History Main / ChekhovsBoomerang

** 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.

* 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.

* 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.

* [[WesternAnimation/TheFairlyOddparents Timmy Turner]] uses his magical time-traveling scooter several times during the series. He also sometimes uses other magical items more than once. (Including some that exploded two episodes earlier like the Shrinking Robosuit, but who cares...)
* Torgo's Executive Powder from ''WesternAnimation/{{Futurama}}''. It's got a million and one uses.

* 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''.
** Gollum is a living Chekhov's Boomerang. First, he (unintentionally) supplies Bilbo with the all-important Ring in ''Literature/TheHobbit''. When he fully reappears in ''Literature/TheLordOfTheRings'', he [[spoiler:leads Frodo and Sam into Mordor before betraying them to Shelob, leading to Frodo's capture and Sam's brief turn as Ringbearer]]. He disappears again after that, only to reappear just as [[spoiler:Frodo reaches Mount Doom and decides to claim the Ring for himself instead of destroying it. Gollum attacks him and finally retakes the Ring, but during his victory dance, both he and the Ring end up toppling into the Fire.]]

** 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''[[Literature/HarryPotterAndTheChamberOfSecrets Chamber of Secrets]]'' 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]].

* ComicBook/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.

* In an episode of ''WesternAnimation/DextersLaboratory'' 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".

* A lot of the stories in ''DonaldDuck & Co.'' works with a ChekhovsBoomerang returning in the end and solving the plot.

* 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.* 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.

* In ''Manga/{{Heroman}}'' Joey activates [[spoiler:Heroman's Augment ability in Episode 4]]. [[spoiler:Fast-forward 19 episodes later, and it is used [[SugarWiki/MomentOfAwesome to spectacular effect]]]].

* ''Manga/PokemonAdventures'' manga.
** [[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 Hideout" 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 ''Manga/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 [[SugarWiki/MomentOfAwesome 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.]]
* ''Manga/NegimaMagisterNegiMagi'' has one that crosses continuities; an antagonist attacks Negi using an attack that originated in Creator/KenAkamatsu's previous manga ''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.]]
* ''Anime/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.

** A good example: Ace's tattoo. Looks misspelled, right? Well after his introduction, during the Marinford arc, we find out [[spoiler: the crossed out S was the jolly Roger of his and Luffy's third brother, Sabo, who died.]] Then hundreds of chapters after ''that'' we find out [[spoiler: Sabo actually lived but with amnesia, and only reading about Ace's death at Marinford brought back his memories before putting him in a coma, and he later shows up to help Luffy.]] So what looked like a little quirk in a character's design in the Alabasta Saga was really foreshadowing for something in the Dressrosa saga, well over ''four hundred chapters later.''
** Even the villains of previous arcs get this treatment by Oda. Notable examples include [[spoiler: Buggy, Mr 2, Mr 1, Blackbeard, and even '''Crocodile'''. Caesar as well, even though he was defeated in the Punk Hazard Arc, he proves to have a pivotal role upto the Whole Cake Island Arc.]]
* ''Manga/{{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.
* The Ultra Sacred water (presumably the water from the Garlic Junior arc of ''Z'', and not similarly named waters from ''Dragon Ball'') in ''Anime/DragonBallGT'', which was useful to get the characters cured from Baby's control.
* Remember that time way back near the beginning of ''Anime/MagicalGirlLyricalNanoha'' where the heroine used a little spell called "Area Search?" Well, in ''Anime/MagicalGirlLyricalNanohaStrikers'', 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.]]]]

* 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.]]
* ''Anime/MobileSuitGundam00'': 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/TheFamiliarOfZero'', 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 ''Anime/StarBlazers[=/=]Anime/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).

* ''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/NyarukoCrawlingWithLove'', 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 there’s 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 Cole’s 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, Ciel’s 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 Aloise’s soul]] the same way Ciel’s 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.
* ''Manga/RaveMaster'':
** In volume 6, when Haru is facing down Sieg, he's briefly able to get past his magical defenses by using the Eisenmeteor form of his sword, having realized that magical defenses only work on magic-infused items. Much later, Sieg is facing down Haja the Infinite, who has unlimited magic power. Unable to beat Haja with sheer magic strength, he instead rams him through the heart with a staff devoid of magic, having remembered what Haru said and realizing that Haja would be unable to block it.
** During the fight with Orge, Musica is able to neutralize one of his goldclaimer techniques, pointing out the basic alchemy process between metals is all the same with the only difference being power. In vol. 32, when Musica attempts to forge a new blade for Haru's Ten Powers sword, he remembers that instance and instead uses his alchemy powers to make the blade instead of trying to master swordsmithing in a short time.
* ''Manga/FairyTail'':
** Shortly after the end of her [[DayInTheLimelight arc]] we find out that Erza, who we saw in an earlier chapter losing 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.
** At the end of the Tower of Heaven Arc, Natsu first uses his [[SuperMode Dragon Force]] by devouring the highly-concentrated magical energy of the Etherion crystals to defeat Jellal. At the climax of the Nirvana Arc, Jellal, now an amnesiac good guy who vaguely remembers the events of said arc, gives Natsu a power up in the form of his remaining magical energy in a powerful flame spell so Natsu can use Dragon Force again to defeat Zero. Then Sting and Rogue at the climax of their fight in the [[TournamentArc Grand Magic Games]] reveal they can use Dragon Force without an outside source. ''Then'', in the Tartaros Arc Wendy remembers how Natsu activated Dragon Force and replicates it via absorbing the high ethernano concentration in the air around [[TheMagicGoesAway Face]] to activate her own version and fight [[OurDemonsAreDifferent Ezel]], while Natsu manages to tap into Dragon Force against Mard Geer without an outside source of energy on his own. Finally, during the final arc Wendy reveals she can use Dragon Force naturally after training, Gajeel obtains it by absorbing the Demon Barrier Particles of Bloodman, and Natsu once again uses it without outside help to help defeat [[BigBad Zeref]].
** At the climax of the Tenrou Island Arc, Natsu unlocks Lightning-Flame Dragon Mode when fellow Dragon Slayer Laxus gives him his magic to fight Hades. During the Grand Magic Games, Gajeel remembers this and chooses to replicate it while fighting Rogue's SuperPoweredEvilSide to obtain Iron Shadow Dragon Mode. ''Then'' [[spoiler:the Rogue from the BadFuture reveals he unlocked his own dual mode via killing and devouring his best friend Sting's magic to obtain White-Shadow Dragon Mode.]] Finally, in the Alvarez Empire Arc, Rogue replicates what Gajeel did to him to let Sting obtain White-Shadow Dragon Mode to fight Larcade of the Spriggan 12, [[spoiler:which serves as a fitting ironic twist to what happened to their future counterparts.]]
** In the Tartaros arc, it's revealed [[spoiler: Igneel and the other dragons used the Dragon Soul technique to enter the Dragon Slayers' bodies to both protect them and to extend their own lifespans after being fatally injured long ago by Acnologia, thus explaining their long disappearance.]] In ''Anime/FairyTailDragonCry'', the BigBad Animus is revealed [[spoiler:to be a dragon that used that same technique to save himself and a dying Sonya after he was fatally injured by Acnologia, but because Sonya wasn't a Dragon Slayer he couldn't free himself like they could, which is why he sought out the [[MacGuffin Dragon Cry]] to give himself the power to free himself from her body.]]
** The FinalBattle is ultimately won through the reuse of one-off techniques:
*** The Sirius Island arc introduces two spells: Fairy Sphere, a defensive spell that Mavis seals Fairy Tail inside to protect them from Acnologia on Sirius Island; and Magilty Sense, Merudy's signature magic, which she reveals earlier in the final arc can multiply other people's power. Incidentally, both spells require a deep, emotional bond between others to be properly cast. [[spoiler:Lucy--one of the most empathetic characters in the series, as noted in ''Anime/FairyTailTheMoviePhoenixPriestess''--figures out that they can use Fairy Sphere to [[SealedEvilInACan seal Acnologia away]], and Merudy uses her Magilty Sense to link Lucy with every wizard on the continent to power the spell.]]
*** Wendy picks up on Irene's ability to enchant other objects and people with her own magic to get out of a BodySwap and power up Erza's sword. [[spoiler:When faced with Acnologia's disembodied soul, Wendy uses this technique to [[AllYourPowersCombined transfer her and the other Dragon Slayers' magic into Natsu]], which proves to be [[PhlebotinumOverload more magic than Acnologia can handle]] when Natsu slams all of it into him at once while he's paralyzed by Fairy Sphere's activation.]]

* ComicBook/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.

* ''ComicBook/XMen'': 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 one ''ComicStrip/{{Peanuts}}'' arc, Charlie Brown in lost in the woods, so Peppermint Patty and Marcie go out to look for him. Marcie brings supplies, including cold weather gear, food, water, [[ArsonMurderAndJaywalking and comic books.]] Eventually, it starts to snow, and because Patty is only wearing her sandals, her feet get cold. So Marcie tries to wrap her feet in the comic books. It works for a while, but eventually, the storm gets worse, and the hastily made comic bandage starts to fall apart. Fortunately, when the blizzard is at its worst, they find Charlie Brown and Snoopy, or rather they find them; they followed the trail of comic book pages.

* The ivory pipe in ''Film/NationalTreasure''. It's almost a Swiss Army MacGuffin.

* Doug's statue-impaled mattress in ''Film/TheHangover''.

* ''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]].

* 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.
* William Cage, the protagonist of ''Film/EdgeOfTomorrow'' observes a soldier strapping a claymore explosive to himself prior to going into battle as if preparing for a TakingYouWithMe scenario. A few scenes later, the mine ends up used (albeit not by the same soldier) for exactly that purpose against a charging alien. The ChekhovsGun fired, most in the audience will forget about it after that. Only, because of the GroundhogDayLoop nature of the film, the mine reappears later, strapped to the same soldier as before, and is used for another TakingYouWithMe moment against a wave of charging hostiles.
* ''Film/OddObsession'': The insecticide and cleanser cans. One's in a red can and the other's in a green can, and it is established that Hara is color-blind and can't tell the difference between cans. Hara decides to [[InsaneTrollLogic switch the contents of the cans so that she doesn't mix them up]]. What happens? Well, Tomiko decides to kill her mother and her faithless fiancé, so she does their tea with poison -- except that the poison is actually the cleanser, so all she does is give their tea a funny taste. However, it turns out that in addition to illogically switching out what's in the cans, Hara also quite logically marked the poison can with "poison" on the bottom. After looking at the bottom of the can and confirming that it is in fact poison, Hara dumps it on top of the salad, and thus murders all of the other three.
* Vijay's "786" badge in ''Film/{{Deewaar}}''.
** First, it saves him by [[PocketProtector stopping the bullet]] when he's shot by one of Samant's men while stealing the gold back.
** Later, it saves him when Samant's men try to assassinate him. Anita notices that he left it on the bar counter, and rushes after him to return it. She drops it and they both go to pick it up right when Samant's men fire, causing the shots to miss them both.
* Subverted in ''Film/AQuietPlace'' with the nail sticking out of the basement stairs, which Evelyn steps on. Later in the movie when the characters go back down the stairs, there's a closeup showing that the nail is still there and uncovered. However, it never comes up again.

* ''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.]]
* Creator/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.

* 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 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...

* ''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, and also gets used by another character during a key battle in the ninth, but it turns out to have a flaw that makes it seem too dangerous to use [[spoiler: unless you're willing to let two women link with you]]. 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 the male Choedan Kal]]. Ultimately, it's precisely the "flaw" in Callandor that makes it necessary; [[spoiler: it allows Rand, Nynaeve, and Moiraine to hijack Moridin's link to the True Power and [[HoistByTheirOwnPetard Hoist the Dark One by its own Petard]]]].
** 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 fox trap from ''Sunset''. First, 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.]]

* Lizzie in ''Literature/TheUnderlandChronicles''. In ''Gregor and The Code of Claw'', her talent with puzzles becomes incredibly useful.

* In Rhys Bowen's ''Heirs and Graces'', Sissy's beautiful chiming clock [[spoiler: is first significant because it runs slow. Then at the climax, Sissy saves Georgiana's life by throwing it at a would-be murderer.]]
* In ''[[Literature/OldMansWar The Ghost Brigades]]'', protagonist [[SuperSoldier Jared Dirac]] discovers that his [[{{Nanomachines}} [=SmartBlood=]]] can be remotely instructed to spontaneously oxidize (i.e. combust), first observing this in training when it kills a mosquito that tries to drink from him. [[spoiler:Later on, it saves his life when he blinds an enemy combatant by spitting [=SmartBlood=] into its eye-analogues and igniting it; then at the book's climax, when the BigBad tries to perform a GrandTheftMe, Jared counters him by [[TakingYouWithMe combusting all the [=SmartBlood=] in his body.]]]]
* In ''The Book of Three'', the first of the ''Literature/TheChroniclesOfPrydain'' series, Taran encounters and nurses a baby gywthaint (a hostile bird species enslaved by the BigBad) back to health. Most readers saw an AndroclesLion moment coming, and were unsurprised when it repaid the favor at the end of the book. It was then probably forgotten about, making its return [[spoiler:and HeroicSacrifice]] in the final book all the more shocking.
* ''Literature/CastleHangnail'':
** Early in the book, Molly tries to solve a problem involving a donkey by adapting a spell that was designed to be used on cows. As the story progresses, she solves several more problems by using the same spell again, each time on a different kind of animal and never on an actual cow.
** The one bit of really impressive magic Molly knows to begin with is a spell that makes her shadow detach itself and do a dance. It turns out to be useful during a confrontation with a crooked property developer, and then again at the climax.
* In ''Literature/MrStandfast'', Hannay is given a decoration to wear on his pocket watch to identify him to another British intelligence agent. They meet, look at each others' watches, and the story proceeds. Several chapters later, when Hannay is alone and in desperate straits, a complete stranger (also, it turns out, a British intelligence agent, in the area on unrelated business) notices his watch decoration and offers him assistance.

* ''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]].

** In series 6, the Teselecta robot, which is controlled by temporarily-miniaturised humans and which can impersonate anyone, has [[Recap/DoctorWhoS32E8LetsKillHitler an episode]] devoted to it. In the [[Recap/DoctorWhoS32E13TheWeddingOfRiverSong 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 [[Recap/DoctorWhoS32E1TheImpossibleAstronaut 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.]]

* 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.]]

** 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.

* ''Series/CriminalMinds'' The episode "L.D.S.K." establishes that Hotch keeps a backup gun in an ankle holster in the beginning of the episode; and [[ChekhovsGun sure enough]] this proves vital to stopping the killer at the end. The fact that he has a back up gun there would be important in sporadic episodes throughout the series, typically involving him having lost his first gun, and then grabing this one.

* Opera - Verdi's "Rigoletto" (and the Victor Hugo play "Le Roi s'amuse" on which it is based, although in the court of a French King rather than an Italian Duke): a curse that strikes twice. At the denouement of Act 1, the curse is pronounced by Count Monterone, on the court jester Rigoletto, as revenge for the latter's part in (and subsequent mockery of) having provided Monterone's daughter to the Duke of Mantua as one of his many mistresses in debauched parties. At the end of Act 2, it is Rigoletto's own daughter Gilda who is carried off by the courtiers to be the Duke's next plaything, with Rigoletto tricked into helping them. The curse having now struck, Rigoletto believes the worst has happened: and witnessing Monterone being dragged off to jail, swears that he will be the instrument of the old man's revenge on the Duke (whom he also cursed). Rigoletto engages an assassin to murder the Duke on one of his incognito amorous adventures around town: however, the assassin's sister falls in love with the Duke, they agree to substitute another target - the next random stranger to knock on the door of their inn. The whole scene has been overheard by Gilda, who decides to die for her "lover" even though he has now spurned her, and knocks on the door herself. Rigoletto, coming back for the body, discovers his daughter dying, and realises that Monterone's curse has struck for a second time. (Meanwhile, the Duke gets off scot-free, so much so that he never even so much as learns there was an assassination attempt against him, and the assassins never even learn that their intended target was the Duke...)

* ''VideoGame/MonkeyIsland'': Rule of thumb: If you're taught how to make one of something, you're gonna need at least two of it. Second rule of thumb: If an item doesn't disappear from your inventory after using it in an obvious way, you're going to have to use it later in a non-obvious way. Some examples:
** ''VideoGame/TheSecretOfMonkeyIsland'': The root beer.
** ''VideoGame/MonkeyIsland2LeChucksRevenge:'' The voodoo doll.
** ''VideoGame/TheCurseOfMonkeyIsland'': The hangover cure and the crowbar.
** ''VideoGame/EscapeFromMonkeyIsland'': The Ultimate Insult and 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), The Pyrite Parrot, [[spoiler:Guybrush's hook]] and 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]].
* ''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.
* In ''Neoquest II'', an RPG in ''{{Website/Neopets}}'', the sword you start off with is also the best sword to use against 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.

* ''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."
* ''Franchise/{{Halo}}'': In ''VideoGame/HaloCombatEvolved'', 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 in order to prevent Chief from accidentally destroying the entire galaxy. In the end of ''VideoGame/{{Halo 3}}'', [[spoiler:the Flood has taken control of the Ark, 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 are destroyed. With an almost completed ring already inside the station, the only thing needed for it to destroy the Flood would be an Index to activate it. ''"I'm a thief... but I keep what I steal."'']]
* The Sword of Gith in ''VideoGame/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.

* 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.

* The [[spoiler:birdseed]] in the third episode of ''VideoGame/WallaceAndGromitsGrandAdventures'' is used for 3 separate puzzles.
* In ''VideoGame/Uncharted2AmongThieves'', 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:PandorasBox]]
* In ''VideoGame/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 ''VideoGame/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 ''VideoGame/{{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/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.]]
* In ''VideoGame/JurassicParkTheGame'', Sorkin activates one of the tour cars for Gerry, Jess, and Nima to use when they need to get to the Visitor Centre. After a long confrontation with the ''T. rex'', Gerry then gets her to activate it again, [[LivingMotionDetector distracting the giant predator with the movement]] and luring it away. It doesn't reappear until episode four, when it turns up and takes Gerry and Nima to the marine exhibit.
* ''VideoGame/TheBizarreAdventuresOfWoodruffAndTheSchnibble'': The chewing gum, which is required twice (the second one at the end of the game).
* ''VideoGame/FinalFantasyIV'': When Cecil becomes a Paladin, he receives the Legend Sword (SNES version). You find a number of more powerful swords as you progress through the game, but if you can acquire the Adamant ore and take it to a certain blacksmith, he'll temper the sword and make it into the more powerful Excalibur.
* In ''VideoGame/{{Shantae}} and the Pirate's Curse'', the Palace Disruptor Cannon is first used to accidentally open a path into the last Den of Evil and apparently incapacitated for the rest of the game when a component needs to be replaced before it could be fired properly [[spoiler:only for it to return at the end of the game during the battle against the TrueFinalBoss when [[PirateGirl Risky]] hijacks it and uses it to help Shantae blow the Pirate Master up to kingdom come]].

* ''VideoGame/TheElderScrollsVSkyrim'' requires you to use an Elder Scroll to [[spoiler: learn the one Shout that will allow you to defeat Alduin by time-traveling back to when the Shout in question was invented]]. Once you're done with it, you can (optionally) haul it up to the College of Winterhold and sell it to [[ScaryLibrarian Urag gro-Shub]] for a nice price. Then the Dawnguard DLC comes around, and have fun trying to get your Elder Scroll back...

* In ''VideoGame/FinalFantasyVIIRemake'', when Cloud falls from the Sector 5 reactor into Aerith's church, he uses a GrapplingHookPistol in a somewhat successful attempt to arrest his fall (this also serves to explain how he survived falling from such a height, something the original game glossed over). [[spoiler:When Shinra attacks the Sector 7 support pillar, Wedge gets knocked off the tower...but then uses the same kind of grapple gun to catch himself, which keeps him from dying as per the original. Shortly thereafter, Leslie Kyle gives Avalanche several souped-up grapple guns so they can climb up to the plate and infiltrate the Shinra Building.]]

* Not to forget Tucker's Sword in ''Machinima/RedVsBlue''. First it's a sword, then it's a key. [[spoiler:And when you think they are just going to use it like a sword some more, there are two other instances of them needing to use it as a key!]]

* While Pete Abrams of ''Webcomic/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.
* ''Webcomic/TheOrderOfTheStick'':
** Belkar acquires 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.]]
** After being mocked for having Intelligence when it doesn't have a direct effect on a Fighter's combat ability, Roy shows off the perks when his knowledge of architecture (thanks to having both the stat and cross-class skill ranks) [[spoiler:to collapse a ceiling on his opponent]]. Later, that same knowledge of architecture allows him to identify [[spoiler:the fact that a pillar isn't load-bearing and thus is most likely hiding something]].
* ''Webcomic/{{Sinfest}}'': Glitter points really come in handy a lot.

* An episode of ''WesternAnimation/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.
** ''WesternAnimation/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.

* 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.
** There's also the Waterbending Scoll. Obtaining it is the source of conflict for one episode, then it can be assumed that any gains Aang and Katara make in their waterbending from then until they reach the Northern Water Tribe can be attributed to the scroll. You wouldn't expect it to serve any purpose after that, but it does show up one more time, as an offering to Wan Shi Tong when he asks for a contribution to his library.
* In an episode of ''WesternAnimation/DextersLaboratory'' 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..
* [[WesternAnimation/TheFairlyOddparents Timmy Turner]] uses his magical time-traveling scooter several times during the series. He also sometimes uses other magical items more than once. (Including some that exploded two episodes earlier like the Shrinking Robosuit, but who cares...)

* ''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.
* The third and final part of ''WesternAnimation/RegularShow'''s GrandFinale has Mordecai and Rigby use The Power, the magical keyboard from the show's first episode of the same name, to return to the final battle when they realize [[MakesSenseInContext they've been returned to the start of the show]]. [[BookEnds This episode is even called "The Power" to reflect this.]]

* ''Series/CriminalMinds'' The episode "L.D.S.K." establishes that Hotch keeps a backup gun in an ankle holster in the beginning of the episode; and [[ChekovsGun sure enough]] this proves vital to stopping the killer at the end. The fact that he has a back up gun there would be important in sporadic episodes throughout the series, typically involving him having lost his first gun, and then grabing this one.

** It might even go so far as to be Chekov's Yo-Yo. You use it, then again, then again, then ''again'', then '''''again'''''...

** Vaarsuvius learns the [[http://www.giantitp.com/comics/oots0842.html consequences]] of using [[http://www.giantitp.com/comics/oots0639.html a certain spell]].

* ''Manga/MahouSenseiNegima'' has one that crosses continuities; an antagonist attacks Negi using an attack that originated in Creator/KenAkamatsu's previous manga ''Manga/LoveHina''. There's even WordOfGod to support the idea that they take place in the same universe.

* In ''Manga/{{Naruto}}''

* 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]].

* 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.]]

* ''Manga/RaveMaster''

* ''Manga/FairyTail''

* Fanfic/AGrowingAffection:

* ''FanFic/SonOfTheDesert'': Edward snarks about Roy not knowing anything about Ishvalans after Ed manages to talk Scar down in Ishvalan without Roy knowing what they're saying. Roy later learns enough language and culture to apologize to Edward in Ishvalan. [[spoiler: In the story's climax, Roy gives Ed a traditional marriage proposal.]]

* MLP fanfic [[https://www.fimfiction.net/story/16375/sharing-the-night Sharing the Night]] makes one of Twilight's cutie mark [[spoiler: when she accidentally assumes control of the stars]]

** Marty's radiation suit in the first movie. It's used to (accidentally) disguise Marty as an alien at the Peabody farm, then it gets used (intentionally) to disguise Marty as an alien to scare George into asking Lorraine to the school dance.

** Will's sword throwing in ''[[Film/PiratesOfTheCaribbeanTheCurseOfTheBlackPearl The Curse of the Black Pearl]]'' 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.

* 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.

* In ''VideoGame/SonicAdventure2'', the Mystic Melodies seem useless after doing the lost Chao missions, but some Hard Level missions require them for advancement.

[[folder:Anime and Manga]]

[[folder:Fanfiction]]
* FanFic/AGrowingAffection:

* ''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.

[[folder:Film — Animated]]
* Famed Mexican artist Frida Kahlo in ''WesternAnimation/{{Coco}}''. She's first used as a disguise by Hector, which segues into him knowing where to take Miguel to find Ernesto de la Cruz because he borrowed the costume from a show Frida was planning with him. Miguel ends up meeting the ''real'' Frida as she prepares for the show, and she's the one to tell him where to find de la Cruz-- at a very exclusive party at his private tower. She also compliments his artistic instincts for good measure. Later on, Hector ends up getting into the party by disguising himself as Frida ''again'', and Miguel and his family ''all'' disguise themselves as Frida with her blessing to get to de la Cruz in the climax.

* ''WesternAnimation/{{Zootopia}}'' has Judy's carrot-shaped pen/recorder. It's how she blackmails Nick into helping her, [[BrickJoke which is then used by Nick to tape Judy's teary-eyed confession that she needs him.]] [[spoiler: It is finally used to tape [[BigBad Bellwether's]] confession.]]

[[folder:Film — Live-Action]]

[[folder:Mythology]]

[[folder:Webcomics]]

* In ''Webcomic/TheOrderOfTheStick'', Belkar acquires 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.]]
** After being mocked for having Intelligence when it doesn't have a direct effect on a Fighter's combat ability, he shows off the perks when his knowledge of archetecture (thanks to having both the stat and cross-class skill ranks)[[spoiler: to collapse a ceiling on his opponent]]. Later, that same knowledge of archtechture allows him to identify [[spoiler: the fact that a pillar isn't load-bearing and thus is most likely hiding something]].

* ''Webcomic/GirlGenius''

* [[ChekhovsGag An early joke]] in ''WebAnimation/{{RWBY}}'' involves each student of [[AcademyOfAdventure Beacon Academy]] being assigned rocket-propelled lockers to store their weapons and [[ButtMonkey Jaune]] getting tossed into one of them by a local bully and launched off to god knows where. In the next volume, it's shown that they can be used to quickly acquire one's weapons in case of emergency. When Ruby notices something fishy going on at a communications tower, she walks straight out of the dance party and calls her locker (which leaves a crater on the ground as it lands, by the way) with her [[SinisterScythe Crescent Rose]] inside. In volume three the lockers make a comeback during a battle, used by ''all'' of the students to get their respective weapons, as well as lockers ''themselves'' being used as weapons to strike down a giant monster bird. The same episode involves yet another use of these lockers: [[spoiler:Ruby launches one of them towards an airship and ''flies on it'' to quickly reach said ship]]. Thought Rooster Teeth ran out of ideas on how to use them? In the volume three finale we learn the ''real'' reason behind the initial ChekhovsGag: [[spoiler:It's established that a person may be stuffed into the locker and launched off to somewhere else without any real harm. Which is exacly what Pyrrha does to him to make sure that he's safe and that he won't stop her from facing [[TheHeavy Cinder]]]].
* 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.
* Not to forget Tucker's Sword in ''Machinima/RedVsBlue''. First it's a sword, then it's a key. [[spoiler:And when you think they are just going to use it like a sword some more, there are two other instances of them needing to use it as a key!]]
* When the Red Panda enlists in the army and joins the Home Team in the ''Podcast/RedPandaAdventures'', he discovers that the government has multiple secret files that contain his and the Flying Squirrel's secret identities. A running gag for a while is the Panda and Squirrel locating the copies and not only doctoring them to hide their identities, but altering each file ''differently'', with progressively more outlandish backstories, such as one claiming the Red Panda was actually his own commanding officer, Colonel Fitzroy. This initially comes back when Fitzroy is gunned down as part of an attack on the Home Team superheroes' secret identities, and the Flying Squirrel uses the fact Fitzroy was a target at all to deduce the culprit was someone with access to the Home Team file. In later episodes, Canadian government officials make reference to the Red Panda and Flying Squirrel being a reformed mobster and his moll, revealing that the government still has the doctored files and thinks them genuine.

** [[spoiler:Trucy's panties]] are used to object to testimony in the second case of ''Apollo Justice'' at least 3 times; first to show proof of [[spoiler:other crimes on the same night]], then to show [[spoiler:what the college student witness was hiding]], and then, at the very end of the case, to prove [[spoiler: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.]]

** The Sirius Island arc introduces two spells: Fairy Sphere, a defensive spell that Mavis seals Fairy Tail inside to protect them from Acnologia on Sirius Island; and Magilty Sense, Merudy's signature magic, which she reveals earlier in the final arc can multiply other people's power. Incidentally, both spells require a deep, emotional bond between others to be properly cast. [[spoiler:Lucy--one of the most empathetic characters in the series, as noted in ''Anime/FairyTailTheMoviePhoenixPriestess''--figures out that they can use Fairy Sphere to [[SealedEvilInACan seal Acnologia away]], and Merudy uses her Magilty Sense to link Lucy with every wizard on the continent to power the spell.]]
** Wendy picks up on Irene's ability to enchant other objects and people with her own magic to get out of a BodySwap and power up Erza's sword. [[spoiler:When faced with Acnologia's disembodied soul, Wendy uses this technique to [[AllYourPowersCombined transfer her and the other Dragon Slayers' magic into Natsu]], which proves to be [[PhlebotinumOverload more magic than Acnologia can handle]] when Natsu slams all of it into him at once while he's paralyzed by Fairy Sphere's activation.]]

** The final part of ''Anime/FairyTailDragonCry'' introduces the Quartum Army, which are {{Artificial Human}}s created from Dragon Lacrima as "Fourth Generation" Dragon Slayers. They are briefly referenced in ''Manga/FairyTail100YearsQuest'' in order to set up the introduction of the "''Fifth'' Generation" Dragon Slayers.

* Shortly after the end of her [[DayInTheLimelight arc]] we find out that Erza, who we saw in an earlier chapter of ''Manga/FairyTail'' losing 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 FinalBattle in ''Manga/FairyTail'' is ultimately won through the reuse of one-off techniques:

** Wendy picks up on Irene's ability to enchant other objects and people with her own magic to get out of a BodySwap and power up Erza's sword. [[spoiler:When faced with Acnologia's disembodied soul, Wendy uses this technique to [[AllYourPowersCombined transfer her and the other Dragon Slayers' magic into Natsu]], which proves to be [[PhlebotinumOverload more magic than Acnologia can handle]] when Natsu slams all of it into him at once.]]

* ''Franchise/KamenRider'': ''Series/KamenRiderBlade'' threw a boomerang in 2005 and it didn't come back around until '''twelve years later''' in an entirely different series: Near the end of ''Blade'' it's revealed that [[spoiler:if the Joker is the last Undead standing, [[TheEndOfTheWorldAsWeKnowIt the world will end]]; [[TheHero Kazuma Kenzaki]] manages to avert this by turning himself into a second Joker, putting the Battle Royale into a perpetual stalemate]]. Then in 2017 in the ''Series/KamenRiderExAid'' spin-off ''Kamen Sentai Gorider'', [[spoiler:Kuroto Dan enacts an elaborate plan to bring himself back to life, including an UnwinnableByDesign virtual world with himself disguised as Kenzaki appearance -- complete with his powers -- to oversee things. This attracts the real Kenzaki to the game world, who reveals that Dan screwed himself: since he's the ''only'' Undead around, the (game) world ends...and Dan's plot along with it.]]

* In the very first [[Roleplay/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.

* ''Disney/{{Zootopia}}'' has Judy's carrot-shaped pen/recorder. It's how she blackmails Nick into helping her, [[BrickJoke which is then used by Nick to tape Judy's teary-eyed confession that she needs him.]] [[spoiler: It is finally used to tape [[BigBad Bellwether's]] confession.]]

* The FinalBattle in ''Manga/FairyTail'' is ultimately won through the use of one-off techniques:

** In volume 6, when Haru is facing down Siegfried, he's briefly able to get past his magical defenses by using the Eisenmeteor form of his sword, having realized that magical defenses only work on magic infused items. Much later, Siegfried is facing down Haja the Infinite, who has unlimited magic power. Unable to beat Haja with sheer magic strength, he instead rams him through the heart with a staff devoid of magic, having remembered what Haru said and realizing that Haja would be unable to block it.

** Wendy picks up the ability to enchant other objects and people with her own magic during the battle with Irene to get out of a BodySwap and power up Erza's sword. [[spoiler:When faced with Acnologia's disembodied soul, Wendy uses this technique to [[AllYourPowersCombined transfer her and the other Dragon Slayers' magic into Natsu]], which proves to be [[PhlebotinumOverload more magic than Acnologia can handle]] when Natsu slams all of it into him at once.]]