I Never Told You My Name

Alice has just met a man named Bob, who seems like a perfectly nice person-- until he uses her name. To which Alice realizes and possibly responds, "I never told you my name."

This trope is used to place suspicion on an otherwise ordinary character or to hint that there is more to the character than meets the eye. The person whose name is used does not necessarily have to notice; it could simply be a hint to the audience to pay more attention to the character who knew it without being told.

It can also be used humorously, generally with subversions, such as Alice asking why Bob knows her name... and Bob revealing that Alice was wearing a nametag the whole time. This is also easily double subverted, if the nametag doesn't reveal the full name, although that tends to be in less humorous situations.

Compare I Never Said It Was Poison, where a suspect incriminates himself by revealing confidential evidence only the person involved in the crime would know, and Spotting the Thread, where the spy is an impostor imitating someone Alice knows, instead of acting as a new person.

Anime and Manga

 * In Needless, Mio sneaks her way into Cruz's team. Though he doesn't find out for sure she's a mole until Mio turns on them, Cruz quickly becomes suspicious of her when she calls him "Cruz" as opposed to "Yamada" (his nickname, which everyone in the team uses instead of his real name).
 * A variant in Monster: Tenma realizes that a couple of policemen aren't what they seem when they address him as "Dr. Tenma" after he only told them his name and not that he was a doctor.
 * In JoJo's Bizarre Adventure, Enya Gail, one of Dio's most loyal followers, pretends to be an innkeeper in order to lure Jotaro and company in to be killed by the effect of her Stand, Justice. However, she inadvertently gives herself away by addressing Jotaro by his correct name, when in fact he had registered to the inn under a false name.
 * In the Hoshiyomi filler arc of Inuyasha, demons manage to get a photo of three of Kagome's friends from her backpack, and use it to create puppets of them in order to trick Kagome and Hojo into handing over the magic blade that their master needs. Kagome is suspicious to begin with, but her suspicions are confirmed when one of the three calls her by her name - which she hadn't mentioned to them.

Comicbooks

 * In an issue of Justice League of America, Plastic Man in disguise was talking with Bruce Wayne and after a while, Bruce said his name. Plastic Man never mentioned his name and he and the group chased him and "Bruce" was revealed to be a telepathic alien with amnesia.
 * Subverted in the miniseries Oracle: The Cure: Barbara never told Corey her name, but when she pointed this out, he reminded her that he had known her when he was a kid from her librarian days.
 * A variation shows up Irredeemable, when the Plutonian refers to the Hornet's wife by name during a Flash Back. The Hornet had never mentioned her name to him, and realizes that he's spying on his teammates and may not be entirely trustworthy.
 * In Usagi Yojimbo, Sasuke does this to Usagi, Jotaro, and probably everyone else he meets. When someone calls him on it, he just dismisses it - "You must have mentioned it earlier." In this particular case, it's because Sasuke is a powerfull spellcaster and can read people's minds.

Fan Fiction

 * In Turnabout Storm, shortly after Twilight Sparkle accidentally summons Phoenix Wright to their world, she addresses Phoenix by his name before he properly introduces himself to her. When he calls her out on it she hastily claims that she had a NameDar spell performed on him when he arrived. Though it sounds plausible enough, some of her future actions still make clear that something's up.
 * In the Harry Potter fic "Make a Wish", the auror interviewing Harry after he killed an assassin with accidental magic referred to him by his assumed name of "Mr. Black" despite the lack of an introduction. Harry commented afterwards to another auror on the team that "His technique was so calm and relaxed that I don't even remember telling him my name."

Films - Live-Action
"Domino: My my, what sharp eyes you have.
 * In The Truman Show, Truman's attempt to drive out of town with his wife ended when an unknown cop told them the road was closed. However, the cop then addressed Truman by name without ever being told his name or shown any ID. This immediately lets Truman know something is up.
 * In The Sorcerers Apprentice, Nicolas Cage's character does this to the young Dave. When Dave asks how he knows his name, Cage bursts out, "Because I can read minds!" After a Beat, he says normally, "It's on your backpack".
 * A variation occurs in City of Angels. Seth calls Maggie by name and when asked points out that she's wearing a nametag. Later, she pulls off the nametag and it only shows her last name.
 * Played with in an uncharacteristically subtle moment early on in Red Eye, in which the villain ends up saying the name of the heroine's father in conversation with her and she doesn't notice that he'd just said a name she'd never told him. Probably a good many people in the audience didn't either.
 * In The Rich Man's Wife, Josie (the wife in question) is being terrorized by her husband's killer, who is demanding an exorbitant sum of money from her and threatening to tell the police that she hired him to kill her husband (she didn't). She goes running to her ex-lover Jake, pleading for his help. He calms her down, assuring her that "Cole won't hurt you." She's grateful, until she suddenly realizes that she never told him the man's name -Jake hired the man to kill her husband so that Josie would come back to him.
 * Possibly subverted in Thunderball when the Bond girl Domino demands to know how Bond knew that was her name (or rather, her nickname); he says it on the bracelet on her ankle. The "possible" part is that its not clear he hasn't read up on her already, since the reason he is in the Bahamas is following a lead about her recently murdered brother, though it didn't lead to her directly.

Bond: (as she walks away) Wait till you get to my teeth."


 * In The Prophecy, Gabriel confronts Thomas as he's sitting in church. When Thomas questions how Gabriel knows his name, Gabriel dismissively tells him "You look like a Thomas."

Literature

 * There's a variation in the mystery novel Say It With Bullets by Richard Powell. The hero is talking to a woman he has just met when she reveals she knows exactly when his birthday is. He is immediately suspicious of her, but it turns out she had met him and had a crush on him when he was 16 and she was 12.
 * In Carpe Jugulum when Agnes meets Vlad he says her name without being told. When she considers that he might have asked someone Perdita asks her why anyone would ask for her name.
 * Played with a little in one of the books of The Riftwar Cycle. Erik von Darkmoor is approached by a friendly man, whom he has never met, but who calls him Erik. When the man switches to calling him "von Darkmoor" instead, Erik's squadmates stick a knife in his back. When Erik asks how they knew this man was up to no good, the squadmate says that the man might have overheard "Erik" somewhere, but everyone was under strict orders not to use the name "von Darkmoor".
 * In the Children of the Red King series, Alice Angel knows Olivia's name immediately when she and Charlie walk into her shop, and uses it repeatedly. It doesn't say much for Charlie's character that he doesn't think anything is wrong until Alice also says his name. It turns out that, unknown to them  and.
 * Artemis Fowl: When Artemis first kidnaps Holly, he calls her "Captain Short". When she demands to know how he knew her name and rank, he points out that she's wearing a name tag... except, as Holly next points out, the name tag is written in the fairy alphabet, which Artemis shouldn't be able to read. (As it happens, Artemis had stolen a copy of the fairy Book and deciphered their language.)
 * Invoked Trope since Artemis did this on purpose, knowing she'd notice the "slip" -- and that she would understand the significance of how he knew.
 * A variation occurs in Nuklear Age when Superion mentions the name of Atomik Lad's girlfriend to him, when Atomic Lad had been careful not to mention her name around Superion because he already distrusted him; this incident only heightens that distrust.
 * Occurs in the Ciaphas Cain short story Sector 13. Cain identifies a Genestealer hybrid when it refers to him by name before he introduces himself; he'd told his name to another hybrid, and 'stealers communicate telepathically.
 * In the YA novel The Third Eye, clairvoyant protagonist Karen is walking to her job at a day care center when a woman stops to offer her a ride, saying that she's affiliated with the same center and recognizes Karen. It isn't until the woman addresses her by her name, which she hadn't mentioned, that Karen realizes she's being kidnapped.
 * Similar to the double-subversion example at the top, in Wizards's First Rule, Richard realizes that a person is actually a shapeshifter when they only know Zedd by his nickname, which Richard mentioned. Richard challenges it to say Zedd's full name, it realizes the game is up and attacks, and Richard fights it off.

Live-Action TV
"Agent 1: Can you tell us where she [Daisy] is, Mr. Topp?
 * Spaced played with this in their Homage (of sorts) to The Matrix. With the agents grilling Brian at the front door when they were looking for Daisy.

Brian: How do you know my name?

Agent 1: It's written on the doorbell.

Brian: ...All right.

Agent 2: Where is she, Brian?

Brian: ..."Brian" isn't on the doorbell."


 * In the Firefly episode "Trash", Mal is introduced to a pilot friend's new wife- who is a con artist that Mal has previously had a rather severe run-in with. They commence fighting, and the pilot demands to know what's going on. Mal shouts accusations at her, to which she responds "You're a liar, Malcolm Reynolds!" The pilot had never told her Mal's full name.
 * One episode of NCIS features a variation. A potential love interest of visits him at work ... except he never told her he was with NCIS.
 * On one episode of The X Files a character gives himself away with this trope but he's talking so fast that the audience might not notice until Mulder stops him, saying, "Whoa, whoa, wait a minute here...When did I say my name was 'Agent Mulder'?"
 * In the Stargate SG-1 episode "Window of Opportunity", Jack realizes that Malakai is also in the time loop when he uses Carter's name, despite not having been introduced to her in the current loop.
 * A variant occurs at the tail end of the Castle episode "Sucker Punch".
 * In Battlestar Galactica Reimagined, Kara "Starbuck" Thrace realises that Simon knows more than he should when he calls her Starbuck - she had only told him her real name, not her call sign. It doesn't end well for Simon (though being a Cylon, He Gets Better).

Radio
"Pip: Whackwallop? Then you are a cousin to the Sternbeaters and Hardthrashers, and a natural ally of Mr Benevolent!
 * A variation gets spoofed in Bleak Expectations:

Dr Whackwallop: Gently who?

Pip: I am completely reassured."

Theatre
"Siegfried: You called me Siegfried. Did you ever see me?
 * In Götterdämmerung by Richard Wagner, Siegfried is a bit suspicious when scheming Hagen calls him over as he rows past the Gibichungs' castle. Unfortunately not suspicious enough...

Hagen: I recognized you only by your strength."

Videogames

 * In Silent Hill 2, Maria calls James by name in spite of the fact that he never introduces himself. James never comments on this or responds to it in any way, and it's far from the only knowledge she should not have and yet does.
 * In the English version of The World Ends With You, upon meeting Neku, Joshua uses Neku's name twice before actually being told by Neku himself. Used to hint that Joshua is more than he seems, as he later ends up being a very significant character.
 * Iris does it to Phoenix in the last case of Phoenix Wright Ace Attorney. When Iris is confronted about it, five psyche-locks (which indicate secrets, number indicating how deep the secret is) appear before her and the issue has to be dropped. It's not revealed completely until the end. (Worth noting: the only other person in the series with five psyche-locks is someone covering up a massive conspiracy involving murder.)

Webcomics

 * El Goonish Shive, Painted Black arc. After Elliot is captured, he refers to Guineas by name. Guineas then tells Hedge that Elliot knew his name even though he hadn't been told it. This causes Hedge to realize that Elliot must know Grace, who alone could have told him.
 * Appears in Questionable Content.
 * Namir Deiter, after a convention.
 * In General Protection Fault, Trish, upon meeting Jason "Fooker" Barker for the first time, casually mentions that she once knew a Barker. Fooker is a bit suspicious that she knew his name when no one mentioned it before, and she most likely knew because.

Western Animation
"Woman: I've been waiting for you, Lisa.
 * Occurs in the Simpsons episode "Lisa's Wedding", where she's talking to a fortune teller at a Renaissance Faire:

Lisa: * GASP * How did you know my name?

Woman: Your nametag."