A type of messenger, the mysterious informant exists to feed information to the good guys, often just enough to keep them on track to expose The Conspiracy. The information is usually fragmentary and/or in cryptic Spy Speak. They tend to meet the main character in secluded areas like parking garages or shadowy alleys, be impossible to find unless they want to be found, always wear a Conspicuous Trenchcoat, and are usually masters of the Stealth Hi/Bye, to prevent heroes from pursuing them. He also insists that I Was Never Here.
In police shows, this role may be filled by a snitch. In shows involving conspiracies, the mysterious informant is usually an anonymous insider. In Speculative Fiction, this role is often filled by psychics and prophets.
The Trope Maker and a major inspiration for Stock Shout Outs is Deep Throat (decades later revealed to be W. Mark Felt, a deputy director of the FBI), the Washington Post's mysterious informant during the Watergate scandal that drove US President Richard Nixon out of office. The real-life Deep Throat, being Properly Paranoid, did in fact deliver vague, cryptic information in the dead of night in a parking garage and take other extreme precautions against being discovered.
Compare and contrast Mysterious Employer: he tells the characters what to do, but provides minimal information.
- The Big O anime: Big Ear, Roger Smith's information source. He's always in the same bar (in the same seat, no less) and almost never looks directly at Roger, reading the newspaper as they talk.
- Also, it's eventually revealed that he's an android.
- SSS ("Three Speed") from Madlax, the eponymous character's employer/contact who ends up selling out Madlax to Enfant under pressure. She doesn't hold a grudge at him for this.
- Sylia occasionally receives job offers and intelligence from one of these in Bubblegum Crisis. He spends at least half of each meeting hitting on her.
- Kujaku from RG Veda is one of very few people who knows what's going on with the prophecy, and the only one who helps the heroes.
- In Durarara!!, Izaya might not be nice or helping the good guys too often, but he is mostly definitely an informant.
- At Denpa Teki na Kanojo, Kid Detective Juu gets a phone call with only a word with a distorted voice saying park, the place where the Serial Killer would strike next. Subverted because the informant is really The Man Behind the Man trying to get Juu Lured into a Trap.
- Attack on Titan features a character known as "Owl" in Grisha Yeager's flashbacks. "Owl" is sending the Eldian Restoration Movement (which Grisha is the leader of) information to help them in their quest to restore the Eldia Empire to its former glory. This includes the supposedly true story of Ymir Fritz, the ancestor of the Eldians and creator of the Titans and getting Dina Fritz, the last remaining royal left on the continent (as opposed to the branch of the Fritz family that fled to Paradis Island). Grisha and Dina end up marrying and having a son named Zeke. Zeke was supposed to be Eldia's last hope, but he turned in his parents and other members of the Movement to the Marleyan military. The group are then sent to Paradis Island are are to be turned into mindless Titans. All of them are, except Grisha, who is saved by a soldier named Eren Kruger. Kruger reveals himself as "Owl" before turning into the Attack Titan and killing all the other military officials that were with him on Paradis Island. He then bequeaths the Attack Titan to Grisha and tells him to make it to Paradis Island's walled cities so that he can complete Kruger's ultimate goal of retrieving the Founding Titan. Essentially, he's responsible for setting a lot of the main events of the story in motion.
- In Hey Arnold! The Movie, there was a principal character who was impersonating "Deep Voice", a reference to "Deep Throat". This character also wore a trenchcoat and used a voice simulator. It was really Helga Pataki.
- Chatter Telephone from Toy Story 3 helped Woody out when things turned sour. He also has a kick-ass film noir voice.
- Donald Sutherland's character in JFK.
- All the President's Men has the original Deep Throat, Bob Woodward's government source who tells him to "follow the money."
- Hidden Agenda has Captain Harris, who claims to have been with British military intelligence and have information in the form of a tape recording that shows a conspiracy high in the government.
- In the Discworld novel The Truth, there is a mysterious informant known only to William De Worde as Deep Bone, who provides him some key information about the alleged attempted murder at the palace.
- Spoofed in the Beavis and Butt-Head book "The Butt-Files". In a section parodying The X-files, Beavis and Butt-head take the roles of Scully and Mulder, and get a tip from Deep Throat. Angered, Beavis yells "Dammit, you're always pulling this crap! If you know everything, why the hell don't you just tell us so we can go home! Now it's gonna take us another 45 minutes to figure this out!" Deep Throat initially refuses, but "Scully" persuades him with a kick to the crotch.
- Joe Grey in the Joe Grey Mysteries by Shirley Rousseau-Murphy. Since Joe, Dulcie, and Kit are, well, talking cats, they can't exactly walk into the police department to spill the beans on all they know.
- "Diana" in Boris Akunin's The State Counsellor leaks the terrorist organisation's secrets to the police - or is it the other way around? - and attains a considerable influence over the heads of several police departments. She really likes to keep up the mysterious appearance - it helps her maintain her Femme Fatale reputation as well.
- Those That Wake has the Librarian, who went off the grid shortly before Big Black.
- Police Squad! (the six-episode ABC series that later became the Naked Gun movies) also parodied this with Johnny the Shoeshine Boy, who knew everything if you had the price. After every visit by Frank Drebin, Johnny had to deal with a celebrity looking for advice or help on their special areas of expertise (Dick Clark asking about ska music, Dr. Joyce Brothers asking about psychology, and so on).
- The X-Files turned it into a cottage industry. Mulder's very first informant was Deep Throat, atoning for his deeds and helping Mulder's cause, (killed by The Men in Black in the season 1 finale); after him, there were the ex-MIB X (killed by another MIB in the season 4 pilot), Marita "SRSG" Covarrubias (infected with black oil in season 5, survived, and stopped helping Mulder), and the Well-Manicured Man (only in The Movie, killed himself with a car bomb).
- Malcolm in the Middle: When Hal is being indicted for his masterminding of a vast conspiracy to defraud the company he worked at, he's met by one of these at the public library who tells him that he's got six months to live and wants to die with a clean conscience. It's then neatly subverted when the informant turns up at court, testifies AGAINST Hal and says that the medical records were mixed up and he's going to be fine.
- An episode of Lois & Clark featured a constantly coughing informant called "Sore Throat". When Perry asked him to give them more information he said "What, like 'follow the money'? I never understood that." One episode guide refers to him as "an obvious parody of Deep Throat in The X-Files".
- The Mysterious Informant shows up, and is subverted, in the Frasier episode "Three Days of the Condo." A secretive figure approaches Frasier in the car garage of his apartment building and urges him to stand as a candidate against the current chair of the condo board in the upcoming election. When Frasier asks why his informant insists on remaining anonymous, the figure replies that he's redecorating his bathroom and doesn't want his bidet request to be denied. Then he gets in his car and zooms away.
Frasier: That would work better without the vanity plates, Dr. Dorfman.
Daphne: Wouldn't this be more anonymous if it didn't say, 'From the desk of Doctor William M. Dorfman'?
- Later in the episode, Frasier's Mysterious Informant sends him an "anonymous" letter saying the building tenants are supporting Frasier.
- This trope was parodied in Happy Days when Milwaukee is in the midst of a bitter garbage strike and Richie is investigating a story about it. Fonzie says he has a source, but since he wants to be anonymous, he will only appear as a silhouette on a window blind standing outside to give yes or no signs to questions. When he steps forward, Richie notes that it is obviously Al, but Fonz insists that Richie plays along. Reluctantly, he cooperates with his questions until Al forgets himself and answers a question by talking. Now with the silliness completely pointless, Richie opens the blind and the two finish their conversation normally.
- Rebel in Heroes volume 4. But it was not that hard to guess his true identity.
- Star Trek: Deep Space Nine. In "Improbable Cause" Odo meets with a Cardassian who keeps his face in shadow, claiming that he's altered his appearance since they last worked together (during the Bajoran Occupation). He was meant to be a recurring character but this was dropped, with main character Garak (a Cardassian 'tailor' with a Mysterious Past) filling in for the intelligence gathering role.
- Castle had a secret informant for the conspiracy involving Beckett's mother's murder. Instead of helping solve the case, however, his job was to tell Castle when to tell Beckett to back off an investigation, so the murder wouldn't come after her too. He was apparently killed and had his identity revealed, but showed up for one last meeting in the same mysterious manner even though he was addressed by name.
- The 1990's X-Files spoof The X Fools had the husky-voiced "Sore Throat" (always introduced as "our mysterious informant"). Once when Agent Smolder asked why he always met him in a parking garage, Sore Throat replied that he'd forgotten where he'd parked his station wagon back in '89 and was still looking for it.
- Metal Gear Solid:
- Used in both the first installment and Metal Gear Solid 2. The mysterious informants both dub themselves "Deep Throat", although the second then says to call him Mr. X (The X-Files) because Raiden, in Fangirl mode, made comparisons to the Shadow Moses "Deep Throat".
- Then subverted in the fourth game, where Snake guesses who the mysterious informant is about three sentences into the conversation:
Snake: Is this...Jack?
- The G-Man in the Half-Life series.
- The original Max Payne gave us Alfred Woden, who supplied Max with useful data throughout the game, before revealing himself as the head of the counter-conspiracy to Project Valhalla and giving him the name of the Final Boss in the endgame.
- The Simpsons parodied this in one episode with a trenchcoat-wearing, cigarette-smoking Mr. Smithers.
- Family Guy has also had one, with the shadowed Mysterious Informant obviously being Kermit The Frog. In another episode where they had become a reality TV family and Meg was kicked out of the family for being boring, Peter and Lois met her in this fashion, complete with offering her a cigarette.
- Used in The Fairly OddParents! when Tootie gives Timmy's parents information about her sister Vicky's evil deeds under the alias of "Deep Toot" (the name of which Timmy's dad finds hilarious).
- The Mole in Ozzy & Drix. He's not entirely sane, nor is he that good at disappearing.
- Star Wars Rebels: In the first season, the Lothal Rebels have an informant referred to as "Fulcrum", whose identity is kept secret. Eventually they are revealed as former Jedi Ahsoka Tano, working as part of a larger network of Rebel cells throughout the galaxy. In Season 3, another "Fulcrum" provides the Rebels with intelligence about Imperial operations. This time, it turns out to be Agent Kallus.
- Arthur: In the episode "Buster the Myth-Maker", after Buster hears a supposed rumor of a pair of escaped Siberian tigers living in the nearby nature reserve, he and Arthur meet with a masked informant named Deep Float, who claims to have more information. Of course, Deep Float is Brain, whose Mom accidentally blows his cover and he made the whole thing about the tigers up just to see how people would react.
- Real-life example and Trope Maker: "Deep Throat", the Watergate informant whose identity (William Mark Felt Sr.) was unknown for over 30 years before he finally revealed himself in 2005. So ubiquitous, nearly every Mysterious Informant is either an outright reference/parody or at least has some aspects gleaned from Deep Throat. However, some aspects of the trope draw heavily from the Popcultural Osmosis of All the President's Men; the real-life Deep Throat's identity was a mystery to the general public, but Bob Woodward knew exactly who he was talking to.