What Happened to the Mouse?

A phrase used to decry the abrupt removal of a minor element, be it a character, action, or plotline. The person or thing in question is suddenly dropped from the story for no apparent reason with no resolution, nor any explanation as to what happened to it.

There are several main reasons this happens: in movies, the most common is that scenes are excised in editing, but references to them still remain elsewhere in the film. Another common reason is that a Wrong Genre Savvy audience mistakenly attached too much importance to what always was intended to be a throwaway. A third is that The Law of Conservation of Detail was not properly applied: a Bit Character was a little too lively, so that he didn't appear a throw-away, as why was that much detail given for one?

If the element comes back just as you've forgotten about it, this is actually a Brick Joke or a Chekhov's Gun. If the element doesn't come back, but the show hangs a lampshade on it at the end, then it's Something We Forgot. If it escapes your notice until after the show is over and you've gotten up to go to the fridge to make a sandwich, it's Fridge Logic.

Alternately, it's a variation on the What Now? Ending; not only are we unclear what happens to the character, but this also can leave doubts as to whether they even survived once they broke away from the other characters.

Another character or the Narrator may remark that they were never heard from again.

The trope's name refers to a scene in The Last Emperor in which the title character violently throws his beloved pet mouse offscreen. There's no sound of the mouse hitting anything, but it's never seen again, leaving its fate ambiguous.

What Happened to the Mouse moments can be very rich soil for Epileptic Trees or Wild Mass Guessing.

Not to be confused with Aborted Arc, which is when a major story arc or plotline is dropped without resolution, or Chuck Cunningham Syndrome, where a major character just plain disappears.

A What Happened To The Mouse that is deliberately created and where the creators have no intention of ever resolving the question is a Noodle Incident. A What Happened To The Mouse that is returned to after an extended period of time and answered is a Brick Joke.

Often the result of a Wacky Wayside Tribe, a Forgotten Fallen Friend, or a Big Lipped Alligator Moment.

Compare with Left Hanging, Kudzu Plot, Red Herring Twist, Out of Focus. Related tropes include Never Found the Body and What Now? Ending. May involve a Shrug of God.

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 * Tony Jr., who was on the first Frosted Flakes boxes with his father Tony (who replaced Katy the Kangaroo). He disappeared in 1956, only to come back as a Brick Joke in 1977 as the mascot of Frosted Rice.
 * When Frosted Rice moved over to be a product of the Rice Krispies line, Tony Jr. again disappeared.
 * Bob and Quienno, the other two chefs of Cinnamon Toast Crunch; the most common and accepted of Epileptic Trees is that Wendell killed them.
 * There was a British TV campaign in which an alien from the planet Zarg claimed his world was dying and could only be saved by a soft drink called Quosh. Nothing was ever heard from Zarg again, and one can only fear the worst.

Animated Films

 * What Happened to the Mouse?/Animated Films

Anime And Manga

 * What Happened to the Mouse?/Anime And Manga

Comics

 * What Happened to the Mouse?/Comics

Films -- Live Action

 * The Trope Namer was one very brief scene in 1987's The Last Emperor, when a character flings his pet mouse out of shot while standing in a hallway. The mouse is never mentioned again, leading some audience members to invoke the trope by name.
 * The Extended Cut released on DVD answers the question. The answer: About what you'd expect when a mouse is thrown against a wall, although the mouse used for the shot was not real and no mice were injured in making the film.
 * In Mel Gibson's Apocalypto, the children were simply left behind by Middle Eye and the rest of the hunters. None of them are seen again in the end, leaving many Unfortunate Implications and Fridge Horror behind.
 * The Jurassic Park films: In the first film we never know what happened to the stolen embryos: They are last seen being rapidly buried in the mud; the subplot involving InGen's rival company BioSyn and its attempt to seize the dinosaur embryos as well as its sleazy representative, Lewis Dogson, also disappear in the sequels (although they were the major antagonists in the sequel novel, they were left out of the movie adaptation). The upcoming series of games by Telltale Games are touted to answer some of those questions.
 * We also never learn the fate of the sick triceratops from the first film. The book explained that it had gotten sick from eating poisonous plants when picking up gizzard stones. This was dropped from the film (possibly due to time constraints). Instead we hear that it was NOT the poisonous plants which leaves the poor triceratops fate unknown.
 * I always thought that the triceratops was gaining the ability to reproduce.
 * Lampshaded by Spielberg himself on the special features for the most recent DVD/Blu-ray release. Before reading The Lost World, he had assumed that Crichton's sequel would involve the stolen embryos.
 * Dodson states that there's only enough coolant in the can for a few hours. It can be assumed that the embryos died after the coolant ran out.
 * The Wild Women of Wongo. For the first half of the movie it's established that a tribe of "Ape Men" are about to attack. A grand total of two show up, get killed, and the whole invasion is never mentioned again. So two men are a tribe, then?
 * The Kids Are All Right. The main character's bad friend drags him down the wrong path for the first half of the film, but around the halfway mark, after a scene where the friend literally kicks a dog, both the friend and the dog disappear from the story. Neither are ever mentioned nor seen again.
 * In Iron Man 2, the kid who tries to fire his toy at the big robot? He stays there. And at the end, when the robots explode? Yeah. Kid go boom.
 * His scene was before the police arrived to evacuate people, wasn't it?
 * Never-mind the robots' self-destruct. There were DOZENS of the things, all of them programmed to find and destroy Iron Man. Tony only took care of that one. Did any other drone find the kid after Tony flew elsewhere?
 * On a smaller note, what happened to the bird? We don't see it again after, and we must assume he made provisions for it.
 * What happened to Ivan's first bird? Ivan cares about it too much to just leave it in his room when he goes to Monaco knowing he'll likely get killed or put in jail after attacking Tony, and he's clearly upset that Hammer tried to use another bird when he couldn't find the first one.
 * The Room. Most of the plotlines are left unresolved. Some are discarded the moment they are introduced. What happened with the drugs, or the breast cancer, or the new client at Johnny's bank, or Mark thinking about moving to a new place, or Peter the psychiatrist.
 * Spice World lampshades and subverts this when Melanie C asks the viewers: 'what happened with the bomb on the bus?'
 * In the TV movie adaptation of The Christmas Shoes, the main character's mother dies. As The Nostalgia Chick points out, no one ever brings it up again for the rest of the movie.
 * Manos: The Hands of Fate: Torgo got away. Word of God says that he was going to return in Manos 2, which was "sadly" never made.
 * In The Wizard of Oz
 * The Wicked Witch of the West mentions as she sends out the flying monkeys that she is "sending a little bug to take the fight out of them." This was a reference to the Cut Song "The Jitterbug", which would have followed that scene.
 * Miss Gulch is presumably still going to come back for Toto. Her dream counterpart was defeated, but she wasn't.
 * Happens twice in Troll 2. The first time, it's not too bad -- Drew is knocked unconscious and wakes to the sound of a blender. If you can hear over the bad sound-mixing, Creedence has announced that she's going to feed him a milkshake full of that slime that turns you into a plant, and implicitly, full of Arnold as well. So we can assume that Drew gets eaten. However, Brent's disappearance from the film is nothing short of baffling: after the infamous popcorn sex-scene, we get a brief shot of him covered in popcorn muttering "no more, no more popcorn", and then he's gone from the rest of the movie. He's not even in the car when the Waits family and Elliot drive back from Nilbog.
 * In It Came from Outer Space 2 a blob engulfs various terrestrial life forms, starting with a coyote, and sends alien copies of each one out into the world. At the end,, leaving all the humans it engulfed behind... but what happened to the coyote?
 * Cult film The Doom Generation has a disproportionate number of these. Multiple characters vow revenge on the protagonists after mistaking one of them for a former lover, but only two of them ever show up again. The FBI is shown holding a briefing about the protagonists' involvement in a murder-suicide, but they never show up again. It's a weird movie.
 * In Mystery Men, Dr. Annabel Leek, the Big Bad's lover and henchwoman, simply vanishes without a trace halfway through the film and is never mentioned again.
 * Apocalypse Now: What happened to the dog? This is still the most asked question by all the actors from the film. There is also the matter of the surfboard. Apocalypse Now Redux includes a lot of deleted scenes which answer most of the questions (but still leaves a few hanging).
 * The Movie of Mystery Science Theater 3000 had an infamous one where Crow picks up a chainsaw in Tom's room and even says "Hey, a chainsaw!" Nothing else happens with this afterward, thanks to Executive Meddling forcing a completely different ending than the original one where Crow uses the chainsaw in yet another escape attempt. It still more or less works as a random throwaway joke.
 * In Taken, while looking for his kidnapped daughter, Bryan's investigation leads him to a woman that has been forced into drug addiction. He is in the process of cleaning out her system when she gives him a new lead. He promptly rushes off, leaving her barely coherent, with a saline drip in her arm, in a random hotel room. She is never mentioned again. He presumably left her in the care of the hotel owner, whom he knew.
 * In Cannibal! The Musical, Alferd Packer spends much of his time in prison building a dollhouse, which never amounts to anything. Trey Parker says this wasn't really supposed to be a plot point, and was just a reference to the real Alfred Packer's hobby of building dollhouses, but he admits there should have at least been a scene where he finishes the dollhouse.
 * Escape from New York: "You wanna know what they did to Fresno Bob?" You'll never know. It's actually revealed in the Novelization.
 * About 20 minutes before My Fair Lady ends Col. Pickering decides to search for poor little Eliza who went AWOL. He determinedly walks out of the library set and we never see him or hear of him again.
 * Quentin Tarantino's Death Proof: What happened to their actress friend Lee, whom they left alone with a creepy hillbilly Jasper? It seems unlikely that Jasper would try anything too criminal, given that he knows several people will be arriving to collect her in a few minutes. However, Word of God says that Jasper, who also appears in Kill Bill, does in fact rape her.
 * In the Three Stooges short "Cookoo Cavaliers", the Stooges run a beauty salon. When asked to bleach some women's hair, they inadvertently take out some bottles of hair remover. At one point, the hair remover gets sprayed all over a dog, and Curly is shown beginning to wipe off the dog with a towel. But the dog is never seen again, despite this being a very obvious setup for a joke where the dog's fur falls off.
 * What happens to the third Treadstone agent, Manheim, in The Bourne Identity? He shows up throughout the movie, does his job and vanishes. Then in the next movie, Bourne meets a guy named Jarda who says they are the last two agents. Did Manheim get replaced?
 * In Arachnophobia, Ross' friend Chris survives the spider infestation and manages to escape from the house with the family; he is last seen trying to pull Ross out of the house on a ladder but is knocked over. He is never seen again after that.
 * In the original version of The Blob, considerable emphasis is placed on the old man's puppy for much of the film. It precipitates several important scenes, and is shown to be okay after each Blob encounter. Until the supermarket scene (which it clearly survived). After that, it is never seen or mentioned. Even Jane's little brother, who was promised the puppy and was very excited about it, never brings it up.
 * The old man's dog in the remake isn't accounted for either, but it's only in two scenes, so it isn't nearly as odd.
 * When Steve and Jane go to the movie theater to enlist the help of Steve's friends to warn the town of the blob, the girlfriends of Steve's friends also go along to help. Once they get the attention of many of the townsfolk, Steve's friends stick around, but their girlfriends disappear for the rest of the movie.
 * In House of Flying Daggers, the eponymous society has been discovered and the police have been sent in. There's a shot of a few troops advancing cautiously through the bamboo forest. Then, the fate of the House and the police are dropped in favour of the main characters dying very slowly.
 * There's a particularly monstrous moment of this in the dire Duel knock-off Wheels of Terror: the heroine is driving a bus full of schoolchildren when she decides to chase the car that's just abducted her daughter. She lets the schoolchildren out at an abandoned gas station in the middle of nowhere, and they are never mentioned again. There's an explosion, which may have been meant to indicate that they died, but it's not very clear.
 * In The Rats, the heroine's friend Jay is the first person to be bitten by the rats. She survives the attack but is then hospitalized with septicemia and halfway through the movie a scene establishes her as being in a very critical condition. We never find out whether she lives or dies and she is never seen or mentioned again after that scene.
 * In Poltergeist 3, teenage couple Donna and Scott are pulled through a Portal Pool and onto the Other Side. Then, at the end of the film, Donna is returned safe and sound to her family. As for Scott? The film crew reluctantly admitted that, when they did a last-minute reshoot of the ending, they simply forgot about him. The question of what happened to Scott took on new life as the internet brought fans together to offer their own theories: presumably, he's still Trapped in Another World.
 * In Metropolis, Freder agrees to stand in for an exhausted worker, telling him to go to his servant Josophat's house for the time being. The worker instead steals Freder's money and goes on a spree through the city's pleasure district. A subplot involving him originally followed, but due to missing footage (some of which was only recently discovered), nearly all cuts of the film currently available omit any further mention of him.
 * Pan's Labyrinth: When Ofelia escapes from the Pale Man, she breaks her chalk and leaves a piece behind, and this action is filmed in such a way as to make sure the viewer knows that there is a piece of chalk there that the Pale Man could use to escape. Straight into her bedroom, no less. And while that would have undermined the ambiguity of the film, that same ambiguity made it worryingly possible.
 * Several early scenes in Crocodile Dundee imply that Mick is a croc poacher, but this is never mentioned again once they get to New York. It might simply be intended to convey that Mick is an irreverant rural type who plays by his own rules rather than follow the laws of civilized society, which is basically how he stays.
 * Noxeema did deliver Clara's letter to Mr Robert Mitchum once they got to Hollywood in To Wong Fu Thanks for Everything Julie Newmar didn't she? Well, didn't she?
 * Sophie in Halloweentown High. When she and the other two Piper kids left for school, she completely vanished from the movie. You think she would've cared about the main plot where if Marnie fails to make the Halloweentown High student transfer a success, then her family's powers could be taken away. It's pretty blatant that the creators didn't care for Sophie anymore now that she aged. This is evident in Return To Halloweentown where she and Grandma Aggie got Put on a Bus. Even then, Grandma Aggie at least had two appearances; Sophie was only briefly mentioned.
 * Luke never gets any appearances or references past the second film too. As does Kal, who is said to not have been destroyed yet never shows up again.
 * In Hallmark's 1999 adaptation of Alice in Wonderland, Alice saves three playing cards who were about to be beheaded by the Queen of Hearts for planting white roses instead of red ones, by telling them to jump into her pocket. That's the last we ever hear from them.
 * The disappearance of Birdy midway through All About Eve.
 * The Coca-Cola Kid actually introduces us to a real mouse early on in the story, and shows the main character interacting with it briefly a couple of times, although it seems to be destined to be forgotten since it has no significance in the plot. But, in a wonderful case of last-minute trope aversion, the mouse plays a notable role in the final scene.
 * In Halls of Anger, some white teenagers are bused to a predominately black school. The blonde girl gets cornered in the locker room by some black girls who proceed to rip her clothes off. We cut to a race riot outside, the standard Teacher Who Wants to Make a Difference (is this a trope?) makes a rousing speech to calm everyone down, The End. What happened to the blonde?
 * In Big House, USA a man named Baker is arrested for kidnapping a boy named Danny and holding him for ransom. Danny was not in the fire tower where Baker left him. Even the narrator at the end of the movie admits no one knows what happened to Danny.
 * There are 10 "Basterds" in Inglourious Basterds, not counting Hicox, but counting Aldo Raine, Hugo Stiglitz, and the "eight. Jewish. American. soldiers." Two are onscreen, alive, in the final shot, two die in the theater, two more die in the tavern. That leaves four Basterds whose fates are unaccounted for.
 * Word of God (through a script) says that any Bastards who didn't appear in or after the tavern scene were dead by that point.
 * In The Mummy Returns, Imhotep resurrects four palace guards. All four charge out of the museum and crush Rick's car. However, only three of them are accounted for in the ensuing fight scene.
 * According to the original script, the fourth was supposed to attack Alex after the bus had come to a stop. However, director Stephen Sommers decided to cut the scene short in order to get on with the story.
 * Mr. Bigglesworth, Dr. Evil's bald cat in the Austin Powers films, is last briefly seen near the beginning of the second film, then disappears throughout the rest of the movie with no explanation. He's only seen in a flashback (with full hair) in the third movie.
 * While the third movie does have some explaining to do, Mr Bigglesworth's disappearance in the second is explained: Dr Evil just didn't taking him back in time.
 * In the 2009 movie Obsessed, Lisa the stalker apparently gets flowers complete with handwritten card from the man she's after, Derek (who wants absolutely nothing to do with the woman), while she's in the hospital. The movie never explains how she got them or who wrote the card, and they are never mentioned again in the film.
 * In The Day After Tomorrow Jake Gyllenhaal's rival for Emmy Rossum's affections talks about trying to get to his younger brother early in the film. The last mention of this is just before Gyllenhaal's character almost drowns while calling his dad. It's implied that the brother dies in the tragedy.
 * Shaun of the Dead has several that are addressed in DVD extras, such as how Shaun lured the zombies away from the pub and survived, how Shaun got zombie Ed back to his house and what happened to Diane who just disappeared into a crowd of zombies at one point near the end and never seen again (she managed to climb into a tree where she passed out, woke up when all the zombies were gone and order was restored, but decided to stay up in the tree anyways just to be safe where she survived by eating her boyfriend's leg).
 * Ginger Snaps has one of these. While the core of the plot revolves around the two sisters, their mother, and the older sister's boyfriend, the girls' father is an important secondary character. He is last seen briefly just before the climax of the film begins, and is never seen or heard from again.
 * The Grim Reaper is apparently still running amok in the "real" world at the end of Last Action Hero.
 * Since he declares that he's following a list, and doesn't touch people who aren't on it, he presumably doesn't make any real impact on the world - he only touches people who would have died anyway.
 * In Friday the 13 th Part 2 there is a major character who is last seen at a bar and apparently gets forgotten about entirely by the film. Fans all wanted to know what happened to him. The actor who played him said in an interview that he had always thought the man probably hooked up with a waitress and had a one-night stand.
 * In The Final Chapter (Part 4), Gordon, the dog, is last seen jumping through a window to escape Jason. We never see him again following this. Likewise, Trish does not appear in the fifth or sixth films, even though she survives at the end.
 * In the first act of A Bronx Tale, the main character Calogero is 9, living with his mother and father. There's a Time Skip for the second half of the movie, which takes place about 7 or 8 years later, and his mother is never seen or mentioned. This is a shame because logically she might have been very useful in patching up the strained relationship between Calogero and his father Lorenzo.
 * In the movie of The Addams Family, Tully and Margaret Alford's son, who appears in one scene (and in the credits as "Tully Jr.") but despite the fact that his mother and that his father, he's never spoken of again, not even in Addams Family Values.
 * The most likely resolution is that he was taken in by relatives of his father.
 * John Carpenter's The Thing
 * The fate of . During the final confrontation, he walks off down a corridor in the Arctic base and vanishes promptly from the film. The original script had him getting attacked by a jack-in-the-box like alien, only they cut the scene as the special effects didn't look real enough, and Carpenter liked leaving it ambiguous anyway.
 * It's almost certain that he just got killed off-screen, but it's never actually resolved.
 * Also, we never find out
 * In The Stupids, the main antagonist, the colonel, is last seen when Harvey Atkin's character hits him with a door, knocking him out. We never know what becomes of him later.
 * In the Steve Martin movie, L.A. Story, several characters are very impressed with the reputation of agent Harry Zell. Many different conversations mention him, and Steve Martin himself complains about his current agent, saying he wouldn't get such bad gigs if he worked with Harry Zell. After such a build-up, Harry Zell never appears.
 * Deleted scenes show that Harry Zell is played by an over-the-top John Lithgow, who flies around with a rocket pack, and encourages Steve Martin to skip from place-to-place. (It's the new walking.)
 * An over-the-top John Lithgow? Surely not!
 * In Splash, Freddie is last seen distracting the cops after helping his brother rescue his mermaid girlfriend. The head scientist orders him arrested, and that's the last we see of him. Kind of a dark character ending for such a frothy movie.
 * In the movie Daddy's Girl, near the middle Jody murders her mom's friend Rachel and her death goes unmentioned for the rest of the movie.
 * Puppet Master I had an oriental puppet in the beginning that was placed in the box by Andre Toulon along with the other puppets, hidden away safely. He was never seen again.
 * The Harry Potter films are a bit tricky regarding this trope, since the movies could accurately be considered one hugely long film that's simply been chopped into manageable-length chunks. In many cases, what appears to be a What Happened to the Mouse? is resolved in a later movie. But sometimes, the Compressed Adaptation doesn't allow for it. Best example is Goblet of Fire, where we get the long interview scene with the infuriating Rita Skeeter but she disappears, never to be mentioned again and never gets the well-deserved comeuppance that scene makes us so look forward to.
 * Don't forget Percy Weasley, Ron's older brother. He was in the first film, but disappears until the 5th where he has a non-speaking role. In the books, he and his father are having a fight for the duration, which explains his absence, but in the movies, nothing is mentioned about it. He's just gone (and his father never even mentions him again).
 * Well, he finished school. So as long as he doesn't become teacher it is only natural to not see him through most of the movies. And as for the times when they are not in school, he could be working.
 * If you look carefully, you can see Percy in the background a few times in the final film standing with the rest of Hogwart's defenders, and sitting with the rest of the Weasley family after the battle.
 * People who have not read the books may wonder as to why Barty Crouch Jr. from Goblet of Fire does not make a reappearance in later films after Azkaban sees a mass breakout, and other significant Death Eaters like Wormtail and Bellatrix are clearly identified. He'd be easy to notice, given his loyalty and insanity matched only by Bellatrix. Obviously, of course, it would create a plot hole for Fudge's denial of Voldemort's return in Order of the Phoenix if Barty did not receive the Dementor's Kiss as he did in the book.
 * One of the worst examples of this trope comes in the last two movies. Just like in the books, the first Deathly Hallows movie plants unsettling clues about Dumbledore's backstory and family. The second movie never explains this in the slightest, despite a full history being given in the books.
 * Crabbe. He disappears from the last film entirely. The filmmakers did this because his actor was arrested on drug charges, but no mention is given to him at all in the film, leaving question as to why Goyle is seen without him for the first time in the series.
 * In The Karate Kid remake (2010), when Dre and his mother move into their apartment in China, Dre meets a blond boy who befriends him. Not long thereafter, he is never seen again.
 * You can actually see him cheering on Dre alongside Dre's mom and the Love Interest at the final tournament. However, he still makes no appearances between his initial introduction and appearing at the tournament, making many wonder where he was, as well as causing some mild surprised at seeing him appear again.
 * In Piranha 3D Derrick's assistant Andrew vanishes just before Derrick's boat hits a rock and begins to sink. Presumably he is eaten by the piranha but his disappearance is weird since every other named character with lines who dies does so graphically on screen.
 * According to Word of God he was also supposed to get a graphic death (specifically his nose being bitten off) but the scene was cut due to budget limitations. The scene is in the Blu-Ray bonus features (unfortunately only half finished).
 * In Kick-Ass, we never find out what happens to Angie D'Amico at the end. Or to Mr. Bitey.
 * 'FUCK YOU, MR. BITEY!'
 * Remember Anamaria, the female pirate from the first Pirates of the Caribbean? She just vanished and doesn't appear in the later movies even thought the rest of Sparrow's crew is seen again.
 * It's possible that the PoTC franchise was originally going to have two female characters - the dainty noble and the female pirate. Due to The Smurfette Principle, they were eventually combined into a dainty noble who wants to be a female pirate, but accidentally left in Anamaria even though a lot of her scenes probably were rewritten to have Elizabeth in them instead.
 * Again,
 * Whatever happened to Pugsley the Iguana in The Terminator? Did Sarah ever miss him?
 * Considering that she got herself a German Shepherd to warn her if any more Terminators came after her, I don't think the iguana would have been much use. There's also the possibility that it was killed when the Terminator wrecked the place anyway.
 * In Death Wish 3, Kersey's friend leaves in the middle of a town-wide gunfight to reload his zip gun. He doesn't appear again. He's probably deader than a doornail.
 * Quite a few important plot threads were left unresolved in Super Mario Bros which would have been Left Hanging had they not been put on the sidelines by numerous script rewrites and reshoots. Namely, the parallel world is still slowly dying from lack of clean, renewable resources, Toad and innumerable prisoners are still de-evolved, and rival plumbers Mike and Doug never get their comeuppance. The King remaining a citywide fungus would have been this had Lance Henriksen not cameoed in a reshoot where his character returns to human form after Koopa's defeat.
 * In Paranormal Activity 2, the family pooch is dragged off screen and knocked unconscious; she survives, and the family takes her to the vet to recover. We never see her again or hear about her death, even in the scene set three weeks after she's left there.
 * In Robin Hood (2010 film), in the theatrical cut at least, Prince John's first wife disappears after the scene which establishes she has been displaced by the French princess, which France can use as a pretext to go to war. John says he will ask the Pope for an annulment, but that's all the film gives on this matter.
 * After, Robin and his group head back to England. The rest of the English army (hundreds or thousands of troops) are left behind in France to continue the war. They are never mentioned again. It's like the screen play completely forgot about them, and we are expected to as well.
 * In Mortal Kombat Annihilation Nightwolf tells Liu Kang he must pass three tests before he can defeat Shao Kahn. The first test is courage, which apparently involves having a hatchet thrown at your head to induce a "dream-state." We never learn what the other two tests were.
 * Presumably the second had to do with Jade, given the convenient timing of her entrance. As for the third...?
 * In Ridley Scott's Legend we never hear from Blix and the other goblin again after the first half of the film, despite them being major villains. Also, and this might come under another trope (please edit to include if so), but what exactly was Blunder's "long story" explaining how he came to be one of the bad guys and entrusted by Darkness enough to be one of the trio sent after the unicorn? "Doesn't matter" my arse!
 * Vertigo's Midge vanishes about half-way through the film.
 * In the National Geographic's The Last Lions Ma-di-Tau leaves her prideland choosing to spare her cubs from the males of the marauding pride. When negotiating with the pride later, the infanticidal males are not mentioned, nor how her cubs are spared from them.
 * In Driver, Driver's tattoo is touted as some sort of "Warning: Do Not Screw With" sign. The first time we see it, the sight of it is enough to chase off a 300lb Samoan bouncer. After the film's thirty-minute mark, we neither hear about the tattoo nor see anyone else react to it. We don't even learn what language it's in (though presumably some sort of Samoan dialect), let alone what it actually says.
 * In House II: The Second Story near the middle we are introduced to Bill Towner an eccentric electrician, after discovering the crystal skull uncovers a portal to another dimension he accompanies Jessie and Charlie on their journey and takes his sword with implying he has done things like this in the past, near the end of their travels they arrive in an Aztec temple and save a woman from a sacrifice and Bill stays behind to fight off the remaining Aztecs, he tells them that he will come with them later because he has to attend his son's baseball game, he is never seen again after that.
 * In The Adventures of Ford Fairlane, there are four bad guys. The Big Bad, the guy that just won't die  , and one of the two punk gunslingers gets shot in the mouth. The other punk gunslinger is last seen fighting Jazz and Sam the Sleazebag, and no mention is given to him afterwards.
 * He is clearly at a disadvantage, though, having been hit with a car and possibly having his fingers broken when Sam stepped on them. The fact that Sam and Jazz are next shown entering the building shows that they must have won the fight, and the fact that he doesn't return for revenge at the end  suggests he may be dead.
 * An earlier draft of the script depicts him gaining the upper hand against Sam and subsequently being shot to death by Jazz.
 * In the classic giant ant movie, Them the opening scenes show the Ellinson girl walking in the desert, catatonic after seeing her family devoured. Later, the elder Dr. Medford waves a jar of formic acid under her nose to test his suspicions. She immediately breaks her catatonia, hysterically shrieking, "Them! Them!" The trooper, FBI agent, and two ant experts hastily deposit her in the physician's arms and flee. For all we know, she's still in a strait jacket in the Santa Fe loony bin.
 * Never mind her, she's with her aunt and will be fine. What about the pilot who reported the flying ants and was put in an asylum. The doctors wanted to release him but the FBI agent told them to keep him there and "We'll call you when he's sane." Twenty years later "Hey, what ever happened to .. uh oh"
 * An early scene in What Lies Beneath shows Norman and Claire seeing off their daughter Caitlin at her college dormitory. Then Caitlin is never seen or heard from again, even though we can imagine she would be profoundly affected by  Was Claire just planning to fill her in over Christmas break?
 * If Jamie follows the Mystery Team around, how'd she survive the climax unscathed?
 * The rabbit in Siege of the Dead, apparently they left it in the apartment but do these zombies eat animals and did they leave him out beforehand?
 * In X-Men: First Class, the Hellfire Club is never mentioned or seen again after the early sequence where CIA operative Moira McTaggart (who is investigating it with a colleague) sneaks in and witnesses Emma Frost and Azazel reveal their powers in front of an American general. A retroactive version occurs when you consider that several of the newly-introduced heroes and villains (including ) never appear again in any of the subsequent films in the franchise, and no mention is made of their fate in any later installments.
 * Jackie Chan movies are pretty bad about this.
 * Mr. Hero begins with a plucky reporter mixing Jackie up into a mob plot. She sticks around long after she stops being relevant, only to be grabbed by a mook during the climax. She is not seen again. Maybe she died, but one would think a mob boss being investigated by a reporter would know better. Then again, the mob is never very smart in chan movies.
 * In The Medallion, Jackie and his two partners are enjoying some downtime at one of his partners' house. A cooking montage ensues, featuring the character who owns the house and his wife prominently. Shortly, a small strike force attacks the house. The wife tells Jackie and his partners to run while she holds them off, and reveals herself to be Crazy Prepared. The husband is as surprised as anyone at this, but we never see the wife again.
 * In Casino Royale 1967, the end title theme tells us that there are 'seven James Bonds.' Actually, there are eight in the film - David Niven (Bond himself), Peter Sellers (Tremble, codenamed James Bond), Terence Cooper (Cooper, codenamed James Bond), Woody Allen (Jimmy Bond), Daliah Lavi (Lady James Bond), Joanna Pettet (Mata Bond, codenamed James Bond), Barbara Bouchet (Moneypenny, codenamed James Bond), and Ursula Andress (Vesper, codenamed James Bond). However, the scene that accompanies this song, with the 'seven James Bonds' in Heaven, is lacking Terence Cooper, who apparently somehow DIDN'T die in the casino explosion...?
 * More logical would have been the exclusion of Lady James Bond, aka The Detainer; she was last seen before her attempted escape from a second-story bathroom window. Given the extended period of time between her entering the bathroom and the explosion, we're left to assume that she either fell to her death (the first floor IS rather tall), or that she was still trying to descend the drain-pipe during the explosion.
 * One particularly bad example was the movie Fantastic Voyage. It features Dr. Michaels, the villian, being left behind while the other characters go back to their normal size, despite the fact that Dr. Michaels for some reason doesn't. Isaac Asimov wrote a novellization of the film that corrects this.
 * Mexican Masked Luchador films are not known for rigorous plot construction, but El Santo Y Blue Demon Contra Dracula Y El Hombre Lobo has a particularly bad example of this trope. At the end of the film, the luchador heroes and Santo's girlfriend discuss what to tell the little girl character about her horrifying ordeal when she wakes up in the morning. They decide to tell her it was just a bad dream. Which, yeah, that'll work... at least until she wonders where her mother is, and they have to tell her that she had been transformed into one of the living dead, and (the film implies but does not directly state) sent to her eternal rest after the destruction of the two titular monsters.
 * In Sleeping Dogs, as Smith is brought into the police station, he recognizes the man who earlier paid thugs to commit a False-Flag Operation which gave the government an excuse to institute a police state. He calls this man "Jesperson." At first it seems the other man does not know him, but then he comes into his cell and offers him a deal if gives a scripted confession broadcast live on TV. Smith takes it, which allows him to escape while en route and sets the rest of the plot in motion. However, where or how they knew each other before is never revealed.
 * Judge Dredd. Where did the Rico clones go after they were hatched during the final battle?
 * Since Central said they were only 60% complete and they were caught in the midst of devastating explosions, it's most likely that they died.
 * Close to the climax of Jeepers Creepers 2, we last see Rhonda being tossed out of a car. Her final fate is left unresolved: she is never seen (or even implied to have been) killed, but is not with the survivors at the end.
 * A group of unnamed students are last seen as The Creeper bears down on them. What happened next is up to the imagination.
 * What ever happened to the cute old couple from REC? They're last seen standing in the downstairs lobby area. When all hell breaks loose, we don't even see them in crazy zombie form.
 * Whatever happened to that nuclear scientist in Thunderball after Bond pushed him off the yacht?
 * In Our Gang Follies of 1936, we never find out what happened to the Flory Dory Girl Sixtet, the missing act of the show that Spanky and the gang had to fill in for.
 * Miracle Mile, a Romantic Comedy set during a nuclear war, is told entirely from the perspective of the protagonist, Harry, which means we never find out anything that happens outside his presence. Early on Harry is with a group of people trying to escape the city before it goes kablooie, but once he's separated from them we never find out what happened to them. The most extreme example involves a car thief who helps Harry early in the film then goes off to rescue his sister. The thief reappears later in the movie.
 * At the beginning of Young Adult, Mavis and a man end up in her apartment after a first date. The next morning, she abruptly decides to leave town for a few days -- before he even wakes up. The film ends before she returns. Was her TV still there? We never find out. It provides a Book Ends for a scene later in the movie, but then she's in the guy's house.
 * The Mask. Peggy Brandt, who seems to disappear from the main action towards the end.
 * The Shawshank Redemption: Elmo Blatch, the man who really killed Andy Dufresne's wife and her lover, is never spoken of again after Tommy's story. According to the story, Blatch was doing time for a lesser crime (robbery), so he's probably out again, and considering his amusement at how Andy took the fall, what's stopping him from doing the same sort of thing to others?
 * This is changed from the way events happen in the book. In the book, instead of what happens to him in the film, Tommy is offered a place in a medium-security prison, in exchange for never mentioning Blatch again. When Andy confronts the warden about it, the warden says no one knows where Blatch is. When Andy tries to press the matter, the warden threatens him, which leads to their confrontation (much is made of this battle of wills in the last quarter of the film).
 * Hugo never got his notebook back and it's never mentioned after a while. Did George burn it after all or what?
 * Fans of Tyrone Power's last film, an unjustly obscure John Ford triptych called Rising Of The Moon, sometimes ask what happened to the jackass in the final scene -- the animal, that is. It wanders out of shot during the police sergeant's final soliloquy. Given that everything else in that part of the movie is not what it appears to be, the donkey probably belongs to someone else and is simply headed home.
 * In Guy Ritchie's Sherlock Holmes the very end
 * In the film of The Thirteenth Warrior, the King's son is set up to be a secondary antagonist. One of the thirteen warriors even kills one of his henchmen in a duel as a psychological ploy. However after angrily leaving the scene of the duel he's not seen or referenced again.
 * In Men in Black II, the two Dragons Scrad and Charlie disappear halfway through the film, and are never seen again.
 * In Men in Black II, the two Dragons Scrad and Charlie disappear halfway through the film, and are never seen again.

Literature

 * In the Vitae Sanctorum Britanniae, or "Lives of the Saints of Britain", which predates the 9th century, warfare breaks out when a lovely maiden is kidnapped by King Maelgwn's soldiers. St. Cadog approaches the king and convinces him to repent and recall his army - but never asks for the maiden back, despite her father being an official in Cadog's church. She is never mentioned again.
 * In Robert Bloch's The Yougoslaves (sic), a gang of murderous, Brainwashed and Crazy boys is shown raping a little girl. The boys are eventually killed. No mention is made of what happens to the girl.
 * In Stephen King's The Green Mile, there's a literal "What Happened to the Mouse?" when Mr. Jingles runs away after Eduard Delacroix is executed. Stephen King wrote in the afterward that even he forgot about Mr. Jingles until his wife asked him the question, so he wrote in a resolution.
 * Also from Stephen King, The Langoliers ends with the survivors abruptly and happily arriving back at the airport. Um, that's great, but just how the hell are they going to explain how
 * They mention that they are going to tell the authorities what happened, they just decide to put it off until after the story ends.
 * Again from Stephen King, in his short story "The Jaunt", the protagonist's daughter almost literally asks this question when the protagonist tells the family the story of the eponymous teleportation device's invention. To wit, the inventor ran down to the pet store and tested some white mice out on the machine. Slightly subverted when he euphemistically explains that they "didn't feel so good the first time" after being sent through awake.
 * At the end of Frankenstein, said doctor's brother Ernest is the only member of the family completely unaccounted for by Shelley (the others are all dead).
 * Especially Egregious because the doctor whines and mopes at length about how everyone he loves is dead.
 * 19th century fiction is full to the gills with "What Happened to the Mouse?" scenes, partly because many books of the time were originally written for serialization in magazines. When the writer's on Chapter 24 he might forget or misremember what he wrote in Chapter 1, published two years previously. Dickens was infamous for this.
 * In Anthony Trollope's Barchester Towers, it's stated repeatedly in the first nine chapters that the new bishop will spend most of the year with his wife in London, leaving the actual running of the diocese to his assistant Mr. Slope. But the bishop and his wife never actually leave. (The reason is that Trollope put the book aside for a year, and when he returned changed his mind about what would happen without bothering to rewrite the first nine chapters.)
 * In the original British printing of Good Omens, it is never revealed what happened to Warlock the false antichrist after he is taken to the fields of Meggido by the forces of hell and revealed as a sham. For the American edition the authors added about 700 extra words revealing that he is alive and well, understandably perplexed by his experiences, and heading back to America thanks to some reality-manipulation by Adam.
 * In the Sword of Truth series, Richard's two hulking bodyguards Ulic and Egan disappear from the narrative entirely after Temple of the Winds, and no reference is made to where they are, or what they're doing. Their sudden and conspicuous return to the plot in Confessor seems to suggest Goodkind actually forgot about them entirely.
 * There's also Jebra, the seer who first appears in Stone Of Tears. In the final trilogy, she's brought to the heroes by Shota to tell them about her experiences being caught in city conquered by the Imperial Order . Shota leaves her there, but in the next book she's mentioned as having wandered off, and there's almost no effort made to find her, and she's never referenced again.
 * This happens with a lot of minor characters/villains/etc. throughout the series. Goodkind tends to bring in stuff strictly to serve as a plot device or MacGuffin, and then forget about it after it's served its purpose, or dismiss it with only a cursory mention.
 * Several Warcraft Expanded Universe novels mention princess Calia Menethil, the older sister of Big Bad prince (and now Lich King) Arthas Menethil. Calia's fate has never been revealed; in each book, she simply drops out of sight and is never mentioned again. She is the subject of several Epileptic Trees in fan circles.
 * Averted in Perfume: The Story of a Murderer, which always pauses the narrative to explain what happens to characters that drop out of the plot. Because the main character is a Doom Magnet, everyone he associates with dies soon after they part company.
 * Happens quite a bit A Series of Unfortunate Events. The Quagmires, Friday, and the rest of the island inhabitants in The End, Mr. Poe, and many, many more. Curse you, Lemony Snicket, you psycho author you. Knowing the author, this was probably completely intentional.
 * In the first Sherlock Holmes story "A Study in Scarlet", Watson mentions that he "keeps a bull pup" before moving in with Holmes. Once he moves in, the bull pup is never mentioned again. Maybe it died between two adventures? Though there is an explanation that's seen print is that "to keep a bull pup" is slang for "to have a short temper."
 * In Peter F. Hamilton's Night's Dawn Trilogy, a fairly major character in Book 1, Kelven Solanki, vanishes without a trace at the end of the book after being promoted and assigned as a liaison and advisor to Admiral Meredith Saldana on his flagship. Despite Saldana and his taskforce playing major roles in Books 2 and 3, Solanki is nowhere to be seen. The author later admitted in a Q&A on his website that he had simply completely forgotten about him, but his overall importance to the story had been fulfilled. Given that the ending was so comprehensive that even the fate of a minor car thief who appeared for one paragraph is wrapped up, Solanki's abrupt disappearance seems a bit unfair to the character.
 * Steven Erikson's Malazan Book of the Fallen series is also noteworthy: a full list of characters who appeared briefly and then vanished would be quite long, but chief among them is Tattersail and her reincarnated form, Silverfox, who vanished along with several thousand kickass undead warriors in Book 3. Apparently their story will eventually be told by Erikson's co-writer, Ian Esslemont, several years down the road. Maybe.
 * One of the many things wrong with The Legend of Rah and the Muggles by Nancy Stouffer is the sheer number of mouse plots in the story. The mother of the twin protagonists, having been recently widowed at the start of the story, enters a very heavy flirtation with the palace butler before shipping her kids off to save them from impending doom; what becomes of the mom and the butler, we never know. Later, the twins are deeply involved in the search for a specific treasure chest; when it's found, the bad twin insists on claiming it, to which the good twin consents. Not only is it never mentioned again, but the reader never even finds out what was in the chest that was so important.
 * Romance of the Three Kingdoms raises numerous mouse questions, as might be expected of a semi-historical narrative with Loads and Loads of Characters. To quote the book's 17th-century editor, "A beloved commander, a beloved son, lost for the sake of a woman... but what happened to lady Zou?""
 * In Raymond Chandler's first Philip Marlowe novel The Big Sleep, all of the various murders and crimes are explained, except that of the Sternwoods' chauffeur, Owen Taylor. During filming of the 1946 film adaptation, director Howard Hawks and screenwriters William Faulkner, Leigh Brackett and Jules Furthman sent a cable to Chandler, who later told a friend in a letter: "They sent me a wire... asking me, and dammit I didn't know either."
 * Reiko from James Michener's Hawaii simply disappears toward the end. She's a secondary character with an interesting plotline, but after she's never heard from again, leaving the reader to wonder whether she ever accomplished her thwarted dreams.
 * Tom Robbins' Still Life With Woodpecker hangs a lampshade on this, when Leigh-Cheri's reaction to the story of the Princess and the Toad is "Whatever happened to the Golden Ball?" (that the princess was chasing when she first found the Toad.)
 * In Musashi, a novel based on the life of Miyamoto Musashi, the title character learns that his sister has been arrested as a ploy to lure him out of hiding. He's about to play right into the officers' hands when he's stopped by the kindly priest Takuan, who then imprisons Musashi himself for three years so he can study the classics and become a more thoughtful person. The story promptly forgets all about his sister, except for a brief mention at the end that she's moved to another region and is happily married, with no mention of how she got out of jail.
 * Dan Simmons' Ilium/Olympos cycle. What happened to that mice colony? What happened to that humongous tentacled brain? Where did Caliban go? Did moravecs manage to get rid of those 768 black holes? Can the remaining firmaries be turned on or not? Why didn't anyone care for more than seven years? Who the hell was Quiet and did (s)he actually do anything? Has the quantum stability problem been solved? If yes, then how? Aaargh, so many questions...
 * David Weber's Honorverse is usually rife with Continuity Nods that are explained in excruciating detail just in case you're new to the series... but for some reason, the hoopla raised in Honor Among Enemies, in regards to, is never referenced again. Though Weber did indicate several times that
 * The sheer amount of detail in the Harry Potter books leads to a number of these, too. Harry pulls a cracker and out come, among other things, several live mice. But mice are not throw-aways like the other things in the cracker. Neither Harry nor anyone else is ever mentioned as keeping pet mice. Harry muses that Mrs. Norris got to them.
 * Ludo Bagman is forced to flee from goblins at the end of Goblet of Fire. He is never seen or heard of again.
 * Cornelius Fudge, the Minister of Magic for most of the series. His last official position we hear of is at the start of book 6, where he's been sacked as Minister, but is kept on as liaison between the Ministry and the Muggle Prime Minister. No word at all of him or how he reacted to Voldemort taking over the Ministry in Book 7.
 * It was never explained what was behind the veil though as it is in the Department of Mysteries, it is likely that no-one knows.
 * Even though in the movie, in the book it's obvious that . So, it's fairly clear what lies behind the arch, especially when you take into account what Harry heard from it.
 * In Thomas Harris' Black Sunday, Lander gave his pregnant ex-wife two tickets to the Super Bowl. No mention is made on if she went or what happened to her.
 * In Ender's Shadow, Bean is shown drawing up Ender's army. He decides to add a girl named Wu to his group. He mentions that she was a brilliant tactician, a great shooter, and did well in her studies, but as soon as her commander assigned her to be a toon leader, she filed for transfer and refused to play. No one knew why. In the rest of the book (and in Ender's Game, which takes place at the same time), not only do they never mention her again, they even make it clear that there are no girls in Ender's Army.
 * Early in Tom Clancy's Red Storm Rising, Iceland is conquered by the Soviet Union to allow their submarines and bombers a clean shot at convoys ferrying war material and American reinforcements to Europe, where the ground war is raging. In the course of this operation, the ship carrying the Soviet invasion force is Harpooned and strafed by American fighters, seriously wounding the captain. Much buildup is done about whether or not the captain will survive. As soon as the ship is run ashore (most of the line handlers had been killed, so it couldn't dock) the General of the invading army takes him below to the surgeon, thinking "Maybe there's still enough time." The captain is never mentioned again, leaving the reader to wonder as to his fate.
 * In Reaper Man, Windle is introduced to members of the Fresh Start Club, including someone called "Brother Gorper". All the other members are specifically identified as various types of undead, and most have dialogue or subsequent references, but Gorper (whatever he is) never gets mentioned again.
 * Inverted in the same novel, where Windle recalls receiving a note from Mr. Ixolite the banshee. No such scene is included in the book; presumably, it was supposed to be one of the "three inexplicable phenomena" which Windle ponders on another occasion, because there are only two shown. Instead, it's a Where'd That Mouse Come From? inversion.
 * Pamela Dean's The Secret Country has a "What happened to the relatives" in it: The older cousins, with whom the game was usually played, had emigrated to Australia: the younger cousins were left in Illinois with other relatives while their parents were spending the summer in Australia without them, and thereby hangs the tale. At the end,
 * There's a tragic example in Robin McKinley's Deerskin. After being raped by her father Princess Lissla flees, badly wounded and pregnant with his incestuous child. She is later healed by a goddess, apparently losing several years of memory in the process. No further mention is made of her pregnancy until near the end of the book, when she confronts her father again, and reveals that she miscarried after five months and suppressed the memory.
 * It is mentioned. During the period where she's living in the hut and dazed, she experiences a particularly bad night which results in a huge bloodstain on the floor.
 * In Robert E. Howard's Conan the Barbarian story "Black Colossus", the princess is in command because her brother the king is being held captive and might be either ransomed or handed over to their enemies. While discussing what to do, the first point brought up is whether to enlarge the offer of ransom; only then do they discuss the attacking army, and that, partly because the captor won't take them seriously while they might be overrun. But they deal with the army, and the captive king is never even addressed again.
 * Many, many things are wrong with the Maradonia Saga books, but this one is particularly obvious. Several apparently important characters--including Maya and Joey's parents and brother, the grasshopper Hoppy, and their dog--show up at the beginning and then are forgotten about for the rest of the novel. Some "forgotten" characters do make brief cameos in the ending, but it's never stated what they were doing in the meantime. Was Hoppy just hanging out in Joey's pocket the whole time or what?
 * In the Tortall Universe, it was because of this trope that author Tamora Pierce eventually wrote a short story about what happened to the tree that became man as a result of the mage Numair turning his Evil Counterpart into a tree in the second book of the Immortals quartet.
 * Early on in the Vorkosigan Saga novel The Vor Game, Miles is assigned to Kyril Island as the new Weather Officer. The officer he is replacing has been there so long that he has developed a "nose" for predicting the weather, especially the deadly wah-wahs, which is far more accurate than the available equipment. Miles is briefly terrified that everyone else will notice a sudden drop in the accuracy of reporting when he takes over, but soon has a major confrontation with the commanding officer and is transferred off the island. Presumably the poor patsy who replaces him will be no better at predicting the weather than Miles, but the island is mentioned just once more in a later novel, a decade later in book time, and it's implied that nothing has changed there.
 * Test readers of the book were so distracted by the potential plot relevence of some money being hidden as a relatively minor plot point that the finished novel uses illicit cookies for the same plot purpose to avert this trope.
 * In Lucifers Hammer, Doctor Charlie Sharps leads a group of highly intelligent (not to mention prepared and supplied) scientists out from the Jet Propulsion Laboratory, headed toward the San Joaquin Valley and shelter. Not only are they never seen or heard from again, they are only mentioned once in passing by another character, and then forgotten.
 * In the first Maximum Ride book, the main characters (who are winged humans, part bird, part human, created by some Mad Scientists) have gone years without seeing another genetic experiment like them. When they get to a secret facility in New York, they find several expiriments caged up. Naturally, they set them free. You'd think they'd want to talk to them or interact with them, maybe help them find a safe place, but it never goes anywhere. Over 5 books later, said experiments don't even get a passing mention, they're never thought of again, so it's a plot thread that went nowhere and contributed nothing to the story.
 * Maximum Ride suffers from this a lot. The second book also has the group finding two kids in the woods. While Angel reads their minds enough to know that they aren't experiments, she can tell that they aren't normal kids. The kids use a tracking device to lead people from Itex to the group, and the most that's found out is that they were kidnapped solely for that purpose, and that they would be left to be eaten by something if they failed. The group leaves them in the woods to be recaptured by the company, and they're never thought of again. The third book has an entire facility full of successful experiments, including clones of Max (introduced in the book prior and herself having fallen into this trope until that point), Nudge, and Angel. It's never revealed what happened to the experiments after the facility is captured, and again the group never thinks anything of it. Meanwhile, Fang starts a worldwide revolution via the children that read his blog. You'd think that something like that would get a mention in the next book, but it might as well have not happened for all the aftermath there was.
 * Peter Pan: In Wendy's personal imaginary world, she owns a wolf pup abandoned by its parents. Naturally, when she gets to Neverland the wolf appears and becomes her constant companion--or so the narration claims, since it never gets mentioned again. Surprisingly, this detail was never referenced or expanded on in any adaptations, even though the Disney version could easily have turned the wolf into a cuddly Woodland Creature and the 2003 live-action version could have thrown it into some fight scenes. (There was at least one set of illustrations (Trina Schart Hyman's) which didn't neglect the wolf and showed it hanging around at Wendy's feet in the "Home Under the Ground" scene.)
 * In book four of the Inheritance Cycle Eragon and Arya wind up captured by a group of evil priests. A young novitiate appears and agrees to help them escape. He fails and winds up unconcious, while the more competent Angela comes to the rescue. Eragon insists that they take their would-be rescuer's comatose body with them as they escape the cathedral, however after this the boy is promptly dropped off in an alley and never mentioned again.
 * Why is a raven like a writing desk? was left unsolved by Lewis Carroll...
 * An odd subversion. While never the answer is never given in either of the books - as Dodgson meant for the riddle to be a riddle without an answer - but enough of his fans pestered him about the riddle that he made up an answer:
 * In Lauren Myracle's Rhymes with Witches, the main character's best friend's older sister is described in detail in the first few chapter. However, she is rarely mentioned after that.
 * Towards the middle of Reset -- Never Again, the two villains, who are Asian, try to hire a detective to find the whereabouts of the heroes. It turns out, however, that the detective is a member of the Oriental Exclusion League, and says that she is going to tell their leader, one Tveitmoe, about what had happened. Neither Tveitmoe nor the detective are ever mentioned again, and the villains do not appear to be hampered by any bigots after that.
 * Just before the timeskip in the Thoroughbred series by Joanna Campbell, Ashley reveals she's pregnant with her second child and "due in January" (incidentally, the scene plays out almost exactly the same as did the one in which she revealed her first pregnancy). The next book (and the timeskip) comes around, the series now follows Ashley's now teenaged daughter, and...the daughter is an only child. No mention is made of Ashley's second pregnancy.
 * In some of Tolkien's older works such as The Silmarillion, there are several minor characters that are simply never mentioned again with no resolution, although this can be forgiven since he never completed those works in his lifetime.
 * W.E.B Griffin's The Corps series has many viewpoint characters simply vanish from the narrative, especially when the series timeskips into Korea. While a couple are at least given some resolution, many simply vanish between books.
 * In the sixth book of the 39 Clues series, mentions that  This does not go unnoticed by Amy and Dan, but it is soon forgotten and never brought up again.
 * In The Short Second life of Bree Tanner, Freaky Fred runs away before the newborn army is sent to fight the Cullens. He is never mentioned again in the series, even though the novella ends with Bree mentally begging Edward to be kind to Fred if they ever meet.

Live Action TV

 * What Happened to the Mouse?/Live Action TV

Music

 * Möte i Monsunen, a song from 1935 by the Swedish musician Evert Taube (known to write all manner of gibberish and getting away with it because of his status as a national hero) has an ending very reminiscent of this trope. A sailor by the name of Fritiof encounters another sailor, and tells him of when he sailed across the seas with wild animals on board. A few of the ending lines would be something like this, translated from Swedish: "But, Fritiof, the elephant, what became of it?" "When we meet again, I will give an answer to your question" and then promptly the conversation gives place to a description of how Fritiof rows back to his boat.
 * The Big Pun song Twinz has an opening verse about a gangland hit gone wrong that is so catchy that it pretty much makes the song. Once the listener is told that they killed the wrong man, the hit is never mentioned again. Even worse, the video for the song covers an alternate plot that does not exist in the song.
 * Justin Bieber, in his song Omaha Mall, goes to check out some girls. He says they look good, but you never know in Omaha Mall and suddenly girls are never mentioned again in the song.
 * The Lamb of the Genesis Concept Album The Lamb Lies Down on Broadway is mentioned only once, in the very first song on the album.
 * In James Blunt's "You're Beautiful", the first verse ends with the line "...but I've got a plan." We never find out what this plan involves, or if anything happens as a result of it.

Myths & Religion

 * Older Than Feudalism: Homer did this in The Iliad. He went to the trouble of describing the battle between Aeneas (mortal son of Aphrodite) and Achilles. The Gods saw that Aeneas was about to be killed, and, since he was such a good servant, decided that he didn't deserve to be killed, and took him away from the battle, declaring that he would be the future king of all Trojans yet to come. Homer never mentions him again, and even the other authors of the lost epics only said that he either fled Troy after a bad omen or was captured and spared by the Achaeans. Later Greek authors said that he went to Italy. It took eight hundred years for Virgil to turn this into a Brick Joke. An Epic Brick Joke, at that!
 * Open up a mythology book. Chances are, if you're reading the Perseus story, you'll know that Acrisius, King of Argos, simply had bad luck when it came to having children (or at least males), and learned through the Oracle of Delphi that while he wouldn't have any luck any time soon, his daughter, Danae, would have a child that would eventually kill him. After that, everyone knows that Acrisius stuck Danae in a box and put her in the ocean, where Zeus impregnates Danae in the form of a Golden Shower, thus leading to the creation of an important hero. You never hear about Acrisius again until a long time after, especially in your text. Depending on your version, he's more or less become something of a poor man, and happens to be visiting funeral games where Perseus also happens to be playing. As Acrisius sits in the stands, a stray discus launched by Perseus strikes an unsuspecting Acrisius in the head (this troper's mythology guide had Acrisius struck In the foot.),thus fulfilling the prophecy that his son would kill him. The presence of Acrisius itself seems to combine this trope, Brick Joke, and some sort of Chekhov's Prophecy.
 * In many versions of Arthurian legend, Arthur's mother has three daughters with her first husband: Morgause, Morgan le Fay, and Elaine. The first two play pivotal roles in Arthur's life, but Elaine is typically mentioned once in passing and then never heard from again.
 * The wives of both Cain's and Adam's bloodlines for the first several generations come from seemingly nowhere.
 * Elihu spends a few chapters ranting at the eponymous character of the Book of Job, then disappears and isn't mentioned in the last portion.
 * In the New Testament, we never hear any word of Jesus' stepfather Joseph after the "Did you not know I would be in my Father's house" incident when He was twelve. Church tradition says he passed away some time before Jesus started his ministry.

Newspaper Comics

 * A two-week 1995 FoxTrot storyline had Paige getting the role of Cleopatra in the school's Anthony and Cleopatra play, (with Morton playing Anthony, of course). The story ended before the play started, with Roger noticing Paige's name in the play program. After that strip, the story suddenly ended, with no actual strips of the play being performed, and the story was never mentioned again.
 * In a 2010 Funky Winkerbean storyline, the title character was involved in a near-head-on collision with a woman yaking on a cell phone. This catapulted Funky into a brief Time Travel (or was it) arc. When we come back to the present, Funky's in the hospital with assorted injuries. Not a word was spoken, before or since, about Cell Phone Lady.
 * This 1988 Garfield strip has a blind date of Jon's named Gwen, who dresses as absurdly as he does on dates and finds him cute. Garfield even says "God made two of them!" Although she would have been a good recurring character, perhaps as a Distaff Counterpart of Jon, she was never mentioned again.

Pro Wrestling

 * Often occurs in Professional Wrestling, after Tonight in This Very Ring is invoked (as mentioned on that page).
 * An especially egregious one is from the most recent NXT. At some point it stopped being a competition (which may very well qualify as an example itself) and was more or less third brand not unlike a lesser version of WWE's version of ECW. William Regal was eventually made matchmaker (GM for all intents and purposes) which led to a number of plotlines that were hastily resolved when it was decided NXT would tape exclusively at Full Sail University in Orlando, Florida... all except one: In the last month of the show someone was going around attacking various wrestlers. Percy Watson, Alex Riley and Derrick Bateman all ended up on the receiving end of beat downs by the unknown assailant who attempted to fram (perhaps?) Percy for the latter two attacks. However after the Full Sail tapings WWE decided not to show them until they could secure a TV deal for the revamped NXT and so it's gone back to being taped before Smackdown with all the plotlines dropped... including the mysterious backstage assailant.
 * Another example is the Anonymous Raw GM. After a month or so period where the Raw GM position consisted of Vickie Guerrero and then Bret Hart the GM position was instead given to an anonymous person who issued directives via emails sent to a laptop read by Michael Cole. This continued for a year before Triple H became WWE COO and the Anonymous Raw GM was almost immediately dropped with no resolution or even a hint as to who the GM was actually supposed to be.

Stand-up

 * Eddie Izzard's Dress to Kill tour featured the 'Firework joke' which he repeatedly references throughout his performance then ends the show without telling it. It's lampshaded by several people in the audience who immediately begin asking for it. He doesn't.

Theater

 * Romeo and Juliet: Where the hell does Benvolio go after Mercutio dies?!
 * It has been speculated by a commentary on the book that Benvolio's line "That is the truth or let Benvolio die" is significant, given that he lied and said Tybalt started the fight with Mercutio (when it was the other way around). It is unlikely, however, that he was actually killed, so his disappearance remains a mystery.
 * At least one revision done long after Shakespeare died had one of the nobles at the end of the play announce that Benvolio was also dead. They still fail to mention how.
 * Another common interpretation is related to Benvolio's Meaningful Name. "Benvolio" means goodwill in Latin. He's around for all of the more comedy-like parts -- perhaps Benvolio is only a metaphor after all.
 * In the epilogue to Angels in America, we see Prior, Belize, Louis, and Joe's mother are all pretty chummy with each other five years after the events of the play, but Joe seems to be pretty much forgotten. Maybe he went to Washington?
 * Macbeth. The witches disappear about halfway through the story and never get their comeuppance. Then there's the matter of what happened to Fleance, although audiences at the time would have understood he was to eventually become king.
 * Witches, in Shakespeare's time, were agents of Hell. There was no need for any kind of comeuppance...they served their purpose. Fleance may or may not have become king (given Malcom's age and the importance placed on primogeniture, it was unlikely), but Shakespeare didn't consider that important; what mattered was that Banquo's bloodline survived and would eventually produce King James I.
 * Exactly. The whole point of their intro scene is to say "This is what is going to happen, it's mysterious, you won't understand it until it's too late, and when you do, it will only increase your suffering to finally know what we meant." The witches are evil, to Shakespeare, and don't need a come-uppance.
 * Cyrano De Bergerac: Did Viscount de Valvert survived his Sword Fight with Cyrano at Act I Scene IV or not? The last we see about him was that his friends carried him after his defeat, and after a little mention by Roxane at Act II Scene IV, we never heard of him again.
 * The Taming of the Shrew starts out as a play-within-a-play; a lord and his servants trick a drunken peasant named Christopher Sly into thinking that he's the lord by dressing him up and waiting on him, telling him that he's been mad for years. They all sit down to watch a play about Katerina and Petruchio...and then they don't show up again. One ending has Sly waking up, convinced that he dreamed the whole thing and eager to try the trick of "taming a shrew" out on his own wife; however, many scholars think that it was added later and that Shakespeare never wrote it.
 * In King Lear, Shakespeare decides to Shoo Out the Clowns and have the Fool drop out of the plot after Act 3, even though he was a constant companion of Lear up to that point. Some stage productions interpret this as the Fool dying -- perhaps influenced by the line "My poor fool is hanged" in the last scene, though most critics interpret that line as referring to Cordelia.
 * Similarly, Adam, beloved Old Retainer and sidekick of Orlando in As You Like It, disappears after they arrive in Arden. Since Adam is elderly and nearly starves to death on the journey, some productions imply that he died; scholars speculate that the actor who played him may have needed to double as someone important during the second half of the show. (Whatever Shakespeare's intention was, Adam doesn't die in the source material.)
 * Watching the original play version of Peter Pan, you might wonder, "What happened to that rich cake Hook was going to kill the Lost Boys with"? There are several answers to this question:
 * The probable technical answer, which is that Barrie went through many drafts of the play and certain details were lost or glossed over. Vital to the scheme's success is the fact that the boys have no mother to tell them not to eat such rich cake, so Barrie may have felt no need to explain its failure once Wendy had arrived.
 * A stage direction after Hook enters, discouraged that the boys have found a mother, suggests that he "has perhaps found the large rich damp cake untouched".
 * The novel expands this as one of the Noodle Incident adventures the children have in Neverland: "[The pirates] placed it in one cunning spot after another; but always Wendy snatched it from the hands of her children, so that in time it lost its succulence, and became as hard as a stone, and was used as a missile, and Hook fell over it in the dark."
 * In the musical, the boys find the cake at the end of the "Wendy House" scene. Wendy tells them not to eat it, and they go inside.

Toys

 * Bionicle, due to its nature, has plenty of examples:
 * The Dark Hunters guidebook mentions that Shadow Stealer is currently coming back from a mission and is ready to face his "master", the Shadowed One. It was deemed an irrelevant Narrative Filigree and never touched upon again.
 * The same happened to Aphibax's secret mission to track the events on the island of Voya Nui.
 * Order of Mata Nui agents report in the book Bionicle World that Karzahni is training his Matoran slaves in order to conquer the outer world he just learned of. The plot had been Retconned out of the story, so he went to fight without them, taking his Manas crabs instead.
 * The book also mentioned that Roodaka had become the ruler of her island and will probably train her people to form an army. What became of it: Nothing, as her island was destroyed by Kaiju, and her status was never touched upon.
 * What more, the book revealed the Mana-Ko, formerly believed to be beastial guardians of the Big Bad, were actually secret double agents for the Order (good guys), and would be called into war. The war did happen, but they were never mentioned again.

Video Games

 * What Happened to the Mouse?/Video Games

Web Comics

 * The eponymous slime of Unicorn Jelly simply disappeared after episode 581.
 * Before To Save Her the author claimed it was an intended symbolic plot point about childhood, magic or something or another.
 * In Questionable Content the character Sara just disappears and is never mentioned again. The Cast page lampshades this by saying she was eaten by an allosaurus. Author Jeph Jacques says he just dropped her for being boring.
 * You'd never know in Ciem that resident Depraved Bisexual Poison Dart Eddie even had a sidekick, as he is so quickly brushed aside and never mentioned again. Even Claire Rauscher has the decency to at least return in a later chapter, if only to.
 * A planned  adaptation may even exclude chapter 10 of the comic entirely, making it so that Poison Dart Eddie himself never existed.
 * Sluggy Freelance had a minor one where a reader actually asked, "What happened to the demonic ferret?" The answer was, "She's still there with the other demons, I just forgot to draw her."
 * Get Medieval's Where Are They Now? Epilogue is infamously missing Oneder, Iroth's bodyguard-turned-Muslim holy warrior. In the annotated reruns, Ironychan stated that she left out Oneder (and Sir Gerard) because she felt there was nothing really left to say about them.
 * Also; Asher's kitten. It disappeared shortly after Asher received it and was unmentioned for months, until it reappeared after the "Trip To The Moon" arc. Ironychan has never said whether or not this was planned all along or whether the constant cries of "WHERE'S THE KITTY" caused her to bring it back.
 * Monette's baby, in Something Positive. The full humor and drama of an unplanned pregnancy are played to maximum effect, but Monette's baby disappears from the plot with barely a ripple (subtle clues in the dialogue reveal it was either stillborn or died very shortly after birth). Millholland lampshaded the baby's absence much later in a filler strip in which the baby turned up in a Lost and Found box.
 * Word of God says it was stillborn.
 * Jessica's pregnancy in Better Days, though it's possible that the sequel, Original Life (which follows the children of Better Days' main characters) will bring this up.
 * In Bob and George, on average once per Mega Man game parody, Mega Man would beat one of the Robot Masters without killing them, and for the most part they never showed up again, though they spawned numerous Epileptic Trees. However, on rare occasion they showed up again, especially Shadow Man, who became a running joke due to his stealthy nature and the Epileptic Trees about his disappearance.
 * Shadow Man in particular said, after his initial appearance, that he'd disappear into the background until he was needed once again, which seemed a natural set up for him to return. It was years before he really did, and at every new plot development he was tagged as possibly being behind it. One fancomic lampshaded this by having him come and say the reason he hadn't shown up again was because, as a Ninja he would return and strike when least expected... but the readers kept expecting him.
 * Emily from Mortifer. Last appeared on this page, and was promptly never seen again. This trope was barely averted however, when a fan drew a (spoileriffic) piece of Fan Art Lampshading it, which the author saw, stating that she had completely forgotten about the character and that she would try to find a way to bring her back into the story.
 * Narrowly averted in YU+ME: dream. The author realised she was going to do this with  and so Dropped a Bridge on Him for completeness.
 * Possibly Haban and Breya Andreyasn in Schlock Mercenary, though they had rare appearances for a while before that (after being important supporting characters for years). Made more glaring and worrisome by their last appearance ending on an ominous note, though the enemy AI claimed they were not killed.
 * Of course, ex-admiral Breya is made of "political antimatter", as a figure of some status and renown (especially given how loudly Xinchub's attempt to frame her up in the aftermath of Gatekeepers war crashed)...
 * Sonichu in spades. The author's wild-running attention span has caused him to start and drop so many plots and characters, it isn't even funny.
 * Rumors of War: Who was that walking around as ? Where did disappear to? What about the rest of the characters on the ship in the first Story Arc? What about all those character Nenshe recruited to the Order of Orion? (Some of these turn into Brick Jokes later in the comic.)

Web Original

 * From "Swimming!", an early episode of Lonelygirl15: "Whatever happened to that girl, Cassie?" Over 430 episodes later, we're still none the wiser.
 * The White Parade has a variation of this. Part III sees Ean sending Allys on an errand to fetch a sandwich from the Subway across the street from the hospital where he's staying... only for it to never be mentioned again once it's retrieved.
 * This strange youtube video takes this trope quite literally. It features an animated mouse who just walks across the screen and then is never seen again.
 * The Literal Music Video for Anything For Love has Meat Loaf continue to complain about his dropped necklace long after it stops being relevant to the video's plot.
 * In Kung Tai Ted's review for Tiger Love, Ted becomes so disturbed at the scene where the titular tiger mauls a boy that he breaks character and asks if the child actor actually got killed.
 * The interstitial webisodes aired prior to The Walking Dead's second-season premiere revolved around a survivor named Hannah and her attempts to protect her family from walkers. At the end of the webisodes, Hannah (running to escape the city with her kids) manages to kill a zombie that bites her, and tells her children to run away as fast as they can before she turns. We see what happens to Hannah afterwards (she's eaten by a horde of walkers, and becomes the titular "bicycle girl" that Rick Grimes discovers in the pilot episode), but what happened to her kids?
 * The Nostalgia Critic invokes this trope with his "but what happened to Boomer?" rants in various movie reviews, everytime a character's fate, especially if it was a dog, is not resolved in a movie, at least for a while. If it is before the end credits roll, a short "Boomer will live!" scene is shown. Boomer was a pet dog in one of the reviewed movies.

Western Animation

 * What Happened to the Mouse?/Western Animation

But we still don't know what happened to the mouse!