"What happened to the mouse?" occurs when a minor character, action, or very minor plotline is suddenly dropped from the story for no apparent reason, without any real explanation about what happened to it, and without a resolution.
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, if it's a character that's disappeared, 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.
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... in the theatrical cut, anyway.
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 as a Brick Joke is Something We Forgot.
Compare with Left Hanging, Uncertain Doom, Kudzu Plot, Red Herring Twist, Out of Focus, Put on a Bus. Related tropes include Never Found the Body and "What Now?" Ending. May involve a Shrug of God. See also Offscreen Inertia if you imagine the plot line still stuck at that spot for eternity.
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- Fairy Tales
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- Live-Action TV
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- Web Original
- Western Animation
- Take a Break, a British magazine which publishes readers' Real Life stories, once featured a story about a young girl, Cassie Griggs, who was disqualified from a talent contest after her mother was accused of trying to pass another girl off as Cassie. At the mother's request, Cassie was allowed to perform, but was not given any marks, resulting in her coming last. However, as no follow-up has (to date) been published, it's impossible to know how this setback affected Cassie's attitude to talent contests in the long term. She could have picked herself up and entered another contest, or her confidence could have been knocked so badly that she was never able to perform again. We just don't know.
- 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. He later goes on to say that he "[doesn't] know what to do". The music video suggests his plan is to commit suicide.
- Hansel and Gretel (the originals). They release the Seven Deadly Sins on the world from their adoptive mother's corpse, and we never know what happened to them after that, or why the heck they did it. Next we see them, they've reincarnated as Conchita's servants.
- 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, possibly because she's unremarkable in a tale of the remarkable - her life's achievements amount to marrying according to her station and bearing a son (her son's accomplishments boil down to being a lesser Knight of the Round Table who goes on one quest, fails miserably, and has to be rescued by Lancelot).
- 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, where God rebukes the rest of Job's "friends".
- A common interpretation is that Elihu doesn't get rebuked by God because his points, against both Job and the other companions, were correct. If anything he's sort of an inversion—Job's three friends are mentioned for thirty-odd chapters before Elihu suddenly speaks up out of nowhere. Then again, Elihu could just simply show up as a troll wanting to get his two cents in before disappearing.
- If Elihu gets it, then Satan must be fuming...one of the two main protagonists who have a bet over the temptation and scarification of Job, he isn't involved any more after the first few chapters.
- 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.
- There's a pastor's story about a nice guy whose family went off to Christmas service without him. He wasn't a believer, because he doesn't get why God would become man. After his family leaves, some birds fly into his window in the heavy snow, and he tries to herd them into his warm barn nearby. After being frustrated in his attempts, he muses that if he were a bird, he'd be able to get them to understand. Then the church bells happen to start ringing, and he sinks to his knees as the Eureka Moment washes over him. The story ends there, with no mention of what happened to the birds.
- In The Eddas, specifically the Prose Edda, the first man and woman are created by Odin and his brothers Vili and Ve. These brothers are never mentioned again anywhere, despite the obvious importance of such characters. Some people have rationalised this by suggesting that they're avatars of Odin himself, who occasionally appears as a trinity to confuse people. In the Poetic Edda, the three who defeated Ymir are referenced as Odin, Hoenir, and Lodur — Hoenir being a once-mentioned god who acts as a hostage after the war with the Vanir (traded for Njorth, Frey, and Freyja). There are some reasons to think that Lodur might be another name for Loki. Still, this is the older and less-mentioned version, meaning that it might just be a mistake, or a fragment of a different myth.
- Thomas Paine wonders in his book The Age of Reason what happened with the dead who rose after Jesus died according to the Gospel of Matthew. Did they go home, back to their graves, or what? It's never said.
- 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.
- An In-Universe example in Peanuts, as Snoopy is writing his novel. He links all of the various subplots together in one sentence and boasts about how nicely everything fits together... that is until Linus reads it and asks, "But what about the king?" Snoopy throws his typewriter at him.
- Often occurs in Professional Wrestling, after Tonight in This Very Ring is invoked (as mentioned on that page).
- An especially egregious one from WWE 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 frame (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. (John Cena did lampshade the plot thread just after John Laurinaitis assumed power as GM, arguing that WWE should "bring back the computer.") Almost a year later, and long after anyone cared, it was eventually revealed that it was Hornswoggle, an apparent reference to when he was equally anti-climactically revealed to be Vince McMahon's supposed long lost son.
- GTV, a hidden camera segment during the Attitude Era. It was never revealed who was behind the camera. According to WWE's web series, "Five Things," the person running GTV was going to be Tom Green as part of a working relationship between WWE and MTV. However this angle never played out, so when GTV was dropped, the man behind the camera remained a mystery for at least a decade.
- Then there was that time Samoa Joe got kidnapped by ninjas. He was gone for like a month or so, came back, and nothing ever came out of it — considering how Joe was acting very similar to how Abyss was acting at the time, it was widely believed he was originally slated to be a member of Immortal. Of course, this was neither the first nor last time TNA did something like this, with Vince Russo booking and all.
- During Season 3 of Lucha Underground, Sexy Star was harassed by a mysterious tormentor who put a spider in her locker, then sent her one in a present delivered by a clueless Ricky Mandel. Another spider was also seen crawling ominously across the floor (or wobbling haplessly across the floor as it was dragged by a piece of string) behind Sexy without her noticing in another scene where she talked with her friend The Mack. Initially she believed she was being harassed by old rival Mariposa (of the Moth Tribe) and although Mariposa denied it, Sexy beat her up in a match. Then when spider-themed luchador Veneno debuted (and promptly got squashed by Cage) Sexy ran out hysterically accusing him of being behind the spiders and laying into him, but during a mask vs mask match arranged between them Veneno was (illegally) unmasked by Joey Ryan and revealed to be an alias of Cortez Castro, removing him from suspicion. And after that... it was never mentioned again, with Sexy moving on to a totally unrelated feud with Taya. In the later episodes of Season 4, it was revealed to have been Reklusa, a spider-themed woman associated with Sexy's nemesis Marty the Moth. Marty sent Reklusa to beat up Sexy Star outside her home, off-camera, to explain Sexy's departure from LU after her real-life fall from grace.
- American Top 40: An occasional feature was "Whatever Happened To ... ?" where host Casey Kasem would profile a one-hit wonder, or early prolific star of the rock era who suddenly disappeared off the charts, quit recording, etc. Casey would simply explain what said artist (or group, as appropriately) had been doing in recent years, if they were involved with current projects, and so forth. Sometimes, he'd even play the song they were best known for.
- One of the most popular "Whatever Happened To ... ?" stories was of Jeanine Deckers, a Belgian known as The Singing Nun, whose song Dominique hit No. 1 in the US in late 1963. Casey's stories on Deckers would always explain that The Singing Nun gave all royalties to the convent but left it in 1966, and later the Belgian government made a claim for back taxes to the tune of $63,000 ... more than Deckers could afford, and no documentation existed that she had donated anything to charity. (The common stories are that her attorney failed to document it and/or that the Catholic church had either destroyed all records of it after they and Deckers broke ties, or that they simply did not have any more responsibility for her and did not have the funds.) Updated several times through the years, the final chapter came in 1985 when Casey announced that Deckers had died (of suicide) at age 51.
- Two entire specials were based on the "What Happened to the Mouse" concept one in July 1973 and the other in April 1975 where Casey played the biggest singles by the One-Hit Wonder acts of the rock era. The 1975 special had a slightly different chart, with a few different songs added and a different No. 1 song.
- Janis Ian, whose 1968 hit "Society's Child" was played for the 1973 show, was deleted from the 1975 updated special. She had just released a new single, "At Seventeen", and although it had yet to make the Hot 100 there were already strong vibes about the song. The good feeling was justified: The song became a long-running hit in the summer of 75, eventually peaking at No. 7.
- 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.
- Billy Connolly performed a long, long routine beginning with his account of a mysterious body found in the street in one of the more exclusive and upmarket suburbs of Edinburgh. He then meanders off into the intricacies of going to the toilet on aircraft, and how the food chain works, and the sheer logistics of so many people on board aircraft who will all need to use the toilet at some point... he gets back to the mystery corpse in Corstorphine (and its effect on local house prices) about twenty-five minutes later. By which time everyone's forgotten how the story started.
- Sideswipe in Transformers: The Ride is last seen getting sucked into Devastator's vortex. It is never made clear whether he was destroyed or made it out in time.
- 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.
- Real life famous missing persons cases could be considered this. The most (in)famous is probably Amelia Earhart, who disappeared while flying over the Pacific. The most likely explanation is she just crashed in the ocean somewhere, but that hasn't stopped people (in real life and in fiction) from speculating that she was abducted by aliens, went into another dimension, or other such theories.
So, er, guys, what did actually happen to the mouse?