017), Shadow finds Audrey's behaviour at Laura's funeral weird. When asked about it, Audrey says: "Well I thought that would be obvious. Wait... you didn't know? Your wife died with my husband's cock in her mouth." Doubles as Everybody Knew Already, as Shadow was in prison while the affair lasted and their common friends and acquaintances did know.
- Five Find-Outers: The fourth book "The Mystery of the Spiteful Letters" has the protagonists find their friend Gladys has gone, however their parents remained elusive as to the details. Fatty decides to visit Mr. Goon and via acting like he knew the whole thing already, got Goon to reveal that Gladys had received a letter about her Dark and Troubled Past.
- The Jigsaw Jones series featured a mystery where a character leaves behind vague messages that they "knew what they did" in Cut And Paste Notes. In the end it's revealed the perpetrator didn't know a thing and was conducting an experiment to find out if people would be nicer if they thought they were constantly being watched (the answer was yes).
- In the Warrior Cats book Forest of Secrets, Fireheart knows that his nephew Cloudkit is going to face prejudice due to having been born as a house cat, and begins to give him a lecture about this, only to realize that Cloudkit's foster mother hadn't yet told him about where he was born. Needless to say, it's a bit of a shock to the young kit.
- In The Thrawn Trilogy of the old Star Wars Legends continuity, this is Played for Drama. Mara Jade, a Force-using ex-Imperial with an imprinted command from the Emperor that "YOU WILL KILL LUKE SKYWALKER," has fallen in with a group of Noghri, assassin aliens who remain with the Empire due to their loyalty to Darth Vader, and who are now happy to be serving the "Son of Vader." Mara has no idea, until one of them tells her, who that Son of Vader is... and when she finds out, it puts an entirely different spin on the Emperor's last command.
- In the Discworld novel Men at Arms, we first see that (then) Corporal Carrot Ironfoundersson uses version 2 to amazing effect. Despite being under direct orders to leave peacefully and without protest, should the Fools' Guildmaster (Dr. Whiteface) refuse to answer his questions, Carrot manages to convince Dr. Whiteface that, not only is it in the Guildmaster's interests to answer Carrot's questions, but that the watch already knows what the Fools' Guild is hiding. note This turns out to be one of Carrot's favorite interrogation methods. Granted, Carrot had very good deductive suspicions, but no actual knowledge of what was being hidden.
- In the Bones episode "The Death of the Queen Bee", Hodgins is chatting to Wendell (who's seeing Angela) and happens to mention Angela's pregnancy scare ("The Proof in the Pudding")... only to look at Wendell's face and realize this is news to him. Hodgins runs off and manages to find her in time for a hurried apology/warning before Wendell catches up. Discussing the hypothetical baby and how things would have played out leads to Angela and Wendell becoming Amicable Exes.
- Burn Notice: As a former government spy, Michael is skilled at tricking people into revealing their secrets this way. One of his common tactics was to make vague statements about his target's businesses or illicit activities and then let their minds do the rest of the work, assuming that Michael must know more than he actually does. He can also do this in reverse, tricking two targets into betraying each other by telling them information he "Thought they already knew" (but is actually a complete lie) which makes Target A think they've been betrayed by Target B.
- In the first episode of Everything's Gonna Be Okay, Matilda accidentally tells Genevieve's friends that Genevieve just had her first period, not realizing that Genevieve has been lying to her friends about having periods for the past two years.
- The Frasier Christmas Episode from Roz's pregnancy has the title character answer Roz's cell phone while she's in the toilet. It turns out to be Roz's mother and Frasier tells her a few things including that Roz is having some issues with her pregnancy. After Frasier hangs up, Roz returns and he tells her about the phone call. She tells him she hasn't told her mother about her pregnancy yet and can't wait to tell her.
- On the Friends episode "The One Where Ross Is Fine", Chandler and Monica are visiting a couple with an adopted child. Chandler mentions the adoption to the child, Owen, who didn't know he was adopted. Later, Chandler makes a joke to Phoebe about telling Frank Jr's triplets that Phoebe carried them - right in front of them.
- In the Law & Order: Special Victims Unit episode "Fallacy," Stabler says to the suspect's boyfriend it's okay what his sexuality is and he doesn't get what he's telling him until he gets the Unsettling Gender Reveal that his girlfriend is a transgender woman.
- Schitt's Creek: David invites Patrick's parents to a Surprise Party for Patrick's birthday, assuming they know that Patrick is gay and that they are boyfriends as well as business partners. Johnny naturally assumes this as well so when he welcomes Patrick's parents to the motel, he refers to David and Patrick's romantic relationship, leading to a Forced Out of the Closet moment for Patrick.
- When Tahani brings up she has never heard Jason talk about his father in The Good Place, Jason responds that he thought he did mention Donkey Doug a few times, which he did, but considering he calls him "Donkey Doug" it wasn't clear to everyone he was talking about his father.
- Alpha Protocol: Steven Heck somewhat offhandedly mentions he knew Scarlet was the assassin at Taipei after he blows her in half with a shotgun blast during the final mission; when Mike asks for clarification, Heck just mentions he thought Mike knew it all along and was just letting it slide for a chance to bed her.
Heck: "Pretty classy", I thought.
- This is how Tidus finds out Yuna will die at the end of her pilgrimage in Final Fantasy X.
- Khaos Komix: Unknown to her, Charlie is outed as Transgender to her boyfriend Jamie when her mother talks to him about her past Trans Tribulations. Played for Drama as he acts as Secret Secret-Keeper for most of a chapter while Charlie struggles with how to come out to him.
- In Poppy O'Possum Magi Lila Moon accidentally let slip to Friedrich that there were still gods active on Flora because she forgot his clearance level. Forcing her to erase his memory of the last minute.
- Bob's Burgers: "Turkey in a Can" involves the Belchers trying to solve a mystery of who keeps shoving the turkey into the toilet. Louise accuses Gene and Tina of doing it to frame her in revenge for her siphoning from their allowance for the past 5 years, only for Gene and Tina to state that they had no idea she was stealing.
- The Fairly OddParents!: Cosmo and Wanda have a baby in "Fairly OddBaby". Fairy babies are supremely powerful to the point where having new babies was banned (or at least it should — unfortunately they forgot to actually write it down in the rulebook), so the fairies are understandably concerned when the baby goes missing. They barge into both the Anti-Fairy World and Pixie World accusing them of kidnapping the baby, however it turned out neither of their suspects even knew that the fairies had a new baby.
- King of the Hill: It's an extremely obvious Open Secret that Nancy Gribble is cheating on her husband Dale with John Redcorn, which led to the birth of Joseph. As it turns out, Peggy legitimately didn't know about this until over a decade after Joseph was born, and only after Hank all but flat-out told her when he realized her obliviousness to the fact. When Peggy demands to know why Hank never said anything about it before, he admits that he thought she knew already, since everyone who knows the Gribble family is aware of it (except, ironically, for Dale himself).
- Rocko's Modern Life: In "Who's for Dinner?", Heffer invites Rocko to have dinner with his family, who turn out to be wolves. While at the table, he mentions that Heffer never told him he was adopted, to which Heffer reacts with shock, as he didn't know either.
- In Sonic Underground, the Oracle tells the Queen the prophecy of Robotnik's rise and eventual fall thanks to her and her children. He then proceeds to use this knowledge as Unsportsmanlike Gloating against Robotnik, thus alerting him the threat's existence in the first place and motivating him to actively seeking them out.
- SpongeBob SquarePants: In the episode "Enemy In-Law", Plankton falls in love with Mr. Krabs's mother and plans to marry her. Mr. Krabs assumes it's a scam to get the Krabby Patty formula out of his mother, who also knows it. Turns out Plankton was genuinely interested in her and didn't know that Mrs. Krabs knew the secret formula... until Mr. Krabs told him. Then Plankton realized that now he could use his upcoming marriage to her to get her to give him the formula. However, she breaks off the engagement before it can happen.
- OK K.O.! Let's Be Heroes: In the episode "Big Reveal", KO asks his mother who his father is. She casually responds "Laserblast". Cue Spit Take.