->''"ODA NEVER FORGETS."''
-->-- [[MemeticMutation Oft-stated quote]] regarding '''Creator/EiichiroOda'''

An item gets used. You relax a bit, maybe admire the way it fits into the plot if it's done well. But then, when you were least expecting it, it gets used again. Thanks to TheLawOfConservationOfDetail, you had put the item out of your mind because it had served its purpose--but what you didn't realize was that it wasn't a single-shot ChekhovsGun and is actually coming back.

Particularly common in {{Adventure Game}}s, where a particular item, setting, or character might get used three or four times. While this is a good thing in principle, being more realistic, leading to fewer loose ends, and going some way to countering StupidityIsTheOnlyOption, it can throw newbies to the genre who might get stuck on a puzzle for hours because they didn't realize that they'd had an item all the time, they'd just forgotten about it. Of course, this cuts both ways: you might try out something that worked before, [[SoLastSeason but this time it doesn't]].

Compare BrickJoke (the gun is dismissed and forgotten ''before'' it's used even once, and then comes back). The player may have to apply Chekhov's Boomerang in video games for {{Final Exam Boss}}es.
----
!!Examples:

[[foldercontrol]]

[[folder: Anime and Manga ]]
* In ''{{Heroman}}'' Joey activates [[spoiler:Heroman's Augment ability in Episode 4]]. [[spoiler:Fast-forward 19 episodes later, and it is used [[CrowningMomentOfAwesome to spectacular effect]]]].
* ''Manga/FullmetalAlchemist'', simply put, does not have throwaway characters. Characters thought to be one time bits will show up in given time. Corpses long forgotten will re-emerge.
** Remember Kimblee? Guy who blows stuff up, saves Ed once, yada-yada? Well, he's dead and absorbed, so now we don't have to see him ever agai-[[spoiler:oh wait, there he is inside Pride, stopping the little bastard from taking over Ed's body]]. And that is without mentioning his Philosopher's Stone.
** Remember Havoc's girlfriend? He was finally going to have a great relationship, but then Mustang makes him dump her. Well, that was pretty funny. She won't be coming back aga-[[spoiler:Oh hello, Lust...]]
** The idea of the exchange with Truth comes back again and again!
** Well, not completely true: There were a few characters in [[Anime/FullmetalAlchemist the 2003 anime version]] that never appeared again, but they were just in {{Filler}} episodes. And even then, some of them still have a (slight) impact on the plot.
** Even in ''Brotherhood'', based more closely off the manga. You can safely ignore Isaac Mcdougall, the filler character made just for this anime and the subject of the one filler episode, at the end of which he dies, right? There's no way his crazy OC plot will come back in later episodes, right? ''Wrong''.
** In a flashback to Xerxes, we see Father [[spoiler:lied to the king about where the nation-spanning transmutation circle was centered, leaving the king to get turned into a Philosopher stone with the rest of the country]]. Near the end of the manga, he pulls this same trick ''again'', as [[spoiler:the apparent center the heroes were trying to keep Father away from was a decoy; the real one was under his chessboard.]]
* ''Manga/PokemonSpecial'' manga. Bloody hell.
** [[spoiler:Yellow turns up in the second chapter as the protagonist and [[SamusIsAGirl as a girl]], Lance turns out to be the guy instructing Silver, Ruby summons ''Celebi'' in the RS saga, "Guile" turns out to be Archie, and the whole Emerald saga was a ploy to change the previous chapter's protagonists back to normal from being petrified.]]
** On the object end of things, there's [[spoiler:the Grand Meteor, the Rainbow and Silver Wings, the memory firelighter, and Blue's Silph Scope]] with two or more convenient uses after their initial appearance. There are probably more.
* In ''Manga/XxxHolic'' and ''Manga/TsubasaReservoirChronicle'' (a linked story so confusing they use each others [[ChekhovsGun guns]]) notes that a person's true name gives you power over them. Watanuki in the first series gives his name to Yuuko. Later, [[spoiler:it's revealed that this name is a fake, a decoy. He doesn't actually ''know'' his real name.]] But then, [[spoiler:Fay turns out to be the main character Fay's twin brother, who made a wish for him to get free, and 'Fay' has been using his name since.]] Think it's done? Wrong! [[spoiler:Kurogane reveals that only Tomoyo knows his true name.]] Also [[spoiler:Syaoran lied at the beginning of the story about what his name was, and is using the name of his father.]] However, it is likely that uh... Mugetsu's name is real, at least. Apart from that, who knows?
* Sanosuke's Zanbattou in ''RurouniKenshin''. Just when you thought it was gone for good after his fight with Kenshin, [[spoiler:it reappears in his fight with Inui: This time, held together with [[CrowningMomentofAwesome GIGANTIC STAPLES]].]]
** Sanosuke also makes use of this trope a second time in the [[FillerArc anime only]] Shogo Amakusa arc when he unexpectedly gives Shozo the same bombs which he used against Shishio's [[CoolBoat battleship: Purgatory]]. [[spoiler: Only 31 episodes later.]]
* ''MahouSenseiNegima'' has one that crosses continuities; an antagonist attacks Negi using an attack that originated in KenAkamatsu's previous manga ''LoveHina''. There's even WordOfGod to support the idea that they take place in the same universe.
** [[spoiler: Chao Lingshen's]] involvement in the plot counts as this; after her first appearance, she functions as the BigBad about a dozen volumes later. Then another dozen or so volumes after that, she becomes plot-important again.
** Also [[spoiler: Fate Averruncus]]. He shows up in the Kyoto arc (volumes 4-6), working as a henchman. Fifteen or so volumes later, he makes a reappearance. Turns out [[spoiler: he's the BigBad.]]
* ''CodeGeass'' makes [[spoiler:Suzaku]] into a ChekhovsGunman riding a boomerang when Zero Geasses him to "Live!" in order to prevent a HeroicSacrifice ([[SenselessSacrifice for the sake of the villains, stopping his own goals from being achieved]]) that could have killed Lelouch, Kallen, and potentially Euphemia, all of which are Suzaku's own friends, as well as collapse much of the Black Knight organisation. Later, his Knightmare Frame is armed with a [[spoiler:FLEIYA, which he swears up and down he won't actually use. This lasts until Kallen shows up, full of rage and piloting a superior Knightmare. She tears him to shreds and when the Geass activates, the only way he can "live" is to fire the nuke and kill half of Tokyo.]] It activates several other times as well, this is just the most noteworthy one.
** A number of characters prove to be recurring when we thought they'd only be of the one-shot variety. Most of the characters (the named ones, anyhow) in the series have a series of overlapping relationships, and so show up in multiple contexts. Lady Marianne receives several different interpretations, [[WhamEpisode none of which we were expecting]]. As well, Nina Einstein starts as a quiet classmate of Lelouch, who then meets Princess Euphemia and develops a crush, who ''then'' attempts to build a bomb in the school basement when said crush [[spoiler:goes crazy and dies]], who then shows up a year later building the bomb properly, who ''then'' sees it used on Tokyo, and ''then'' she finally shows up working for Lelouch, building a device that stops the AU-nuke from being used again. Villetta, one of the first characters to be geassed by Lelouch, proves to be one of the most troublesome for him at various key moments.
* In ''Manga/{{Naruto}}'', Uchiha Shisui's only role seems to be to explain who Itachi killed to get his Mangekyou Sharingan. ''237 chapters later'', it is revealed that the Sharingan that [[spoiler: Danzo hid under his eye bandage]] belonged to him. He returns again during the Fourth Ninja World War, when his ''other'' Sharingan helps [[spoiler: a resurrected Itachi break from Kabuto's Edo Tensei MindControl]].
** Sasuke's Shadow Shuriken technique, used once in the first arc, is used again ''over 350 chapters later'' when he is fighting Itachi. It returns again another 50 chapters later when Naruto uses it with a ''Rasen''shuriken against Pain.
** Naruto's Rasenshuriken technique, initially a melee attack, was used a few times during the Immortals Arc. Due to the damage it causes to his own body, the Hokage bans him from using it any further. About 100 chapters later, Naruto gets around the problem by using Sage Mode to convert it to a projectile attack. It still has another limitation in that he can only use it a few times, rendering it useless if it misses the target or the opponent dodges it. He gets around that problem too, about another 100 chapters later, and now it is ''remote-controllable'' using his other SuperMode.
** Upon returning from his training with Jiraiya, Naruto gifts Kakashi one of Jiraiya's novels. He uses it to good effect during Kakashi's bell test. It is never mentioned again until the Pain arc, during which it becomes important to decode a message.
** Another one of Jiraiya's novels about a battle against a rogue ninja, serves as an inspiration to [[spoiler: Namikaze Minato]] to choose his son's name. It is brought up again during the Pain arc for a different reason.
** Way back in Chapter 8, Kakashi warns Team 7, after a very poor demonstration of teamwork, that if they do not improve, a time may come when they are forced to sacrifice a team member for their mission. To emphasise the point, he tells Sakura to kill Naruto or else he would kill Sasuke. This situation is played out in Kakashi's backstory, where he had to choose between rescuing his teammate Rin and completing his mission, and eventually leads to [[spoiler: what everyone considered Obito's death]]. The situation appears again in ''Nagato'''s backstory later, where he had to choose between killing either of his two teammates, and ''that'' leads to [[spoiler: Yahiko's death]]. ''Still'' later, it is revealed that Kakashi was a witness to ''another'' such situation, wherein to save Konoha, Kakashi was forced to [[spoiler: kill Rin, who was forcibly made a Jinchuriki for the purpose of attacking Konoha]].
* ''Manga/OnePiece'' does this frequently with some of the LoadsAndLoadsOfCharacters (like [[spoiler:Hatchi]] and [[spoiler:Laboon]]) ending up important hundreds of chapters after they were introduced. In fact "Oda never forgets" has become something of a meme among ''One Piece'' fandom.
* ''Anime/{{Monster}}'' - Johann's candy, the story books, Three Frogs, and many others.
* Pulled off in a massive scale in the last arc of the ''Manga/DesertPunk'' anime, where half the apparently one-shot characters all show back up [[spoiler:as part of LaResistance]].
* In ''Anime/YuGiOhGX'' [[ArtifactofDoom The Phantom Demons/Sacred Beasts cards]] are the main plot point of Season 1. They're defeated and sealed away. They suddenly become relevant again mid-way through Season 3 when the new villain obtains them and uses them in a single duel. They then disappear again. Towards the end of Season 3, they make another appearance. And then they're never mentioned again, despite having the power to [[TheEndOfTheWorldAsWeKnowIt destroy the world]].
* This trope can be applied to numerous cards in the series. Due to the formula, many cards make a single appearance and never show up again. Others are used extremely often. However, if a card is used twice and makes a major comeback in later, more important duels, if they're cards that tip the balance to the hero's favor, and if they're cards the viewer has forgotten about, then the trope applies.
* Shortly after the end of her [[DayInTheLimelight arc]] we find out that Erza, who we saw in an earlier chapter of ''Manga/FairyTail'' loosing an eye when she was young, got a fake magic eye as a replacement. Because of this she only receives half the blast from a petrification gaze and is easily broken out the spell. After about another arc people forget she ever lost an eye at all, until she uses the fake one to see through an illusion.
* The Ultra Sacred water (presumably the water from the Garlic Junior arc of Z, and not similarly named waters from Dragon Ball) in ''{{Dragonball}} GT'', which was useful to get the characters cured from Baby's control.
* Remember that time way back near the beginning of ''MagicalGirlLyricalNanoha'' where the heroine used a little spell called "Area Search?" Well, in ''Anime/StrikerS'', it comes back ''big time.'' [[spoiler: [[{{Determinator}} Nanoha]] uses it to sniff out [[SmugSnake Quattro]], before [[DungeonBypass blasting through the ship's bulkheads]] and taking her out with a [[WaveMotionGun multi-cartridge-enhanced Divine Buster.]]]]
* Lancia's Ring in ''Manga/KatekyoHitmanReborn!''. A small gift from Lancia to Tsuna in the end of the Varia Arc, forgetting about it causes Tsuna, Gokudera, and Lal Mirch to be attacked by a Strau Mosca, then be found by [[spoiler: TYL!Yamamoto]]. Then, at the very end of the Future Arc, [[spoiler: during the first part of Tsuna and Byakuran's [[CurbStompBattle final battle]], it's having the ring in his breast pocket that prevents Tsuna from being killed by Byakuran's Mini White Dragon]].
* The Lagann Impact in ''GurrenLagann'' might count: its primary use is to hijack enemy Ganmen which it does successfully nearly all of the time, the only exception being the Lazengann which blew up it's own arm before it could've been taken over. Afterwards, it's completely forgotten... until the final battle where it {{One Hit Kill}}s the Anti-Spiral.
* In the first episode of [[AnimatedAdaptation animated series]] of [[VideoGame/SuperRobotWarsOriginalGeneration ''Super Robot Wars Original Generation: The Inspector'']], [[spoiler:Axel apparently kills Beowulf (the MirrorUniverse Kyosuke) with his mecha's Rocket Punch. However, Beowulf turns up alive and well and becomes the BigBad of the series, handily trouncing the heroes. When all hope looks lost, Kyosuke sees the Rocket Punch buried in the Gespenst Mk-III's torso and strikes it, pushing it into the Mk-III's cockpit and crushing Beowulf.]]
* ''{{Gundam00}}'': in episode 19, Tieria utilized the almost secret of his Gundam Virtue - Nadleeh and its Trial System - which control any mobile suit connected to the Veda computer. The Trial System demonstrates its ability to stop the Gundam Thrones dead in their tracks but is disabled by someone hacked into Veda. Never to be seen again, especially not after being disabled [[spoiler:and the original Gundams being decimated at the end of the first season]]? [[spoiler:Dead wrong.]] [[spoiler:The Trial System makes a surprising victory appearance through the Seravee/Seraphim just after control of Veda is wrestled back from Ribbons during the second to final episode and stops a neverending swarm of kamikaze Trans-Am Gundam.]]
** After realizing Veda might no longer be safe, Celestial Being programs new operating systems for the Gundams so that they can operate independently of Veda (in season one). They also have to fall back on this strategy quickly after speculating on the risk. During the final episode (of season two), [[spoiler:Ribbons resorts to the Veda-independent Reborns Gundam and uses it to destroy Seraphim, which was using it's Trial System to disable all of the Veda-connected villains.]]
* In ''LightNovel/ZeroNoTsukaima'', Princess Henrietta passed to Louise her mother's ring the "Water Ruby" as a good luck charm after assigning her to a mission in Albion. The ring became vital when it was used to convince Prince Wales of Albion that Louise is really Tristain's ambassador. [[spoiler: It is however more than just a Tristainian royal keepsake as it was later revealed to be essential in unlocking the secrets of Void magic.]]
* The first season of ''StarBlazers / SpaceBattleshipYamato'' was fairly episodic in nature, and usually involved the Gamilons trying a particular plan or gizmo against the heroes which would not turn up again. One episode involved a tract of space laced with floating space mines. Another episode had a teleportation device that could make a Gamilon battleship appear out of nowhere. In the second season, long after we'd forgotten about both, Desslok brilliantly combined the two by teleporting a mess of space mines directly in front of the ship's WaveMotionGun, so they can't fire it without blowing up their own ship. Clever guy, Desslok.
* ''LightNovel/ACertainMagicalIndex'' has pulled this off a few times: the Capacity Down system, with the extremely useful effect of crippling any espers within its range, used in ''Railgun'' is later used against GROUP in volume 15. Body Crystal, a drug that amplifies an esper's powers, is a refinement of the red crystal developed in that same story arc. ''The Queen of the Adriatic Sea'' appears dealt with partway through the series, only to [[spoiler:resurface as a weapon against Fiamma of the Right during World War III.]] The author has also taken to introducing concepts and characters in one-off side stories only to have them appear in later primary story arcs (Leivina Birdway and her "Dawn-Colored Sunlight" magic cabal being a prime example).
* The Spirit Egg in the anime version of ''YuYuHakusho''.
* ''Anime/AngelBeats'' has "My Song", a ballad played by Iwasawa at the beginning of Episode 3. She is told not to play it because it would not be useful as a distraction for the school's students. Later in the episode, she plays it [[spoiler: before accepting her past and disappearing.]]
* In ''LightNovel/HaiyoreNyarkoSan'', Nyarko gives Mahiro a good luck charm[[note]]Which Creator/HPLovecraft fans will recognize as the Shining Trapezohedron[[/note]] in the first light novel (or the second episode of the TV series). It proves its use later that same story, letting him [[CallOnMe summon Nyarko in a time of great need]]. The Trapezohedron boomerangs back a few times, such as summoning Nyarko (who was left home with a cold) in ''Nyarko-San W'' episode 10, but the most prominent example is in the third novel/episode 10, where [[spoiler:it acts as a PocketProtector and keeps [[FreakyFridayFlip Nyarko-in-Mahiro]] from being killed by the BigBad.]]
* Three examples from ''Manga/BlackButler'':
** First thereís an early mention that Aleister Chamber is involved with black magic groups, which overlaps with ChekhovsHobby. Later on he turns out to be part of the Phoenix Society [[spoiler: and tries to use the Bizarre Dolls for his own purposes.]] In the next arc, his connections to the Phoenix Society [[spoiler: allow his nephew, Edgar Redmond, to contact the Undertaker.]]
** During the School Arc, the elephant that Soma rides into school on also becomes important twice- and yet it still manages to be hilarious every time it shows up. First it gets spooked and destroys Maurice Coleís room, forcing him to share with Soma and giving Soma the chance to catch him sending notes to his underlings and [[spoiler: get photos of his real face.]] Then Sebastian uses it to transport water during the fire.
** In the both seasons of the anime, Cielís ring has actual plot importance, although this trope only applies in the second season because in the first season it serves an entirely different purpose. It [[spoiler: houses his soul, prompting his memory loss and the entire second season.]] Then a different ring is later used [[spoiler: to store Aloiseís soul]] the same way Cielís ring was used. The effect lasts much longer (in terms of screen time, at least) and plays an even more crucial role in the plot then the first example does.
[[/folder]]

[[folder: Comic Books ]]
* In PreCrisis ''ComicBook/{{Superman}}'' comics, a minor SilverAge story involved Superman gathering kryptonite from around the world, forming it into a small ''island'' in the ocean (there were a ''lot'' of kryptonite meteorites in those days!), and then propelling the whole thing into outer space to get rid of it. Still, it was the SilverAge, so kryptonite kept turning up on Earth despite this. Years later, DCComics decided to stop using kryptonite as an easy plot device, so they had a freak accident destroy all the kryptonite on Earth, and the Superman comics went for a while with no (or at least fewer) stories involving the stuff. Writers missed it though, so years after ''that,'' they had the long-forgotten "Superman Island" of kryptonite return from space and scatter the stuff all over the world again.
* PostCrisis has the ''ComicBook/{{Superman}}'' storyline EndingBattle, where dozens of super-villains gang up on Supes. During the fight, he disposes of Neutron by tossing him into orbit in outer-space. Two issues later, the villains are down to four but have cornered a worn-out Superman on a deserted island. Superman suddenly tells them that Neutron should fall out of orbit any moment now, which he does, provoking a nuclear blast that disrupts the fight and gives Superman a chance to leave after the BigBad.
* Creator/AlanMoore once wrote a story prophesying the end of the Comicbook/GreenLantern Corps. Fast-forward a decade or two, and it's become the basis for the ''ComicBook/BlackestNight'' event.
** Actually used twice. The "Blackest Night" Prophecy was also used in the early 1990's when the Green Lantern Corps was destroyed for the first time, after when Hal Jordan went mad with grief and became Parallax. "Blackest Night" was also the title of one of the comics leading to the end of that same arc, implying that Parallax/Jordan caused the Blackest Night. The Universe has since been rebooted and the prophecy retconned, however, so it's likely that in canon the first occurrence was just a warm-up.
*** The first one didn't include Sodam Yat or Ranxx the Sentient City, both mentioned in the original Creator/AlanMoore story.
* ''ComicBook/{{X-Men}}'': Gambit falls somewhere between this and ForgottenPhlebotinum. One of his powers is the ability to charm or hypnotize people simply by talking to them. Despite there being a countless number of times this ability would be really helpful, it's typically seen once every few years. However, he ''does'' still use it, so it's not completely forgotten.
* In ''ComicBook/SonicTheHedgehog'', Dr. Eggman uses the blue Chaos Emerald to initiate a CosmicRetcon, turning Mobius into its video game counterpart. Sonic fixes this a few issues later, going Super and shunting things back to normal, but the Chaos Emerald disappeared. Two years later, and it's shunted into the ''ComicBook/MegaMan'' universe, setting the stage for the two franchises' crossover.
* {{Transmetropolitan}}: I-Pollen Damage, Source Gas and Spider's ''second'' back-up gun.
[[/folder]]

[[folder:Fan Fiction]]
* FanFic/AGrowingAffection: Naruto's Five Points Rasengan might qualify; In book 1 its development is discussed, then he uses it in a fight in the first half of the book. Then in the middle of book 2 he shows it in the Jonin Trials, but does not use it in combat. It gets used again near the end of book 3, and again near the end of book 4.
** [[spoiler: a better example might be the Reaper Death Seal dividing the Fox's chakra in Naruto. When the Fox merges with Naruto, the Akatsuki scientists recognize that the seals are gone; they have been talking about the Eight Trigrams Divination Seal and Divine Arts: Zodiac Seal by name, but one could assume the third seal is gone, too. But at the end of book 3, the Reaper Seal suddenly reappears on Naruto as the Reaper uses it as a medium to send the Hokages back to stall Orochimaru. So again, one might think the seal is gone. Instead it shows up again at the end of book 4, when Naruto removes it to get the rest of the Fox's chakra, refilling his own reserves and unlocking his Shin Tensei Kitsune jutsu.]]
* ''FanFic/DirtySympathy'': Apollo's first-aid kit. It is mentioned in the beginning of the story when Apollo has to go the pharmacy to pick up burn cream and bandages because he didn't have them in his kit and uses it to treat Klavier's injuries and is seen again when he uses it to treat Trucy's firework burns. When Phoenix and Edgeworth try to piece together [[spoiler: why Klavier and Apollo suddenly left,]] they find the first aid kit in Apollo's room which Edgeworth uses to confirm Apollo's story that he was physically abused by his former boss.
** Klavier's ring. Klavier accidentally left it behind after sleeping with Apollo, telling Daryan that he lost it after sleeping with a groupie. Apollo tries to return it after he reunites with Klavier, but Klavier lets him keep it because it would be suspicious for him to get it back. [[spoiler: When Phoenix finds it in Apollo's room after Apollo suddenly leaves, he realizes that Apollo and Klavier, whom he thought were simply colleagues, were actually lovers.]]
[[/folder]]

[[folder:Film -Animated]]
* ''WesternAnimation/DespicableMe''. Anti-gravity serum + minion. HilarityEnsues.
* ''WesternAnimation/DespicableMe2'' has the memorable [[spoiler: lipstick taser.]]
* The character of Bonnie from ''WesternAnimation/ToyStory3'' who first plays a part in [[spoiler: rescuing Woody from the daycare centre and helping him find Andy's house]]. She then comes back into play [[spoiler: at the end of the movie where Woody writes down her street address on the box of toys so Andy can leave them with her rather than locking them up in the attic]].
[[/folder]]

[[folder:Film -Live Action]]
* ''Franchise/BackToTheFuture'':
** The hoverboard in the ''Film/BackToTheFuture'' sequels. At the end of ''Part II'', Marty uses a hoverboard he brought back from 2015 to get back [[TimelineALteringMacGuffin Gray's Sports Almanac]]. He uses the hoverboard again at the end of ''Part III''.
** Lightning being enough to qualify for the 1.21 gigawatts. Obviously important in the first film, then it works again ''accidentally'' in the second.
** Bullet-proof vest, too. All three films. Sort of.
* ''Film/GIJoeTheRiseOfCobra'': The tracking device.
* The ivory pipe in ''Film/NationalTreasure''. It's almost a Swiss Army MacGuffin.
* ''Film/HistoryOfTheWorldPartI'': "Only a miracle can save us now!"
* Big Jim Slade in ''Film/TheKentuckyFriedMovie''.
* Doug's statue-impaled mattress in ''Film/TheHangover''.
* All of the Creator/MattHelm films starring Creator/DeanMartin have at least one of these.
* ''Franchise/PiratesOfTheCaribbean'':
** Jack's compass. It is introduced in the first film as a (presumably broken) compass that doesn't point north, however later in the movie Jack uses it to lead the Interceptor to the Isla de Muerta. It then becomes a sort of MacGuffin in ''Dead Man's Chest'' when it is revealed to lead the user to whatever they want most.
** In ''The Curse of the Black Pearl'', Will's sword throwing is first used to stop Jack from escaping, but at the end he saves Jack from the gallows with it. Although this looks like it would be a ChekhovsSkill, Will's skill at throwing swords was part of the screenplay before the scene at the gallows was even created.
* ''Film/{{Oblivion 2013}}'': The fact that [[StuffBlowingUp drone power cores are pretty devastating when they go off]] comes to bite both sides of the conflict [[NukeEm in the ass]] [[OutrunTheFireball a few times]].
* In ''Film/StormOverAsia'', the Mongol herder protagonist has to flee for his life when the EvilColonialist cheats him over the price of a fox pelt, leading to a violent confrontation. Much later in the film, the herder is outraged to see the fox pelt he was cheated over draped around the shoulders of a colonialist officer's wife.
* The rat poison in ''[[Film/TheHousemaid1960 The Housemaid]]''. Dong-sik's son Chang-soon thinks Myung-sook poisoned his water with it, so she drinks the water instead. Then she later tricks Chang-soon into thinking she poisoned him, causing him to run off in a panic, fall down the stairs, and die. Then Mrs. Kim tries to kill her with it, but it turns out that Myung-sook had switched out the rat poison for sugar water. Then Myung-sook and Dong-sik kill themselves by drinking the rat poison.
[[/folder]]

[[folder:Literature]]
* ''Literature/ASeriesOfUnfortunateEvents'': In ''The Ersatz Elevator'' Violet attempts to use fire tongs for several different things, including welding and noisemakers. They only are effective for their final use, however.
* In ''Literature/TheHungerGames'' The nightlock berries that Peeta accidentally kills Foxface with come up again after [[spoiler: it's announced that the new rule that there can be two winners of the Hunger Games if they are in the same district has been revoked, Katniss and Peeta use them to threaten to kill themselves and ensure there is no winner. They come up again in Mockingjay where the rebels inspired by these events create a suicide pill they name Nightlock (whether it's made from Nightlock berries is unknown) also saying Nightlock 3 times will turn the Holo into a bomb.]]
* SandyMitchell's ''TabletopGame/{{Warhammer 40000}}'' novel:
** Ferik Jurgen, assistant to Commissar Literature/CiaphasCain, [[FakeUltimateHero HERO OF THE IMPERIUM!]]. His unique status as a "blank" makes him impossibly useful and extremely effective, and at the most unusually convenient moments...
** There's the good Commissar's skill with a chainsword and las pistol, as well as his "friendly" relationship with a certain Ordo Xenos Inquisitor.
* After having been completely ignored since the second book, the [[spoiler:Boxes of Orden]] become the key to the final resolution of the ''Literature/SwordOfTruth'' series.
* A regular event in the ''Literature/HarryPotter'' books.
** One good example is basilisk venom. This is established in the second book to be a deadly and destructive substance. This property comes into play at the end of the book when Harry [[spoiler:uses a basilisk fang to destroy the magic diary]]. ''Five books later'', Harry, Ron, and Hermione are desperate for a way to [[spoiler:destroy the Horcruxes they've collected - and Ron goes down to the Chamber of Secrets and grabs an armful of basilisk fangs]].
** On that note, [[spoiler:Godric Gryffindor's sword is a twofold ChekhovsBoomerang between its multiple reappearances and the fact that it's goblin-made and therefore "imbibes only that which strengthens [it]," when Harry used it to slay the basilisk, the sword absorbed the venom. Thus, Ron is later able to use the sword to destroy the locket Horcrux.]]
** In [[Literature/HarryPotterAndTheDeathlyHallows Deathly Hallows]], remember the passage early in the book where [[PlotPoint Scrimgeour denies Harry its ownership, claiming the sword presents itself to any worthy Gryffindor?]] Admit it, you probably forgot about it by the time Griphook got hold of the sword, taking it away from the plot. [[spoiler:And then, as the story is reaching its climax and the sword itself is long forgotten, Neville draws it from the flaming Sorting Hat and beheads Nagini with it, destroying Voldemort's last Horcrux and earning his personal CrowningMomentOfAwesome by the way]]. Now that's a Chekhov's Boomerang!
** For that matter, Tom Riddle's diary is one as well -- when it appeared in the second book it seemed like a mere MacGuffin for Harry to face Voldemort again. After it was destroyed, it seemed to have served its purpose and could be forgotten about like the Philosopher's Stone. And then in sixth book, Dumbledore explains about the Horcruxes and it's revealed that the diary was a major clue.
** Dumbledore's Chocolate Frog card is probably the oldest boomerang in Jo's arsenal; Harry reads it on his first train ride to Hogwarts, and uses it about halfway through the book to identify [[spoiler: Nicholas Flamel.]] Nothing else on the card is useful until the ''very last book'', when Dumbledore's duel against Grindelwald is brought up again as an important point.
* Creator/MatthewReilly often re-uses plot devices. For example, in ''Scarecrow'', Knight revealed he was able to track Gant on his Palm Pilot because he hit her with a cloud of transmitting microdots. He used the same trick to track down Schofield. Mother saw this, and used his Palm Pilot to track down Schofield again.
* In Terry Pratchett's ''Literature/{{Nation}}'', Mau leaves an axe in a tree in the opening scene. After a tsunami knocks the tree into the ocean, he paddles past it in a canoe and feels [[GenreSavvy vaguely cheated]] when he can't pull the axe out. Then, in the final confrontation with the BigBad, he's unarmed, desperate, and hiding behind a sunken log. Guess which log it turns out to be...
* There's an enormously potent boomerang thrown at the end of ''Literature/TheHobbit'' in the shape of Bilbo Baggins' magic ring, which has the handy property of making its wearer invisible - naturally a Chekhov's Gun, as Bilbo is able to take advantage of this fact on a couple of crucial occasions before the end of the story. But then the ring pops up again unexpectedly some years later in ''Literature/TheLordOfTheRings''.
* ''Literature/TheWheelOfTime'':
** ''[[CoolSword Callandor]]''. It's the central MacGuffin of the third book, but soon after fulfilling prophecy by drawing it, Rand leaves it behind, and at the end of the fourth book he acquires the Choedan Kal, an even more powerful AmplifierArtifact. ''Callandor'' comes back in the eighth book, when he uses it against the Seanchan, but it turns out to be too dangerous to use, so he puts it aside again. Then, over the next few books, it's noted how odd that ''Callandor'' is central to the prophecies but the Choedan Kal are not even mentioned, [[spoiler:which leads Rand to destroy it]], and it's increasingly clear that Rand [[spoiler:and two women]] must use it in the Last Battle.
** The Bowl of the Winds is also a lesser example; it is a key plot point for much of books six and seven, is used to "fix" the weather in book 8, then mostly disappears. It makes a sudden reappearance in middle of the last book (14), being used to prevent the [[BigBad Dark One]]'s evil weather from flooding the good guys to death.
* In ''Literature/{{Daemon}}'', the Oberstleutenant Boerner bot was used to bring Loki/Gragg into the Daemon's circle around halfway through and isn't mentioned again until some way into the sequel ''Freedom''.
* In ''Literature/WarriorCats'', the [[spoiler: fox trap]] from ''Sunset''. First, [[spoiler: Berrykit loses half his tail in it.]] Then later, [[spoiler: it turns out to be instrumental to the villain's plot, ''and'' to beating the villain.]]
* ''Literature/LightAndDarkTheAwakeningOfTheMageknight'': One would think that the dagger given to Danny would only be used to locate other potential knights but it comes in handy not once but ''twice''. [[spoiler: Except the second time Danny realizes that it is not truly helpful.]]
* Lizzie in ''Literature/TheUnderlandChronicles''. In ''Gregor and The Code of Claw'', her talent with puzzles becomes incredibly useful.
[[/folder]]

[[folder: Live Action TV ]]
* One of the alternate names for this trope is from ''Series/BuffyTheVampireSlayer''. Olaf's Hammer was a hammer used by Anya's ex-husband, current troll god. It turned out to be the one thing the Scoobies had access to that could kick Hellgod ass.
** Also, Xander's knowledge from turning into Military Guy came up more than once. Although by the second time, he didn't remember as much.
** Buffy's rocket launcher turns up five years later for a FunnyBackgroundEvent.
* ''Series/HerculesTheLegendaryJourneys'' introduced the 'Hinds Blood Dagger', which had the power to kill Gods. The dagger served its purpose plot-wise, [[spoiler: Callisto brutally murders the God Strife with it]], and then Hercules [[spoiler: literally rams it into the stone stair rail of the Temple of Ares]]. It later reappears on HTLJ's spin-off XenaWarriorPrincess, and is the object of at least four characters desires over the course of two episodes. It is later used to threaten [[spoiler: Ares]] and [[spoiler: gut God-Callisto]] before being 'disposed of' for good.
* Some plot elements from ''Series/{{Lost}}'' might ''arguably'' fall into this category (although some fans will probably insist that ''everything'' on this show happens for a reason, and everything is planned out in advance). For example, in the season 1 finale, Jack, Kate, Locke and Hurley take several stacks of dynamite from the Black Rock and use some (but not all) of them to blow open the hatch [[spoiler:which leades to the Swan station.]] In the season 2 episode "Everybody Hates Hugo", Hurley wants to use the leftover dynamite to blow up [[spoiler:the Swan's food storage Room]], although Rose ultimately manages to change his mind. The dynamite is ''finally'' used [[spoiler:by Mr. Eko and Charlie in the season 2 finale, in a (futile) attempt to open the Swan's blast doors, which have been closed by Locke and Desmond to lock everyone else out.]]
** Crazy to see this dynamite as an example of coming back out of nowhere one season later, given that it was again explored at the END of the series, when Richard planned on blowing up the plane.
** The Dharma van in Season 3, which was originally the centerpiece of a filler episode. Most of the season went by without it appearing again, until it was shown in a flashback [[spoiler: to be the place where Ben killed his father]]. Then, in the season finale, [[spoiler: Hurley [[CarFu uses it to cause a distraction]] and save Sayid, Jin, and Bernard's lives]].
* ''Series/StargateSG1'' and its SpinOff ''Series/StargateAtlantis'' have very long memories, with many items you'd filed under ForgottenPhlebotinum ''years'' ago coming back.
** A good specific example is the Ancient communication stones: Introduced originally for a humorous clip show episode where a random schmuck finds out about the Stargate program through it, then used a season later to contact the Ori galaxy, and then used again in an Atlantis episode a few years after that.
*** And then it became a fundamental plot device in ''Series/StargateUniverse''.
** Another SG-1 example: the protagonists create a virus that will render a Stargate nonfunctional, and they use it on the Stargate of a planet owned by Ba'al. Demonstrating amazing knowledge of the Stargates' programming, he modifies it to spread throughout the whole Stargate network, shutting down every 'gate in the universe before they manage to reverse the effects. Then, a number of episodes later, they need to get an Ancient super-weapon working to wipe out the Replicators (who threaten to consume all matter in the galaxy), and it comes up that they need to figure out how to dial every Stargate in the galaxy simultaneously.
---> '''Jacob/Selmak:''' "I have no idea how to alter a Stargate to perform such a function. I don't know of anyone who can."
---> '''Sam:''' "I think I know someone."
** Another is the Quantum Mirror from "There but for the Grace of God" it is used a few seasons later to introduce an alternate universe Carter and [[ForgottenFallenFriend Kawalsky]] (killed off in the beginning of the series) for an episode. It is then referenced in season 9 as a possible solution for a problem they had encountered, but it had been destroyed.
* The healing machine introduced near the end of ''Series/BabylonFive'''s first season, and used 3 episodes later to revive Garibaldi. Then at the very end of the fourth season, someone uses it for a HeroicSacrifice.
* In ''Series/StarTrekTheNextGeneration'', the ''Enterprise's'' use of the deflector as a weapon seemed pretty nifty, even if it didn't work. You didn't expect this to become a standard trick in every subsequent series.
** A new shield enhancement that allowed a ship to fly into a star's corona was introduced as a mere plot device for a minor episode, but reappeared not long after in a major episode when they used it during a battle with the Borg.
* The new ''Series/DoctorWho'' uses this trope regularly, often to set up a dramatic scene for the season finale by introducing a concept earlier in the season.
** The two parter "Human Nature"/"Family of Blood" hinges on the Doctor's Time Lord self being concealed in a fob-watch. This reappears a few episodes later in "Utopia".
** One ''very'' persistent boomerang, even banging back and forth between ''Series/{{Torchwood}}'' and ''Series/DoctorWho'', is the Doctor's severed hand. After having been cut off the Doctor in "The Christmas Invasion", we see it in a jar for the entirety of the first season of ''Torchwood''. At the end of the season it starts pulsating, alerting Jack the Doctor is near. Just the moment you think it has served its purpose, bringing Jack and the Doctor together in "Utopia", the Master steals it along with the TARDIS at the end of the very same episode and then proceeds to use to grab the Doctor's genetic code and age him in "The Sound of Drums" and then even further in "Last of the Time Lords". After the Doctor defeats the Master you think the damn thing is finally done with, but no, it's pointed out to Donna and Martha in "The Doctor's Daughter", and takes the Doctor's regeneration energy after he gets shot and creates a copy of the Doctor that goes on to live with Rose Tyler in "Journey's End".
** In series 6, the Teselecta robot, which is controlled by temporarily-miniaturised humans and which can impersonate anyone, has an episode devoted to it. In the series finale, it cameos briefly among several of the Doctor's friends and enemies while he's researching the Silence to find out why he has to die. That's it, right? No! [[spoiler:The Doctor's dead body that burned in episode 1 was a Teselecta set to look like him, controlled by a mini Doctor who was "barely singed". So the Doctor's not dead after all.]]
** The Stasis Cubes in [[Recap/DoctorWho50thASTheDayOfTheDoctor "The Day of the Doctor"]], used to capture a single moment in time to make Gallifreyan artwork (it's BiggerOnTheInside). Okay, so the Zygons use it to get from England 1563 to 21st Century London. Used later with the Three Doctors when they need to get into the Black Archive to save Earth from [[EarthShatteringKaboom nuclear warheads buried underneath the Archive]]. And just when you thought you'd forgotten about it again and it's used up all its ammo, [[spoiler:the Doctors turn around and use it to ''save a freakin' planet''!!]]
* ''MyNameIsEarl'': Kenny, the first person Earl made restitution to after creating his list, has been made use of for his computer skills and working at a copy place several times since then. Once he got Earl, Randy, Joy, and Darnell jobs in an office by taking the computer literacy test four times - once for each of them.
* In one of the first few episodes of ''Series/{{NCIS}}'', it is established that Abby is fluent in sign language, since both of her parents are deaf. When she appears in the spinoff series ''Series/NCISLosAngeles'', she is kidnapped by a serial killer who streams live video of her online. He also gives her a paralytic that wears off gradually as the episode progresses, starting with her hands. As soon as she is able, she begins fingerspelling to the team, such as the fact that the door is booby-trapped. Luckily there's another signer on the team...
* Ted from ''Series/HowIMetYourMother'', was established as knowing sign language (to conveniently help/hurt Barney's claim that he was his deaf brother). This casually came up later, when he spoke to his ex's deaf boyfriend.
* The Eye of Jupiter that turned out to be significant in Season 3 of ''Series/BattlestarGalacticaReimagined'' was originally just one of many random pieces of artwork actress Katee Sackhoff had painted on the wall of the set of Starbuck's apartment for the Caprica arc in Season 2. Which is kind of spooky if you think about it...
* ''Franchise/UltraSeries'': The Magnerium Medicalizer was used by the Terrestrial Defense Force's Ultra Garrison to revive a crucified Series/UltraSeven, and was not used again until ''over 30 years later'' to save Series/UltramanMebius!
* [[WebVideo/AtopTheFourthWall Linkara]] recently pointed out the Zeo Crystal had been used like this in Series/MightyMorphinPowerRangers in the transition to Series/PowerRangersZeo. It was first introduced mid-season as a plot device to drive the conflict between the heroes and villains for a couple of episodes, and, knowing Power Rangers, you would expect it never to be used again, but, at the end of the season/transition between series, it comes back as a way to restore the Power Rangers to their adult forms and give them new powers.
** Unsurprisingly, ''Franchise/SuperSentai'' has versions of this, since its footage is used for Power Rangers. Nearly every series has had [[TheMovie a movie in theaters]], and in recent years there has almost always been an exclusive powerup of some sort introduced, either for the rangers, their mecha, and sometimes both. They would then later be remembered by the rangers arbitrarily at some point later in the season and used only once, maybe twice before its end. (Sometimes after its end with the teamup movies) The only series so far with repeated use of the movie powerup in-series is [[Series/SamuraiSentaiShinkenger Shinkenger's]] Kyoryuu Origami Disc.
*** Naturally, when some of these were translated to their respective American seasons, they ended up becoming ForgottenPhlebotinum instead. Though some of these were only used for finale arcs or teamups with explainations why they were unavailable before, justifying that status.
** Series/PowerRangersTimeForce, has the Electrobooster which is used for its function in the episode it is introduced, and then gets stored in the teams hideout where it comes back to play a part in the AllYourBaseAreBelongToUs finally.
* ''FatherTed'' uses this as a literal BrickJoke in the episode ''Speed 3'', a ludicrous spoof where Dougal will be blown up if the milk float he's driving goes under 4mph. After a brainstorming session with other priests proves fruitless, Ted uses Father Jack's pet brick (which he tripped over earlier) to weigh down the accelerator allowing Dougal to escape. After the bomb goes off after colliding with the evil milkman, Ted is knocked out by the brick as it plunges down from the sky. [[ItMakesSenseInContext Yes, it's that kind of show]].
* Midway through the ''Series/{{Covert Affairs}}'' episode "What's the Frequency, Kenneth?", Annie, sneaking into an office at the Smithsonian, notices a [[LaserHallway trip alarm]] and doesn't trip it. So you just know she's going to trip it as she sneaks back out, which of course, she does; doors slam shut, the whole works. At the end of the episode, she's running away from the episode's main villain... and leads him right into the same room, wherein he trips the same alarm.
* ''Series/BreakingBad'' has ricin. Walter created it early in season 2 in order to kill his psycho boss Tuco. It comes back later in season 4 when Walt attempts to do the same with Gus. [[spoiler: In the series finale, Walt finally successfully uses it to kill Lydia.]]
[[/folder]]

[[folder:Mythology]]
* OlderThanFeudalism: An example from Greek Mythology, starting with the Archaic ''Catalog of Women''. A boomerang on several levels: when Heracles (better known by his Roman name, Hercules) slayed the Hydra, he dipped his arrows in its poisonous blood thinking that SomedayThisWillComeInHandy. He winds up using it to kill a centaur named Nessos who meant to rape his (current) wife, Deianeira. Before he dies, though, the Nessos tells Deianeira to take his blood and use it as a love potion on Heracles, if the need should ever arise. She does so, and when she hears about Heracles' interest in the woman Iole, she anoints his clothes with it. The next morning, as Heracles burned sacrifice to the gods, the heat from the flames caused the Hydra's blood to eat away at his flesh, leading to his death. And then those arrows are used ''again'' by Philoctetes to mortally wound Paris during the Trojan War.
[[/folder]]

[[folder: Video Games]]
* ''Literature/{{Discworld}} II'': Everything from the pot of glue through the art of beekeeping to the continual theft of stuff from Mrs. Cake's house.
* ''VideoGame/TheSecretOfMonkeyIsland'': The root beer.
** ''VideoGame/MonkeyIsland2LeChucksRevenge:'' The voodoo doll.
** ''VideoGame/TheCurseOfMonkeyIsland'': The hangover cure and the crowbar.
** ''VideoGame/EscapeFromMonkeyIsland'': The Ultimate Insult, the gold-plated banana picker ("Hey, I get to use this [[LampshadeHanging more than once]]!").
** ''VideoGame/TalesOfMonkeyIsland'': The Feast for the Senses (In reverse the second time).
** Rule of thumb: If you're taught how to make one of something, you're gonna need at least two of it.
*** Case in point: You learn how to make a key in EdnaAndHarveyTheBreakout.
*** ''Tales'' has several minor others spread across the chapters: The Pyrite Parrot, [[spoiler:Guybrush's hook]], the Eye of the Manatee...
* The Cane of Pacci in ''VideoGame/TheLegendOfZeldaTheMinishCap''. You receive it early in the game, it helps for a while, it gets used less and less as you get further into the game and no truly new uses for it appear for quite some time...then all of a sudden, you need it again [[spoiler:in order to beat the FinalBoss]].
** Not all that uncommon in the other ''Zelda'' games, as the player's inventory can become rather stuffed.
** One of the more prominent examples is in ''[[VideoGame/TheLegendOfZeldaTwilightPrincess Twilight Princess]]''. Early in the game, Link, when talking to the mayor before leaving town, has to catch a runaway goat, stopping it in its tracks and throwing it to the side. This [[ChekhovsSkill later comes into play]] when Link is climbing DeathMountain (this time, against charging Gorons), and is even required to beat the mid-boss that he battles in the dungeon that follows immediately after climbing said mountain. This skill is pretty much forgotten about for the rest of the game, [[spoiler: until the battle against Ganon, where Link, in his Wolf form, must do this in order to expose his weak spot]].
* In ''VideoGame/SonicAdventure2'', the Mystic Melodies seem useless after doing the lost Chao missions, but some Hard Level missions require them for advancement.
** Also required in one case to get another upgrade. In fact, Security Hall almost seems like an aversion of the "You need the Mystic Melody to get the Lost Chao" rule until you remember that you needed the Mystic Melody to get the Treasure Scope, found in that very level, which ''was'' necessary to get the Lost Chao.
* In ''VideoGame/MegaManStarForce'', you get 5 cards to summon 5 Navis, each of which are used 3 times: after you get them, in the final area, and in an optional puzzle. Thing is, you may not realize the last one.
** Then there's the third game with Magnes' rocket. Launching it is the main objective of Echo Ridge Elementary's Science Club, and Luna 4 Prez gets caught up in it to secure votes for Luna. Once it gets launched, players tend to forget about it until the very end - where the same incident that almost caused the rocket to ''explode'' gave it the Noise resistance it needs to get close enough to Meteor G for Mega Man to jump from WAZA's Dynamic Station through the rocket into the Meteor Server.
* Numerous pieces of evidence in the ''Franchise/AceAttorney'' games show up in multiple contexts in the same case, or even pop up in multiple cases as {{Continuity Nod}}s.
** The Thinker Statue is used as the murder weapon in both case 1 and 2 of the first game.
** One example is [[spoiler:the metal detector]] from game 1, case 4, [[spoiler:which is originally used just to gather other evidence but makes a triumphant comeback in the courtroom, helping to finally nail the real culprit.]]
*** This then comes back in "Phoenix Wright: Trial and Tribulations" case 4 when [[spoiler:you use it to find the real murder weapon.]]
** In the first case of ''Phoenix Wright: Trials and Tribulations'', a major piece of evidence is [[spoiler:Dahlia Hawthorne's bottle necklace, which contains poison.]] When she shows up in the fourth case, the [[spoiler:poison in the necklace is used again by Terry Fawles.]]
** The fact that [[spoiler:a person's appearance changes during a channeling.]]
** [[spoiler:Trucy's Panties]] is used to object to testimony in the second case of ''Apollo Justice'' at least 3 times; [[spoiler:first to show proof of other crimes on the same night, then to show what the college student witness was hiding, and then, at the very end of the case, to prove why the car couldn't have been used to transport the body.]]? [[LampshadeHanging The judge even comments on Apollo's repeated presentation of that piece of evidence]].
** The Case 4 knife in ''Ace Attorney Investigations: Miles Edgeworth''. At first, it seems to be only significant because of its status as a murder weapon, but before the end of the case it's revealed to be [[spoiler:doubling as a missing piece of evidence, the Yagatarasu's Key]]. Shortly after, it's stolen by [[spoiler:the murderer]], who escapes. End of the story, right? Wrong. It shows up again in Case 5 (seven years later), [[spoiler:in the possession of that case's first murder victim, Manny Coachen]]. The full significance of the item is eventually revealed: [[spoiler:the key end opens the safe in his office, while the "knife" portion is used as a secondary key to open a secret compartment in the safe.]] But we're still not done; later on, [[spoiler:when the murderer--Quercus Alba--is being confronted by Edgeworth, it comes to light that he likely struggled with Manny Coachen, and Manny fought back with a sharp stabbing weapon of some kind--one that had somehow been concealed in a way to avoid detection. Guess how Manny pulled it off. That's right, he used the Yagatarasu's Key as a knife, as his compatriot had done seven years before.]]
* In ''Neoquest II'', an RPG in ''NeoPets'', the sword you start off with is also the best sword to use against the final boss.
* Paula's Pray ability in ''Videogame/EarthBound'' starts as a useful, if unpredictable skill, that takes a back seat to her more reliable psychic powers. [[spoiler:Then you need to pray for a chance of beating the final boss.]]
* ''VideoGame/ChronoCross''. Oh, ''VideoGame/ChronoCross''. There are ''party characters'' that serve this purpose.
** Before that, Melchior in ''VideoGame/ChronoTrigger'' is an example of this with a ChekhovsGunman: He first appears to just be some random merchant, then it turns out he's the forger of the Masamune, and then he turns out to also be [[spoiler:one of the three gurus of the ancient age of magic]].
* While most spells in ''VideoGame/{{LOOM}}'' are used only once, a few get used more than once - especially the opening spell.
** Sometimes, you use a spell, and later you'll have to cast the same spell ''backwards'' to obtain the opposite effect (e.g. open/close)
*** Loom is a particularly interesting example because there are no items in the game. Most adventure games that require a character to use a 'recipe' for something give that character an item that lists the recipe, so you can turn back to it if you get stuck. In Loom, you have to write the spells down as you find them out, or you are screwed (unless you use a strategy guide, which generally wasn't possible in those days). And even a strategy guide might not help, since some of the spells are randomized for each playthrough.
* In ''VideoGame/MegaMan2'', the Bubble Lead is pretty much useless against every other enemy in the game... until you get to Wily's [[spoiler: Hologram]], in which it's the only weapon that causes actual damage to it instead of ''healing it to full'' like every other weapon.
** In ''VideoGame/MegaMan3'', the Top Spin is used once against a boss like all the other weapons, and then, it being the worst attack in the history of Mega Man, you probably never use it again...which is a shame, because the final boss goes down with one hit of it.
** The Rolling Shield from ''VideoGame/MegaManX'' is a bit unwieldy in regular gameplay, but it's the only special weapon that can damage Sigma's second form. Otherwise, you're stuck with charged X-Buster shots.
* ''FullThrottle'' does this. It's a game about a GeniusBruiser [[AllBikersAreHellsAngels biker]]. The extremely useful item in question? A tire iron.
** It might even go so far as to be Chekov's Yo-Yo. You use it, then again, then again, then ''again'', then '''''again'''''...
* ''VideoGame/TheDig'' has a shovel serve as the puzzle solution 10 separate times. At one point the main character even [[LampshadeHanging comments]], "What if I hadn't brought this shovel along? No, that's not worth thinking about."
* In ''{{Halo}}'', the Master Chief has to get the Index to activate the ring and destroy the Flood. In the very last moment Cortana takes the Index away and prevents the destruction of half the galaxy. In the end of Halo 3 [[spoiler:the Flood has taken control of a massive space station far outside the galaxy, that serves as the control room for all the Halos in the galaxy and creates new rings if any ones are destroyed. With an almost completed ring inside the station, everything needed would be an Index to activate it. ''"I'm a thief... but I keep what I steal."'']]
* The Sword of Gith in NeverwinterNights2 is the only weapon that can kill the King of Shadows, the BigBad of the first campaign. In the second campaign, it is also the key to the Betrayer's Gate.
** [[FridgeLogic ...Completely ignoring the fact that Gith had nothing at all to do with the Betrayer's Gate, of course.]]
** Which means nothing as the sword has had many owners since Gith, one of them simply used it for the key in the gate they made.
* In ''GrimFandango'' it's very easy at times to forget you have a scythe.
** ''GrimFandango'' has so many guns lined up on its narrative mantelpiece that it probably crosses the line into ChekhovsArmoury. At least one is actually a boomerang: Near the start of the game, the player learns of the two strange properties of the DOD's packing foam, and not too much later, uses one of them (that it expands like crazy when the two types are mixed.) Hours and hours later, nearing the end of the game, the player needs to remember the other property: [[spoiler:that it combusts if sprayed by a certain type of chemical fire extinguisher.]]
** Another boomerang can be launched in Year 2 by examining a cabinet in Toto Santos's scrimshaw parlor, which causes Toto to note that he should remember to restock liquid nitrogen. In Year 4, Manny steals a bottle of the chemical from Toto in order to freeze the gelatin covering a booby trap (long story). After that, near the very end of the game [[spoiler:Manny uses what remained in the bottle to get rid of the flower on his chest after getting shot with a sproutella dart]]. Toto does specifically mention that he uses the stuff as a ''pain killer''...
** Glottis's capability of drinking entire barrels of (preferably alcoholic) beverages, also introduced in Year 2 and already used shortly after its introduction, comes back as a part of the abovementioned boobytrap puzzle. Glottis hangs a lampshade on this, complaining that his stomach doesn't stretch like it used to back then.
* In ''[[VideoGame/{{Hitman}} Hitman: Blood Money]]'', at one point you have to use a death serum to rescue a fellow agent by faking his death. In the final mission [[spoiler:you use it again to fake your own death in order to kill the true BigBad behind the whole plot against you]].
* Done twice in ''VideoGame/{{Portal}}''. First, at the end of the CompanionCube level, you have to [[spoiler:throw your Weighted Companion Cube into the Aperture Science Emergency Intelligence Incinerator to finish the level.]] Then, near the end of the game, one puzzle requires you to [[spoiler:manipulate a rocket-launching turret into breaking glass. Both the incinerator and turret appear a second time in the final boss room and are crucial to winning the battle.]]
** An example of good game design theory. [[spoiler:The earlier uses of the incinerator and rocket launcher teach the player, setting up for their combined use in the boss fight.]]
*** In fact, the commentaries for many of the ''Half-Life'' games mention this style of game design. Show the player something, let them do that something, and then let them do that something while in a dangerous situation. Generally there isn't as much lag between the intial teaching and the usage of that skill, but it sorta counts.
** The [[VideoGame/{{Portal2}} sequel]] has another example: near the beginning, you trick the system responsible for throwing out defective turrets into throwing out working ones and keeping the defective ones. Soon afterwards, GLaDOS throws turrets at you - which are defective. [[spoiler:Near the end of the game, Wheatley sets up an [[StupidityIsTheOnlyOption obvious death trap]]... full of defective turrets.]]
** ''Portal 2'' is a game where nostalgia fights to create an unrelenting march of Chekhov's Boomerangs, all while introducing new ones.
* Goldbob in the second ''VideoGame/PaperMario'' game qualifies. After first appearing as a spectator in the Glitz Pit of no apparent importance, he and his family are fellow passengers on a train to Poshley Heights, where an incident surrounding the family serves as a BrokenBridge sequence. Later in the game, Mario is told that Goldbob has some sort of importance in a Bob-omb colony in the frigid wastelands and needs Goldbob's permission to use a special cannon.
* In ''[[VideoGame/ChzoMythos 7 Days a Skeptic]]'' you use the [[spoiler:wrenches]] more than once.
** And in the previous game, you were forced to use the "Salty bear on a stick" trick more than once. No, seriously.
* In ''[[VisualNovel/FateStayNight Fate/stay Night]]'', this occurs with Caster's Noble Phantasm Rule Breaker. First used in the Fate scenario to control Saber (thus leading to a Dead End). Then in Unlimited Blade Works [[spoiler:used in Archer to break his contract with Rin, letting him fight Shiro]] and then again in Heaven's Feel [[spoiler:when Shiro traces the Rule Breaker and uses it to break Sakura's connection with Angra Mainyu]]
* This goes all the way back to 8-bit videogames: in the Gargoyle Games' graphic adventure ''Marsport'', one puzzle involves baking a cake. A later puzzle ''apparently'' involves baking another cake -- but this turns out to be no longer possible. It transpires that the real solution to the second puzzle is to just use the same cake as before.
* The [[spoiler:birdseed]] in the third episode of ''VideoGame/WallaceAndGromitsGrandAdventures'' is used for 3 separate puzzles.
* In ''{{Uncharted}} 2: Among Thieves'', Nathan Drake finds an oil lamp made of a combustible resin, used to uncover a hidden map. This resin becomes important later on when it is realized to be the [[spoiler:the sap of the Tree of Life]] and is subsequently used to defeat the FinalBoss through its combustible properties.
* ''VideoGame/GodOfWar'' has [[spoiler:Pandora's box]]
* In ''WildArms'' Cecelia's Tear Drop item comes back several times.
* ''VideoGame/DragonQuestVII'' has a couple examples.
** Early on in your quest, you meet the FortuneTeller Pamela, and help her out when her CassandraTruth falls on deaf ears. After several adventures, you abruptly learn she has the knowledge required to fix ''another'' problem you've run into: [[spoiler: curing a victim dosed twice by the Gray Rain, which is in and of itself a bit of a Boomerang]].
** The best example, however, is [[spoiler: the Empty Bottle you obtain after using the Holy Water]]. This sits in your inventory after its first use and is easily forgotten, until you need to use it to [[spoiler: collect some ''other'' special water]]. Notably, you can do this long before finding out it's required.
* VideoGame/DragonQuestVI has a few as well:
** The Dream Dew. Used to allow people from the "upper"[[note]]for lack of a less-spoilerific term[[/note]] world, like TheHero, to be visible to people in the "middle" world. [[spoiler: You and your Boisterous Bruiser friend are not the only ones that need it...]]
** The franchise-famous Mirror of Ra is needed to expose [[DiscOneFinalBoss Murdaw's]] deceptions [[spoiler:as well as trigger a later quest involving a mirror prison]].
** A more innocuous one is the golden pickaxe: used to break up rocks in a mountain cave [[spoiler:''and'' some floorboards guarding an Armor of Plot Advancement]].
* In ''SuikodenV'', you first use the sluice gates at the ruins near your castle to break out a flood to destroy the Godwin dam and bring back water to Lordlake. After awhile you seemingly forget it because of a series of events, including abandoning your castle from your enemies, until Lucretia tells you to go back to the ruins and open up the sluice gates again to ''flood'' the caste.
* VideoGame/BrokenSword: Shadow of the Templars has the manhole-opening tool.
* In ''{{Avernum}} 2'' and ''3'', you get an ability called "Ritual of Sanctification" for a specific quest in each game. (It's used to purify an evil altar.) You can use it several more times throughout each game, and at least once it's needed to complete another quest.
* In ''VideoGame/MetalGearSolid3'', Big Boss begins the second and main storyline with two pieces of nifty but largely useless equipment, a suicide pill and an antidote which can be strategically used to play dead. As the player gets better camouflage packs and weapons it becomes less and less useful to the point where the player has no real need to use either until a certain boss fight later [[spoiler:where Big Boss is killed while in the world of the dead and the player has to use the antidote to 'wake up' to progress in the game.]]
* In ''VideoGame/ProjectXZone'' after the prologue and you're on the first chapter, while [[OriginalGeneration Kogoro and Mii]] discuss on what their next move will be, [[VideoGame/StreetFighterII Chun-li]] and [[VideoGame/{{Darkstalkers}} Morrigan]] come out of the fountain after their escapades in the fifth prologue. For quite awhile, you don't get to visit the Koryuujii estate until much later [[spoiler: when Oros Prox invades Mii's home. A ''few chapters'' after that when the party decides to return to said estate, it turns out there's ''an underground passage located underneath the fountain''. It turns out it's the Oros Prox's ''base of operations''.]]
* ''VideoGame/DragonAgeII'': The red lyrium idol Hawke and Varric steal from the Primeval Thaig in Act 1 [[spoiler: glows ominously as Varric's brother Bartrand locks them into the thaig to die.]] It shows up again in Act 2 [[spoiler: where losing it has now driven Bartrand insane]] and again in Act 3 [[spoiler: where finding it has driven Meredith ''more'' insane.]]
* ''VideoGame/StrongBadsCoolGameForAttractivePeople'': In the last part of the game, "8-Bit is Enough," you use a key to open the arcade cabinet towards the very beginning of the game. At the end, [[spoiler: in the final dungeon of the mainframe after beating Ultimate Trogdor,]] you are faced with a locked door as the dungeon crumbles around you. Guess which key opens it.
* In ''VideoGame/ABoyAndHisBlob'' (the original), the Apple Jack jellybean is used to lift off the manhole cover and escape from the sewer. [[spoiler:It's used again at the very end of the game to defeat the emperor.]]
[[/folder]]

[[folder:Webcomics]]
* In ''Flying Man and Friends'', the main characters move into a house they "found" early on in the series. Five months later, the comic finally addresses who the house originally belonged to ([[http://www.flyingmanandfriends.com/?p=302 a platypus named Platy]]).
* While Pete Abrams of ''SluggyFreelance'' seems positively CrazyPrepared with all those [[ChekhovsGun Chekhov's Guns]] he has hidden all over the place, we can safely say he certainly didn't plan the part about the man who sold [[KillerRabbit Bun-bun]] to Torg in the first place and who was shown in one panel talking on the phone and saying there would be no refunds. ''Nine years later'' it's revealed [[spoiler:that he was actually the supernatural being known as Uncle Time, as Bun-bun's ending in Torg's "possession" was shown as the culmination of a story involving rather convoluted time travel elements.]] Even the squiggle on his shirt gained significance.
* In ''Webcomic/TheOrderOfTheStick'', Belkar aquires a Ring of Jumping. This first allows him to [[spoiler:escape his cell in Azure City,]] then later he lends it to Roy, who uses it to [[spoiler:jump on the back of a flying dragon and fight the Big Bad. And get himself pointlessly killed.]]
** Vaarsuvius learns the [[http://www.giantitp.com/comics/oots0842.html consequences]] of using [[http://www.giantitp.com/comics/oots0639.html a certain spell]].
* {{Sinfest}}: Glitter points really come in handy a lot.
* When they're not {{Brick Joke}}s, ''Webcomic/{{Homestuck}}'' is full of elements that are used and then unexpectedly get reused later. This even applies to [[ChekhovsGunman characters]].
[[/folder]]

[[folder:Web Original]]
* The Literature/WhateleyUniverse authors love Chekhov's Gun and foreshadowing enough that this is getting pretty common. The way a blackmailer got a note past magical wards and into Poe Dorm comes back later as the way someone gets a tracker in Fey's luggage so she can get ambushed at Christmas. The Hawthorne girl in a Carmilla story who has toxic blood? She turns out to be Phase's cousin, who shouldn't even ''have'' mutant powers. Or the way that Counterpoint's power mimic ability works. Or Phase's little trick stealing Generator's underwear ''while she is wearing it'' keeps coming back. There's a ton of them.
* In the very first [[GlobalGuardiansPBEMUniverse Global Guardians]] story, Dogfight's status as a husband and father is remarked on by his teammates, as it is relatively rare for costumed crimefighters to be married, much less to be married with children. Years later, when Dogfight is [[HeroicSacrifice killed rescuing people]] from the World Trade Center during the September 11th attacks, his family is brought front and center to add a bit more poignancy to the memorial for the attack's victims. They then disappeared into the background, presumably never to be seen again. In one of the last Guardians stories, Dogfight's oldest son reappears as a supervillain (having inherited his father's powers) seeking revenge on the Guardians, whom he blames for his father's death.
* In ''Series/{{Noob}}'' Sparadrap's hacked staff is one. He got it in Season 1, the fact it's overpowered and a present from Tenshirock is discovered in Season 2, at the end of which it gets BroughtDownToNormal. In Season 4 finale, Tenshirock reactivates the plan that made the staff overpowered, right around the time Sparadrap ends up fighting someone against whom he probably wouldn't stand a chance with the staff in "normal" state. Something similar happens in Season 5 finale.
[[/folder]]

[[folder:Western Animation]]
* An episode of ''TheSimpsons'' has Marge buying an impossibly absorbent paper towel brand and becoming enamored with its mascot. This seems to be just a [[HalfwayPlotSwitch setup for Homer and Bart to pull a prank on her, and apologize by going to a magic show that uncovers repressed memories of Homer finding a corpse in a quarry when he was a kid]], but she then used the towels to drain the quarry of water so they can find the body.
** ''TheSimpsons'' actually uses this trope a lot, as a consequence of HalfwayPlotSwitch structure.
* A lot of the stories in ''DonaldDuck & Co.'' works with a ChekhovsBoomerang returning in the end and solving the plot.
* This is a common usage in ''WesternAnimation/DannyPhantom''. Nearly every Fenton invention will be used at least twice in the show, especially if it's unexpected. Special bonus points for one of the weapons for being an actual boomerang!
* Torgo's Executive Powder from ''WesternAnimation/{{Futurama}}''. It's got a million and one uses.
** And again more recently with Professor Farnsworth's "Disintegration" (actually teleportation) Ray.
** In "Leela's Homeworld", the professor's nose-making machine is later used to translate the message that was with Leela when she was abandoned as an infant.
---> '''Fry:''' "Isn't that the machine that makes noses?"
---> '''Professor Farnsworth:''' "It can do other things. Why shouldn't it?"
* In an episode of ''WesternAnimation/BatmanBeyond'', one of Mr. Freeze's ice ray guns comes in handy against a villain who can turn into liquid.
** Old man Wayne actually pulls useful equipment from his gallery several times, such as his old utility belt when the current Batsuit gets corrupted, or the Grey Ghost's hat and goggles when he needs to hide his identity. It's awesome.
* Occurs several times in ''[[WesternAnimation/TeenageMutantNinjaTurtles2003 TMNT 2k3]]'', most notably in the episode "Same as it Never Was" in which the [[ThisIsADrill Turtle Tunneler]], which had been introduced in the previous season as part of a different subplot, is used to kill an alternate version of the Shredder.
* Zuko's broadswords in ''WesternAnimation/AvatarTheLastAirbender''. Most viewers are under the impression that the gun was on the mantelpiece (literally), it was used once, and that was that. But he ended up using it almost as much as firebending and it changed the course of the series many times.
** Katara's necklace also qualifies. After Zuko ends up with it, and he unsuccessfully tries to use it to force Katara into helping him, you think its purpose is over. Then they reach the Northern Water Tribe, and its real point in the story arc shows itself.
** Aang's bison whistle.
** And then there's Sokka's actual boomerang. It makes repeated appearances throughout the show, usually for comedic purposes... then it makes one final [[TearJerker emotionally-charged]] appearance in the show's finale, just when you were least expecting it.
* In an episode of DextersLab where Dexter has to combat an alien life form that's possessed all his family members, he use's one of his self-manned robot inventions that he used previously to combat a group of bullies harassing him with dodge-balls even stating "I haven't used this baby since that whole dodge-ball incident".
* ''WesternAnimation/SouthPark'':
** In the episode "Crippled Summer", after repeated failures to sabotage Jimmy's team, Nathan (the leader of the rival team) attempts to rig Jimmy's ukulele to explode, but it ends up used as an XylophoneGag (since Nathan's plotline is a DeconstructiveParody of ''WesternAnimation/LooneyTunes''). After the ukulele blows up in Nathan's face, everything involved in Nathan's previous plans come back to attack him again -- a black mamba snake bites him, Tardicaca Indians shoot him with arrows, and a Tardicaca shark rapes him.
** In the episode "200," every celebrity/famous figure that has been on South Park is back in this episode. Tom Cruise, Barbara/Mecha Streisand, Mel Gibson, Bono, Paris Hilton, R. Kelly, Sally Struthers, you get the point. They're ALL back to sue the town..
* [[TheFairlyOddparents Timmy Turner]] uses his magical time-traveling scooter several times during the series. He also somethings uses other magical items more than once
* WesternAnimation/MyLittlePonyFriendshipIsMagic: Pinkie's "Pinkie Sense" returning in Season 2's "The Mysterious Mare-Do-Well" and "It's About Time" from Season 1's "Feeling Pinkie Keen".
* ''WesternAnimation/SuperRobotMonkeyTeamHyperforceGo'' has the "Pit of Doom". The first time it becomes important after its introduction (in Season 1) is when it becomes the location of [[spoiler: Mandarin's cloning factory]] in Season 2. But in the Season 2 finale, it's revealed that Skeleton King's ''real'' intention for building it all along was to [[spoiler: reach the egg of the Dark One embedded inside Shuggazoom to awaken it, hatch it, and unleash it on the rest of the universe]]. And at the end of Season 4 it becomes the place where [[spoiler: Skeleton King is resurrected]].
* The Talismans in ''WesternAnimation/JackieChanAdventures'' pop up several times after the first season.
* In ''WesternAnimation/TeenageMutantNinjaTurtles2012'', we see that Baxter has collected a lot of mutagen in a giant vat in his lab. By the end of the episode, someone ([[spoiler:Dogpound]]) falls in. In two later episodes, we see he still has it, and in each case, another character ([[spoiler:April and Karai]]) falls in as well.
* The second episode of ''WesternAnimation/SonicBoom'' has Eggman's kazoo, which he uses during the board game. Later, while [[spoiler: Eggman's mech attacks the lair,]] Eggman uses said kazoo to wake up Sonic and Tails to activate the two killswitches at the same time.
[[/folder]]
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