Totally Not a Spy

This is where a character, usually a spy, will explain the dangers posed by a specific individual being among the group. He will often go into such detail that there's no doubt in the audience's mind who this person is, but most of the time the people he is addressing will be oblivious. In fact, the opposite will often occur where someone will exclaim that he knows everyone and there's no possible way it could be any of them.

Often used by a Villain to invoke Spot the Impostor to create paranoia, gain a character's trust or both. Not to be confused with Most Definitely Not a Villain as this ruse is generally well thought out and only Genre Savvy allows the audience to see through it.

Comic Books

 * Guy MacGuffin does this is in Spy Boy.

Film

 * Used in Breach when Robert Hanssen, based on the real life FBI agent convicted of being a Soviet spy, who is part of the team looking for The Mole. A bit of Truth in Television as the real Hanssen hacked into a fellow agent's computer and produced secret files which he presents to the person whose computer he hacked. It was later theorized that Hanssen did this to cover his tracks when he hacked the computer to see whether he was suspected as a spy.

Literature

 * In the books of The Witcher series a vampire participated in a small talk about vampires. He even recommended some "folk remedies". Including garlic (which he ate at the moment). Of course, in his case it was more fun than precaution: greater vampires of that world are Nigh Invulnerable and before this incident he once was dismembered and buried in several places for a few years, then "got better" anyway.

Live Action TV

 * Burn Notice: In one episode Michael Weston is doing some spy-hunting for a client until he realized the client was a bad guy. So he decides to become the actual mole, and then keeps the client's paranoia high by telling him all the things the spy could do to him.
 * Another time Jessie works as a security consultant for a Corrupt Corporate Executive CEO. He calls the security guards at the gate to him so he can explain to them how their lousy security measures can just allow anyone to walk in through the gate. Cue Michael walking in through the gate as the guards are looking at Jessie. The entire scheme centers around Jessie constantly warning the CEO about how bad his security is specifically so Michael has an easier time penetrating that security.
 * The Whitest Kids U Know: In the sketch "It's Illegal to Say", this trope is invoked. It quickly becomes clear that the message telling the audience that it's illegal to say you want to kill the President is a cover for describing a plan to kill the President with a mortar launcher.

Video Games

 * In the "Meet The Spy" video for Team Fortress 2. The BLU Soldier figures from the BLU Spy's speech that the BLU Spy is actually the infiltrating RED Spy. Except...
 * Wait, wasn't that video around the time of the introduction of the Dead Ringer watch? The thing that lets you pretend somebody killed you while you move off camera and start silently taking people out, starting with the one nobody's watching?

Real Life

 * "...I know how it works!"