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It Only Works Once

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Flash: [to J'onn] What's the big problem? Can't you just whip up another batch of that nerve gas?
J'onn: Unfortunately, no. The gas can only be made from a rare Martian plant. I brought a sample with me, but it was destroyed when I was captured.
Flash: Uh, what's Plan B?

...and if it fails, too bad. You only get the one shot.

It Only Works Once is a trick or technique which is completely useless in the following episodes. It could be something where you literally have only one shot, like a Forgotten Superweapon or other Applied Phlebotinum that cannot be replaced once it's used up. It might be a tactic that relies on the element of surprise, like an attempt to exploit an Achilles' Heel vulnerability that the enemy will correct or at least guard more carefully once it's brought to his attention.

Reversed, it is a common trope of cartoon series. The Big Bad will come up with some undefeatable plan that almost works save for some streak of luck on the part of the heroes (see the Road Runner shorts for some especially lucky breaks), but will never think of trying it again after being foiled the first time.

Occasionally a special attack that Only Works Once will end up being used in The Worf Barrage.

When you're getting near the end of a show or film and you know the trope will be averted because it's near the end and not a tragedy work, you're being Spoiled by the Format.

Never Recycle Your Schemes is a subtrope. Compare So Last Season, Forgotten Phlebotinum, Holding Back the Phlebotinum, No Plans, No Prototype, No Backup, and Won't Get Fooled Again. Contrast Uniqueness Rule for when a game only allows you to use a mechanic once per battle. See also Adaptive Ability, Reed Richards Is Useless, and the Disposable Superhero Maker. Most Wave Motion Guns apply a limited form of this trope by making its use prohibitively slow and energy-intensive, but the usual dramatic application is rather different. Often overlaps with Death or Glory Attack. See also Limited-Use Magical Device, which involves a magical object or magic spells that can only be used a limited amount of times, often just once.


Examples

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    Anime & Manga 
  • Assassination Classroom:
    • Irina's biggest flaw as an assassin is that once her Honey Trap cover gets blown, she gets flustered and can't complete her job. In one chapter, her attempt to seduce Karasuma into lowering his guard so she could mock stab him doesn't work for a second because he knows that's how she operates as an assassin.
    • Akari Yukimura was able to mask her true identity and feelings as "Kayano" for almost the entire series, but after she threw off the act once, doing so became much harder.
  • In the final episode of The Big O Roger Smith finally puts some of the pieces of the Myth Arc together and unlocks the Wave-Motion Gun built into his mecha just in time to put an end to the Big Bad. Wouldn't you know: He missed, and firing the one shot burns the gun to a crisp.
  • Bleach:
    • The Kido Cannon in Bleach: Memories of Nobody burns itself to ash after being fired only once.
    • The series has shown a couple of examples where a character can enter a Super Mode at the cost of losing all of their powers when it wears off. Naturally, it also provides ways to regain their powers.
    • There's also Muramasa, main antagonist of the anime filler Zanpakutō Rebellion arc. Muramasa is a Zanpakutō spirit whose power is bringing other Zanpakutō spirits to life and turning them against their masters. He does this by tapping into their most suppressed instinct and using it to control them. The only clear way to break the spell is to defeat the Zanpakutō spirit, but if that happens, Muramasa's power won't be able to affect it a second time.
    • This is what makes defeating Askin so difficult. Because he has the power to control his and others' resistance to anything he's experienced and absorbed once before, if it didn't kill him the first time (and he's really hard to kill), it won't affect him at all the second.
  • Lelouch's mind control power in Code Geass can force people to obey any command Lelouch gives them ... but only one command per person. After it's been used on someone once, it won't work on the same individual again. Eventually, Lelouch gets around this by issuing the command "obey all my commands".
  • Digimon:
    • The GeoGrey Sword in Digimon Data Squad; after its first appearance, it ceases to work on anyone, up to and including the villain in The Movie.
    • In Digimon Fusion there's the digimemories which have the data of legendary Digimon, and can summon them to use their abilities. But they can only be used once for each zone.
  • Dragon Ball:
    • The Mafuba/Evil Containment Wave was able to seal King Piccolo away in a rice cooker in his backstory, but fails all three times it's used on him or his son/reincarnation:
      • Roshi tries to use it on King Piccolo, but it fails simply because he missed the jar.
      • Tien also planned to use it against King Piccolo, but in the manga practicing the technique broke the jar before he could even try. In the anime he gets a chance to try it, but Drum jumps in front of the wave himself and King Piccolo destroys the jar before Tien can even seal him.
      • Kami tries to use it on Piccolo (so he can stop him without killing him and thus himself), but Piccolo just turns it on him, mentally gloating, "If you thought this incarnation would be beaten like the last, then you have not thought!"
    • In Dragon Ball Super, Trunks and Mai attempt to use the Mafuba on Zamasu, unable to beat the immortal god by himself or with Goku and Vegeta's power. However, because they forgot the seals to prevent escape, Zamasu's able to escape and flips the hell out.
    • Likewise, it's revealed at the beginning of Dragon Ball Z that Shenron, and the Earth's Dragon Balls by extension, cannot grant the same wish twice; for example, if a person who has been already been resurrected is killed again, the person in question will be Killed Off for Real. Porunga, and the Namekian Dragon Balls by extension, have no such limitation.
    • Gohan fires a blast at Dabura from underwater as a distraction so he can close in and hit him. It works the first time, but when he tries it again later in the same fight, Dabura turns around and blasts him as he approaches.
  • Fairy Tail:
    • Averted with the Iced Shell spell, which works in the flashback with Gray's teacher Ur sacrificing herself to seal away and eventually kill the demon Deloria. Every subsequent attempt to use Iced Shell in the present fails not because it wouldn't work, but because Natsu is there to stop Gray from trying to throw away his life needlessly when they can beat the enemy the old-fashioned way without dying.
    • Natsu disorients Cobra by screaming really loud to overload his sensitive ears. During a rematch, Natsu tries this again, but Cobra reveals that he's learned how to absorb sound waves to power his own sonic attack.
    • Natsu states his secret weapon against Zeref is this. Because it's the last of Igneel's power, he has no way to regenerate more of it once it's used up. He can still unleash a facsimile in "Fire Dragon King" mode, but it's not as potent as Igneel's power was.
    • In Fairy Tail: 100 Years Quest, Erza states that the weakness of hypnotism-based magic is that once a person knows how the specific spell works on the target, they can counter further usages of it, going so far as to call said weakness "understanding." She proves it by No Selling Kyria's "cutting mentality" spell in their rematch after being subjected to and recovering from its effects from their first fight.
  • Much like the Real Life example below, The Familiar of Zero pulls this with the Wand of Destruction. Only Saito can use it, and it only works once. It's really an M72 LAW rocket launcher and it has one shot, so when Longueville aka Fouquet tries to use it on Saito, it doesn't work.
  • Human transmutation in Fullmetal Alchemist. That's because you have to give up your ability to use alchemy to do it, plus the person who you're bringing back has to be trapped at the gate (and thus not actually dead), and your souls have to be linked so that you can return through their gate once you've given up your own.
  • In Gundam Build Fighters, the Star Build Strike's Absorb Shield wasn't designed this way, but that tends to be how it works out in practice. As the name implies, the shield opens up and absorbs any beam attacks that come its way, then uses the energy to power some rather impressive Limit Breaks; after its spectacular first use, most of the smarter fighters (and this being the World Championship, that meant most of them) realize what's going on and go out of their way to disable the shield first or attack with solid projectiles like missiles that can't be absorbed.
  • Inuyasha:
    • Practically speaking, Miroku's Wind Tunnel. It should be able to instakill every enemy the troupe comes across due to its ability to suck everything into the pocket dimension in his hand, but it takes Naraku one encounter to learn how to neutralize it... which makes sense, considering he's the one who put it there in the first place.
    • Later, Sesshomaru discovers the hard way that the Tenseiga can only bring a single person Back from the Dead once. In the sequel series, Yashahime: Princess Half-Demon, this is also brought up by Totosai to the recently revived Setsuna in the first episode of the second season, telling her not to die again after being initially cut down by Kirinmaru at the end of Season 1.
  • JoJo's Bizarre Adventure:
    • Part 1:
      • Subverted where Jonathan is caught off guard by Dio's attack, as the first time it was used, he was plummeting off a cliff and didn't see it firsthand. The second time it is used, he has no idea it was coming.
      • Dio's attack ended up being fatal to Jonathan in his first real encounter with it, but the story of the attack was passed down through Erina to Joseph, her and Jonathan's grandson. As a result, it never succeeds from the start on Joseph because he already knew how the move worked.
    • Straits/Straizo in Part 2 had the powerful Space Ripper Stingy Eye, an ability he witnessed in Part 1 where a vampire can shoot fluids from the eyes at a ridiculously high velocity, allowing it to cut through flesh. The first time he fires, he misses a fatal shot at Joseph, but nicks his neck. The next time he tries it, he hits a mirror reflection of Joseph, and then the third time, it is completely reflected. Joseph lampshades that he only needed to see the attack once to know how to counter it, due to the predictability that Straits would go for the fatal shots in the neck and forehead again.
    • Part 3's Anubis inverts this trope. Along with its unique traits, its skill in swordsmanship is so extreme that using the same attack twice against it is completely ineffective.
    • Later on in Part 7, during the climax of the D4C arc, Gyro uses the Super Spin Technique to attack Valentine. This attack rapidly ages cells to the point of death. Though technically successful, an imperfection in the steel ball cancels the perfect rotation, allowing Valentine to survive the attack (albeit aged up to an old man). Gyro doesn't get another shot before he's killed. Johnny later attempts the same feat, but Valentine's warning prevents the Diego Brando from another world from suffering the same fate.
  • Kinnikuman: During the main character's fight against Atlantis of the Seven Devil Choujin, the ghosts of the previously killed Devil Choujin interfere, forcing the Justice Choujin to use a magic glass to become spirits and stop the interference. When Sunshine and Ashuraman use a similar trick during their match against the Machine Guns during the Dream Tag Tournament, the other Justice Choujin try to use the glass again, only to be rebuffed by the Mountain, who knew they were coming.
  • In Kuroko's Basketball, this is the critical drawback of Misdirection Overflow. After its effect wears off, not only will that technique not work anymore on the team it was used on, but that team will also become immune to the most basic of misdirection techniques. It's described in-universe as "performing a trick while simultaneously showing how it's done."
  • The Book of Darkness in Magical Girl Lyrical Nanoha A's can only drain the linker cores of individual mages and creatures a single time, which forces the Wolkenritter to have to constantly seek out new targets. This is justified when it's revealed that the book's function pre-corruption was to act as a Magitek encyclopedia for spells. Repeat entries would just be a waste of space.
  • In the original Mobile Suit Gundam, Zeon had developed the Solar Ray Kill Sat weapon; it was basically a gigantic laser built out of a space colony. However, Ghiren Zabi got greedy with it and "test fired" it at his own father and his fleet while he was off trying to negotiate peace, burning the weapon out. This is averted in the novel trilogy, where it was fully operational and used indiscriminately.
  • In Mobile Suit Gundam SEED Destiny, ZAFT developed a weapon called the Neutron Stampeder, which triggers nuclear reactions within anything with nuclear reactors. They use it to stop a surprise attack by the Earth Alliance on the PLANT, destroying the missiles, the suits carrying the missiles and the battleships holding spare missiles, but burning out the device, which was mounted on a Nazca-class ship. Thankfully, the Earth Alliance wasn't smart enough to have spares or try the plan again in the future.
  • Naruto:
    • Izanagi, one of the Sharingan's powers lets the user cast an illusion upon himself making reality a dream and thus letting them escape life-threatening situations. However, the eye shuts permanently after it is used once. The same apply to the techniques counterpart, Izanami, that locks the victim in an endless loop.
    • Deidara's "ultimate art" C0 involves using himself as a bomb. Too bad for him, Sasuke had just made in advance an ultimate escape plan for such an occasion.
  • Negi's Pactio in Negima! Magister Negi Magi allowed use of all his partner's abilities and Asuna's antimagic (to an extent) but was merely used as a tool to keep Rakan from using his own Pactio. And after that, it was canceled. Obviously for the sake of drama (such a game breaker power) but seriously, you would think something useful like that would be kept around. Although he could easily regain it by making a Pactio with someone else.
  • One Piece:
    • Numerous villains seem to just give up after an ass-kicking by Luffy and co. despite the fact that they could logically resume their activities after the Straw Hats have left the area, especially since Luffy and company nearly never actually kill the Big Bad. Most of the time, they go a ways to justify why the Big Bad doesn't do this, but occasionally they don't bother.
    • First example: Captain Kuro. He had planned to leave a life of piracy by instilling himself as a butler of a rich child. After a few years, he was going to have his hypnotist Jango force her to write Kuro into her will, then kill her and take her money. Instead, he gets beat up and forced back out to sea. Though he couldn't have pulled this trick again on the same island (and would need to adjust the plan for a lack of a hypnotist), no one else knew he was alive and he could have tried elsewhere, yet he's still a pirate as far as we know. Later, it's revealed that the Marines learned that Kuro had faked his death; this is likely because Jango had joined the Navy after Kuro's defeat, but it's never made clear.
    • Next is Buggy, who had taken over a town. Luffy beats him and sends him flying. He could always just stay the course. However, Buggy being Buggy, he holds a grudge and starts following Luffy instead. This also happened to Alvida, who joined Buggy.
    • Crocodile looks this way since his loss of Warlord of the Sea status means he can no longer operate out in the open without drawing attention from the Marines, but his criminal organization still exists. A mini-arc revealed that after Luffy defeated him, Crocodile lost interest in the outside world, which is why he doesn't bother escaping jail with most of the rest of his Officer Agents. However, when he heard about the impending war with Whitebeard and the World Government and Luffy showed up on Level 6 attempting to rescue his brother, he offered his power to help them escape, his interest rekindled by a chance to strike back at the pirate who ruined his dreams of becoming King. And with that pirate's death, he's ready to give it another shot; the next time Crocodile is seen after that arc, he has plans to head towards the New World again.
    • On the topic of the Alabasta arc, there's Nami's Clima-Tact; due to miscommunication, Usopp had made it little more than a tool for parlor tricks, but the Tornado Tempo was specifically described as an attack that can work only once. This is due to the attack relying on wound springs inside one of the 3 poles. Once it fires, it looks like it would take significant effort to reload (think trying to re-coil a stretched out slinky) and many of Nami's attacks require all 3 poles, so losing one means her fight is basically over regardless of if she's won or not.
      Usopp's Instructions: Tornado Tempo packs a knockout punch. However, it is absolutely a weapon of last resort! You have only one shot! If you miss, it's all over.
    • Brook's Devil Fruit grants him the ability to come Back from the Dead... once. Since his soul took too long to find his body, he is now a living, still killable skeleton. After two years of training, however, he has subverted the trope by expanding on his power, making its ability to revive him only one aspect of his powers.
    • Devil Fruits in general are an unusual example of this trope. Firstly, only one person can have the power of a given Devil Fruit at a time; if the fruit is divided into pieces and given to multiple people, the first person to bite one gets the power. Secondly, a person can only have one Devil Fruit's power in their life; if they attempt to eat a second, it triggers a violent reaction that kills them. Blackbeard being able to acquire the power of a second Devil Fruit is specifically called out as an unprecedented turn of events, and how he achieved that is one of the great mysteries of the series.
  • Pokémon: The Series:
    • Any Pokémon with the move Overheat, though most notably Ash's Torkoal, could only use it once at full power. This has its roots in the games, where, while the move can be used multiple times, it cuts the Special Attack by half whenever it is used.
    • Ash's Snivy's Attract only works once for an opponent. After that, they find a way to break through it.
    • During Ash's battle with Whitney in A Goldenrod Opportunity, Whitney is able to win by having her Miltank use Rollout constantly to beat Cyndaquil, Totodile and Pikachu. During the rematch, Whitney has her Miltank use Rollout constantly again, but Ash, inspired by taking down Team Rocket's barrel-bot, has Cyndaquil wear down Miltank, Totodile use Water Gun to dig trenches and finishes the battle by having Pikachu use Agility to race to one of the trenches and hide so when Miltank passes over him, Pikachu leaps up and slams Miltank into the air allowing Pikachu to fry the Milk Cow Pokémon.
    • During Ash's third battle against Paul in the Sinnoh League, Paul is revealed to have copied Ash's Counter Shield. While Gastrodon uses it to great effect against Staraptor using Muddy Water, when Electivire tries it with Thunder, Infernape digs under the Counter Shield and strikes the Electric-type from below.
  • Ranma ½:
    • In a similar instance to the Saint Seiya example above, an OVA pitted (female) Ranma and Akane versus two powerful sisters (never happened in the manga). After getting creamed in their first match, the two leads train for a rematch. The sisters' ordinary attacks then prove ineffective against Akane (who has trained up to their level) and their special skills are useless against Ranma (who explicitly says, "Your wind attack ain't gonna get me twice! I've seen it once and it's easier to avoid it!")
    • Turning the trope on the villain's favor, the manga confronted Ranma with the Musk Prince Herb, descendant of a dragon and master of chi techniques. When Ranma tried to use the overwhelmingly powerful Hiryu Shoten Ha technique on him, Herb recognized it and easily dodged it, since he had seen it many times before in the past and it was arguably part of his education. This is later turned around on Herb when Ranma tries the technique again, mocking her that it won’t work since he’s dodged and countered it before. Ranma counters that Herb’s dodge move won’t work this time as she had upgraded the technique within the battle into the Hiryu Korin Dan. This was the same problem with Happōsai, who had once been on the receiving end of this technique (from a young Cologne) and already knew how to thwart it.
    • Even further: when Ranma used the Parlay du Fois Gras technique on Picolet Chardin, it only worked for a few instants; both he and his teacher recognized the technique and immediately used a variety of defenses. Although Ranma tried to use new variations to get around these counters, each only worked once, until she was left with no way to attack her opponent.
    • Shampoo once offered Ranma a packet of bath powder that would nullify his curse in exchange for a date. She learns soon after that the powder works only once, but leaves that part out when Ranma finally gets the powder.
  • REDLINE: The president of Roboworld uses the Three-Point Disintegration Cannon to try to kill Funky Boy. Unfortunately, Funky Boy regenerates, while the Cannon needs two hours to recharge.
  • The Gold Saints in Saint Seiya take pride in repeating how an opponent can only use a technique against them once, and then becomes ineffective. Their reasoning is that, having seen the attack once, they've learned how to avoid it. Sometimes the Bronze Saints are allowed to repeat this phrase, but only if their enemy poses no real threat whatsoever.
    • Only problem is that Seiya insists in using the same technique over and over, initially not hitting his enemy, but eventually it does and he didn't change his technique, he's just doing it faster.
    • Only SAINTS OF ATHENA have such a power or technique, as they learn to do it with their training. Seiya's case is always lampshaded as meteors being so numerous they turn into one big attack. Still, the dialogue fails to convey this realistically or seriously.
  • A Simple Survey:
    • One short film focuses on "time lodes", a method of limited time travel which allows the user to make a single, limited change in the past. Once a change is made, that point in time is locked down and can no longer be changed whether it worked as intended or not.
    • When a truly absurd event occurs, Alice will be summoned. However, because the event has occurred in reality it is no longer absurd. As such, the notion of "absurd" and Alice herself will evolve to become an even more absurd existence.
  • Space Adventure Cobra: Cobra's arch enemy of the Three Sister's Arc, Crystal Boy, is Nigh-Invulnerable to just about every attack Cobra used against him. Near the end of the Arc Cobra faces off against him and after a long fight he catches him off guard by launching his fake arm at him via the Psychogun, presumably killing him. When he appears in the Psychogun OVA Cobra attempts to kill him the exact same way only to have him catch the fist mid air and proclaim that the same trick wasn't going to work twice.
  • In the first episode of the series, a hectic encounter with hostile aliens forces Space☆Dandy to reveal a decoration on the Aloha Oe that is actually an explosive powerful enough to an destroy an entire planet. If he had thought it through, he would've realized that detonating it spells doom for everybody, including himself and his crew.
    Dandy: I knew there was a reason I hadn't used this trick before.
  • Summer Time Rendering: Once Haine starts retaining her memories of the previous time loops, not a single plan attempted by the heroes works a second time.
    • Shinpei, Hizuru, and Nezu raid Shadow Shiori's house like they did in the previous loop, this time to have Shadow Ushio erase her once and for all. Unlike last time, Haine knows they're coming and has Shide lie in wait for them, aiming to capture Shinpei alive to prevent him from looping. Hizuru and Nezu end up dead, forcing Shadow Ushio to decapitate Shinpei which activates his looping power in the nick of time.
    • During the battle at Torajima, Hizuru peels Shide's armor off by having Ryuunosuke invade his body, but the fight and its conclusion are erased from reality thanks to Shinpei activating the loop elsewhere on the island. Only Haine and Shide retain their memories of the fight, so when Shinpei and Ryuunosuke come up with and attempt the same tactic in the final battle, Shide already has the know-how to counter their trick.
  • The Bartolls of the Super Robot Wars: Original Generation OVA series worked on this trope — should an attack kill one of them, they would instantly adapt to it and find ways to dodge it or create ways to protect themselves. By the end of the second episode, Cybuster's forced to use CyFlash and the SRX is forced to use the Hyper Tromium Cannon just to wipe out a small army of them.
  • Tengen Toppa Gurren Lagann. During their first encounter, Viral makes a point of telling Kamina sneak attacks only work once. He's later proven wrong. By the Lagann Impact, no less.
  • The Gravity Cannon, from Zoids: Chaotic Century, only had three shots available, one of which had to be a test-fire. It didn't work. A fourth shell is later created, it still doesn't work.

    Comic Books 
  • Astro City: The "Dark Ages" story arc featured the Innocent Gun, a powerful mystic superweapon that was left behind by alien Precursors to be used to protect humanity from a vaguely unspecified future threat, and was crafted so that it could only be used once. Unfortunately, The Lancer ended up using it against another Big Bad, tearing a hole in reality and leaving the gun unavailable for future use.
  • The Avengers: Marvel villain Ultron tends to come back whenever he's destroyed, now with immunity to whatever wrecked him the last time.
  • Batman: The Calculator had an ability he'd use after each of his losses to a hero to "turn defeat into victory". He'd hit a button on his costume, which would render him immune to the powers of the hero who had just beaten him. Unfortunately, the DCU has an inexhaustible supply of heroes, so it never did him much good.
  • Diabolik: The reason why Diabolik and inspector Ginko don't bother reusing plans and gadgets: the next time the police will have figured out how to counter Diabolik's tricks, and Diabolik will know how to get around the counter, as shown by Diabolik's perfect masks (one of the rare tricks he does reuse: the police checks faces multiple times if they even suspect he's around, and sometimes Diabolik can pass through the checks if the circumstances are right). However this is valid only if the opponent knows what happened, as otherwise they can't figure a way out of it.
  • Doctor Strange: Doctor Strange once was turned into a vampire by Dracula, who boasted that since Dracula rules over all vampires, Strange was unable to attack him. Indeed, try as he might, Strange could no longer call upon his usual sources for spells: Aggamotto, Cyttorak, Watoomb, etc. In desperation, and with effort that nearly killed him, Strange called out the name of God.
  • Fantastic Four:
    • Many of Reed Richards' attempts to cure The Thing have been of the only-works-once variety. These always come with a reversal method which Ben will inevitably use, sacrificing his humanity to stop the villain.
    • When Kristoff Vernard was uploaded with Doctor Doom's memories to take his place after his apparent death, he decided to attack the FF by reusing an old plan to send the Baxter Building into orbit, reasoning that it had only failed the first time the true Doom attempted it because of the treachery of Namor; the plan failed again, but only because Kristoff's uploaded memories didn't include the Invisible Girl's ability to generate forcefields, allowing the FF to survive the building exploding in space and return to Earth.
  • Green Lantern: The villain Traitor was originally a warrior named Devos Ungol who was fitted with a high-tech suit of armour that drew power from the energy of dying stars. What made Traitor particularly dangerous was that even if an opponent was able to damage his armor, such an attack would only be effective once, as his armor adapts to ensure that any successful attack won't work again. After Traitor defeated Abin Sur's predecessor as a Green Lantern over a century ago, he was initially trapped on Earth in a weakened condition as the close proximity of the sun prevented him from gaining more power, but after he escaped during Final Night he was swiftly restored to full power, forcing Kyle Rayner to hit him with an internal EMP and then bury him at the core of a dead planet so that he couldn't "reboot" from that attack.
  • The Incredible Hulk: A 2003 storyline in Hulk (1999) focused on Bruce Banner learning that he was suffering from Amyotrophic lateral sclerosis, which would leave him forced to remain the Hulk once his body became so badly afflicted by the disease that he couldn't continue as Banner, until he eventually received a cure from the Leader. However, this cure was only possible with gene sequences taken from the corpse of Brian Banner (Bruce's long-dead father) and inserted into the Hulk's genetic structure by Scott Lang under the direction of Reed Richards, these new genes being integrated into Banner's physiology during the energy surge when the Hulk returned to Banner, making it clear that this cure would only work for Banner
  • Legion of Super-Heroes: In one of the try-out issues, one of the would-be Legionnaires was a woman called X-Bomb Betty, who had the power to "create an explosion of 150 million megatons". When they asked her to demonstrate this she got a panicked look and said, "But ... but I can only do it once!"
  • Martian Manhunter: The Martian Manhunter once beat Despero with his innate Martian power to make someone believe that they're experiencing their most fervent desire. He'd never mentioned this power before and would never use it again, because, he explained, using it was so stressful that any one Martian could only do it once in their life. (Focusing on the pathos of his decision to use a power that his culture considered the ultimate gift to give a loved one to defeat a rampaging villain helped gloss over the Ass Pull.)
  • Paperinik New Adventures: In issue #14, a shadow creature can only be destroyed by a weapon created specifically for the job; the heroes, however, didn't have enough time to manufacture more than two charges for the weapon. As Paperinik puts it: "Be careful where you aim, you won't get a third shot."
  • Runaways: This trope is used as an actual story element, as Nico Minoru's weapon, the Staff of One, can cast any spell whatsoever but then can never cast it again. (Attempting to repeat a spell results in random effects.) It essentially serves as a leash to her otherwise godlike powers. However, it turns out that she can only use each specific spell with a specific code word once; in a team-up with the Young Avengers, she was able to cast the same spell repeatedly by running through The Vision's language banks, while on another occasion she was able to 'reuse' a 'Freeze' spell by instructing her enemies to freeze at a specific temperature.
  • Shazam!: The original 40s Captain Marvel once fought a character that could cast any spell — once. He also had one, and only one, weakness. Their fights consisted of the two of them flipping through notebooks that listed everything they had tried so far, trying to come up with strategies.
  • Spider-Man:
    • This ended up happening by the eighth or so issue of The Amazing Spider-Man (Lee & Ditko). In the Vulture's first appearance, Spider-Man took him down by simply clipping his wings with a device designed to cancel out the magnetic harness that allowed him to fly. Not so in their second encounter, where the Vulture puts in a fail-safe to get around this, and sucker-punches Spidey the minute he isn't looking.
    • Similarly, after being blinded with a squirt of webbing, Doc Ock started treating his glasses with a non-stick coating.
    • Spidey once came across Stilt-Man wreaking havoc. He was disappointed, as the villain had designed a mask to keep Daredevil from hitting him in the face with his stick. Spidey just webs him to a lamppost.
    • In an old Marvel Team-Up issue, Black Panther concocted a super strong web fluid to hold Stegron, a villain that had previously broken out of Spider-Man's webs. It was stated that the new serum was very unstable, and Black Panther himself warned Spider-Man that it could only be used on this one occasion.
    • Hooky has him meet an immortal young woman pursued by a hideous monster she calls a thunder roach, who has the power of only getting hit by any spell once, after which it won't work again.
    • The Night Gwen Stacy Died is a meta example. It was a powerful story that provoked lasting character development in Peter and Mary Jane, plus dealing with the problem of Peter becoming less relatable if his relationship with Gwen progressed too far (and getting rid of a rather boring character). Problem is, it can't happen again; the shock value would be gone, Peter's relationship with Mary Jane was now locked in, and killing off her would run the risk of Peter becoming too much of a Failure Hero to continue as Spider-Man.
  • Superman:
    • Doomsday has "evolution" powers, such that he could adapt to counter attacks once used against him — i.e., having once been beaten by a Green Lantern's ring, he became relatively immune to its power. In Superman/Doomsday: Hunter/Prey, the Radiant's energy attack which killed Doomsday in the past no longer has any effect on the creature when the recreated Radiant tries it again on him.
    • The Death of Superman: Superman's revival after his death at the hands of Doomsday is considered unique because of the circumstances behind it, involving a certain revitalization chamber and, possibly, Jonathan Kent having a near-death experience with him.
    • In The Girl with the X-Ray Mind, the Phantom Zone criminals get their hands on a ray gun powerful enough to kill a Kryptonian, but they want to be certain what it works before using it on Superman or Supergirl. So they test it on their partner-in-crime Lesla-Lar, and after verifying it does work just fine, they realize the weapon was too damaged to be used more than once, and it is now useless.
    • Jimmy Olsen once discovered Superman's secret identity. At the end of the story, Superman used a combination of heat- and microscopic-visions, focused through a space jewel and directed through Jimmy's eyes, to burn out the portion of Jimmy's brain which held that piece of information. Superman lampshaded the trope by telling Jimmy that he could only perform this trick once: if he ever tried it again, he'd short-circuit his vision powers.
    • When Superboy was dying after a particularly strenuous fight, Robin was able to find a cure in one of Lex Luthor's secret labs. However the cure could only be used once and any attempt to use the same concoction again after having used it once would kill Conner.
    • In The Last Days of Superman, Supergirl uses a piece of Red Kryptonite, which restores a Kryptonian's powers on planets with a red sun (found by Superboy in Superboy (1949) #81), to keep her powers when she time-travels to pre-destruction Krypton. As all fragments of Red Kryptonite, though, it only has effect on each Kryptonian once; so neither Kara nor Kal were able to use it again.
  • Transmetropolitan: This becomes a long set up Brick Joke. Spider cloaks himself in source gas (a substance that records sounds like a microphone because reasons) before his first interview with the Smiler in order to catch his campaign in a lie. The second time he goes in, The Smiler's wise to the trick, and disables ALL of Spider's recording equipment. At the end of the comic, Spider pulls the trick a third time, and this time it works, because Spider's "been showy" with guns, and the Smiler only had him searched for weapons.
    Spider: The first trick I ever pulled on you, Callahan. Source Gas. I'm soaked in it.
  • Ultimate Marvel:
    • Ultimate Human included Tony Stark curing Bruce Banner of the Hulk. The catch was that if the Hulk returned even once, its physiology could adapt and the cure would never work again. Predictably, by the end of the comic they are placed in a situation that requires the return of the Hulk.
    • All-New Ultimates: There's a giant in town, but Kitty can not repeat the trick she used against Galactus. She needed help from SHIELD to be turned into a giant, and there's no SHIELD anymore.
  • Über: The series is an Alternate History story in which the Nazis developed super-powered soldiers, followed by the Allies, resulting in a superhuman arms race. Because the kinks of the process are still being worked out, and soldiers are constantly developing and refining new uses for their powers, there are many points in the book where a novel tactic is used to great effect. However, both sides are constantly searching for an advantage, and generally a counter-measure will be developed shortly thereafter. This is actually cited by the head of the project as a major strategic truth: if you possess a technical advantage over your enemies, you can only use it with full effect a single time, as the enemy with inevitably adapt to any future uses.
    • One notable example: the Allies, in secret, develop soldiers with Super-Speed. They're deployed before the Nazis even know they exist, and achieve great success, killing one of the most powerful superhumans in the war, though all five speedsters are also killed in the battle. However, the next time they're deployed, the Nazis have studied the battle and developed a countermeasure, which they use to devastating effect.
  • X-Men:
    • In an issue of Uncanny X-Men Rogue absorbed Nightcrawler's powers and defeated Nimrod, the mutant-killing robot from the future, by teleporting a chunk of his body away. The next time the X-Men fought Nimrod, Nightcrawler simply tried the same trick again, only to discover that Nimrod had adapted himself so that not only did it not work but the attempt messed Nightcrawler up quite badly.
    • Similarly, Sentinel robots in general had the ability to learn from experience (and transmit this information to other Sentinels), so a trick used on a Sentinel wouldn't work again on any Sentinel. Their ability to physically adapt to is more limited than Nimrod, so anything that beats a Sentinel through brute force will usually still work.
      • In Marvel's Heroes Reborn arc Doctor Doom had guard robots that had this programmed into them.
    • In the miniseries X-Men: Worst X-Man Ever, the titular character had the power to explode ... once.
  • Wonder Woman Vol. 2: During their fight against the Sangtee Empire the rebels use the trick of leaving one of their ships floating disabled with breaches in the hull near a shipping lane, with the crew inside playing dead in spacesuits to take advantage of the empire's salvaging practices in order to get the jump on them. The next time the empire sees a damaged and disabled rebel ship they instead destroy it from afar. The rebels were using the ship as a different kind of trap this time and were able to hack the empire's ships after the destruction of the abandoned ship alerted them to their whereabouts.

    Fan Works 
  • Discussed in "Always a Ranger", an AU of the confrontation with Thrax where he attacked the SPD B-Squad rather than the Operation Overdrive team. After Thrax depowers the current SPD Rangers (minus the Omega Ranger, who was dealing with another situation at the time), the Sentinel Knight cannot repair the Morphing Grid to restore SPD's powers, but he is able to reach back through time and draw five past Rangers into the present while restoring their abilities as a substitute team. When Thrax is asked why he can't just depower these Rangers as well, Thrax acknowledges that he could do that, but since the Sentinel Knight would just repeat what he's just done and draw a new team of past Rangers in as a substitute group, there wouldn't be any point to that approach, so it's best that they focus on finding a way to stop the Sentinel Knight before worrying about depowering the Rangers again.
  • Downplayed in Amazing Fantasy. Izuku can only use his Venom Strike once a day, limiting him to one usage of it in any given fight, but he'll be able to use it again after a full night's rest.
  • The Arithmancer: During Umbridge's tenure at Hogwarts, whenever Hermione does something that Umbridge doesn't want but which is still permitted by the rules Umbridge creates a new rule specifically prohibiting whatever Hermione is doing.
  • Squirtle in Ashes of the Past decided to one up Gary's Blastoise and his Mega Evolution and created Squirtlite, a Mega Stone for Squirtles. That's right, Squirtle created his own Mega Evolution. However, upon reverting back to normal the Squirtilite explodes in a massive burst of water. Averted as Squirtle can simply create another one until he figures out how to stop the Squirtlite from destroying itself after use.
  • Invoked in Avenger of Steel when X-23, Rogue and Kitty Pryde had to fight a group of Silver Samurai; X-23 notes at one point that any strategy she uses against one won't work on others as they'll anticipate what she's doing.
  • Basically applies in The Corrupted Innocent when Bela learns that her status as an unbroken Seal means that she is essential "immune" to Lucifer's powers; just as he couldn't break the Seals himself, Bela is basically immune to direct assault from Lucifer's powers (he can throw things at her but he can't attack her directly), and he's also unable to read her mind or sense her presence with anything but his human senses. However, Castiel warns Bela that Lucifer will be on his guard once he knows about her immunity, so Bela decides to take care when confronting Lucifer, waiting for the right moment when being able to take action against Lucifer and catch him by surprise will be genuinely useful, as opposed to just buying them the advantage for that moment and never again.
  • Facing the Future Series:
    • This was actually the trigger for the whole series. Clockwork knew that when Dark Danny eventually escaped his imprisonment in the Fenton Thermos, since he now existed outside of time and didn't have to worry about harming his existence while fighting Danny, Danny wouldn't have the edge he had against him the last time they fought, requiring Clockwork to bring in someone who could do the job. Namely Danny and Sam's future selves from the current timeline, the latter of which is now half ghost.
    • In "Trial By Fire", Undergrowth attempted to invoke this by bringing in evergreen trees that could withstand Danny's ice powers. It only partially works.
    • As shown in "Laws of Attraction", Walker clearly learned from his past experiences of humans being intangible in his prison, so he had a special wing constructed for human prisoners. The only thing that messed it up was Sam's new ghost powers.
  • Fallout: Equestria: Alicorns have a whole suite of powerful magical abilities, plus a Hive Mind. Therefore, any time Littlepip finds a way to trick around their impregnable shields, next time they're ready for it. Stealth is the preferred method of dealing with them, but it's not always an option since they're often the ones ambushing her.
  • Harry Potter and the Natural 20: Milo is a D&D-style wizard and a massive munchkin, so he loves coming up with inventive ways to accomplish things using methods that should not, really, work like that. note  He's fully aware, however, that reality itself will quickly thereafter come up with a rule change that makes the trick unworkable, so he only gets a single shot.
  • It's essentially right there in the title of Lightning Only Strikes Once, which opens with Clarke climbing to the top of Polis Tower after Lexa's death, being struck by purple lightning, and finding herself back on the day when the dropship landed, with Lexa also awakening with her memory of the future intact. At the fic's conclusion, Clarke and Lexa climb to the top of the tower on the date when Clarke was struck by lightning in the original timeline and make plans regarding how they'll use their third chance, but when nothing happens they accept the whole experience as a one-off event and continue their current lives.
  • In Luminosity, Elspeth's Exposition Beam power can be weaponized by sending a massive amount of memories to someone at once (specifically, all the memories Aro has ever read), but this can only be used on any given target once. Future attempts do essentially nothing, because the person receiving the memories would have already received them.
  • Marionettes: The first time Trixie faces Gear Shift and Cover Story, she covers the floor with ice to make them slip. In their second encounter, when she tries it again, they're wearing winter horseshoes that allow them to walk on ice.
  • Pokémon Reset Bloodlines:
    • During the Melemele Grand Trial, Gladion notes that Kahuna Hala, while taken off-guard by Velvet's planned strategies against him, quickly adapts to them and finds ways to counter them.
    • Ash finds himself on both ends of this trope at different points. During his gym battle against Giovanni, the latter's Steelix uses Block to prevent Ash's Yanma from switching out. By the Indigo League, Ash has taught Yanma U-Turn, a move that allows the user to hit the opponent and switch out with a partner, allowing it to bypass Block during the second round. However, in the next round his opponent has several Pokémon who know the move Pursuit, which doubles damage on retreating Pokémon, including switching moves like U-Turn, preventing Ash from using this strategy again.
    • Similarly, in both his battles against Paul, Gary Oak finds himself confronting Paul's Jynx who tries to use Mean Look to prevent switching. The first time it works against his Pidgeot, but the second when he uses it against Porygon, the latter is able to escape using Teleport.
    • Pikachu reflects at one point that he and Swellow often tried to recreate "Thunder Armor" after that move helped them achieve victory over Tate and Liza, but those two could never make it work again, Staraptor couldn't master it either, Unfeazant wasn't interested in trying it, and he didn't have the chance to try it with Fletchling before the reality reset.
  • Rosario Vampire: Brightest Darkness Act III: While the group is fighting Kuyou in chapter 41, Mizore and Kurumu manage to land a blow on him with their duet. In chapter 42, when they try the attack again, Kuyou isn't about to let it happen twice and disrupts the attack by throwing Moka at them.
  • In the Merlin fic "Shades of Destiny", Merlin is able to bring Arthur back to life after the Battle of Camlann by pleading with the Goddess that he and Arthur need to form Albion and there has been enough death to justify restoring this one life, but Merlin senses a warning from the Goddess even as Arthur is restored that he'll only be able to get away with such a resurrection this once.
  • In the Marvel Cinematic Universe/Harry Potter crossover "Strange Potter", when Doctor Strange purges the horcrux from the infant Harry Potter, he soon realises that his actions have granted Harry the ability to wield chaos magic similar to the Scarlet Witch. Wong observes that such a feat should be impossible as nobody can wield all those magics at once without exploding, but Strange speculates that it was due to a combination of factors such as Lily's protection still being fresh, Harry's natural magic, the dark energy of the horcrux, Strange's own powers, and the natural significance of Halloween to their culture. Strange also explicitly notes that he doubts he could do such a thing again without it being fatal to the subject, as all those events coming together so perfectly was essentially a fluke.
    • On a smaller scale, after Natasha Romanoff marries Sirius Black, an extensive treatment of potions and spells allows her to give birth to a son, Regulus, but the healers all state that it's unlikely she'll be able to have another child as healing organ damage like that is very difficult.
  • Temporal Irregu Rarity: Twilight's plan to do time travel experiments is made more difficult by how the time travel spell only works once per pony / person:
    8. Obstacle. I can't do this as the spell only works once for any pony. I need the help of a friend who can work magic and pays attention to details. (Rarity!)
  • This Bites!: Franky runs into this problem when trying to push Monster Point Chopper into the sea thanks to Chopper's enchanced intelligence making his normally animalistic form far more adaptable than canon. Any attacks that Franky uses will only work the first time, as Monster Point Chopper will then come up with a strategy to counter it (such as dodging the cyborg's Weapon Left or blocking Fresh Fire with his hooves).
  • In The Weaver Option Taylor's forces are able to successfully kill Slaanesh during the razing of Commorragh. Afterwards Taylor is warned that they only succeeded due to the very unique relationship between Slaanesh and Commorragh. The other Chaos Gods are both better protected and now on-guard against similar strategies.
  • In an AU retelling of the ending of My Little Pony: Friendship Is Magic episode "Bats!" entitled "You Look So Sexy This Way", it's revealed that the spell Twilight used on the vampire fruit bats can only affect a subject once. However, the attempt to return Flutterbat to normal only restored Fluttershy's senses, with her body still being that of a batpony, and because Fluttershy receiving the rebound from the bats counted as being cast, the spell would no longer work on her, leaving her a batpony permanently.

    Film — Animated 
  • The omniscient Oracle from Aladdin and the King of Thieves is "bound by the Rule of One: one question, one answer". She knows everything and will answer one question to any person who asks. After, she will never answer another of their questions (much to Iago's frustration).
    Jasmine: What were they after, the gifts?
    Aladdin: Not all the gifts. This is what the King of Thieves wanted. (Holds up the mysterious scepter he wrestled from the King of Thieves during the chaos)
    Iago: With all the other great stuff in here, why go for this thing?
    (Suddenly, a blinding light emerges from the staff and it floats out of Al's hand. A voice rings out as a visage of a woman appears in the air)
    Oracle: Your question is mine to answer! The King of Thieves sought my sight to find the Ultimate Treasure.
    Iago: Did someone say "treasure?"
    Aladdin: Genie?
    Genie: Hmm...Looks like an Oracle.
    Oracle: I see all that has been, and all that will be.
    Genie: Uh oh, uh oh, definitely an Oracle, tells the future, uh oh. (back to normal) Girlfriend, where were you registered?
    Iago: Okay, you know all, so tell all. Where is the treasure? You know, the ultimate one?
    Oracle: I am bound by the rule of one. One question, one answer.
    Iago: I only want one answer! WHERE IS THE ULTIMATE TREASURE?!
    Oracle: You have already asked your question.
    Iago: You mean before? Oh, uh, that wasn't a question! That was uh...thinking out loud!
    Genie: (grabs Iago) VERY loud!
  • In Final Fantasy VII: Advent Children Complete, Cloud Strife uses Omnislash in an attempt to finish off Sephiroth the same way as he did in the original Final Fantasy VII. Unfortunately for him, it backfires spectacularly, because Sephiroth is more than ready this time. Instead, Sephiroth's the one who makes a repeat performance by skewering Cloud through the stomach like he did during their skirmish in Nibelheim years before when Cloud goes in for the final slash. Sephiroth even takes the time to mock him for it, before showing his wing and stabbing Cloud multiple times in mid-air with Octaslash.
    Sephiroth: "Is this the pain you felt before, Cloud? Allow me to remind you. This time you won't forget."
  • Hotel Transylvania: The monsters of Transylvania can only "zing" once in their whole life. Subverted in the third film however.
  • In The Incredibles, The Omnidroid is a learning robot, and combined with Syndrome's constant upgrades, it's able to defeat superhero after superhero, with anyone who defeats it getting killed by the next model. We even see Mr. Incredible attempting a "jump over the robot" avoidance maneuver twice and being completely thwarted on the second attempt. His Improvised Weapon of the Omnidroid's own detached claw only gives him one chance to take it out.
    Bob: What are you waiting for?
    Helen: A closer target! You've got one shot!
  • Suicide Squad: Hell to Pay features a 'Get out of Hell' card as the main plot point, hinted to be the only one in existence and sought after by multiple dying and concerned about death parties to bypass punishment in death. It ends up being used up by Bronze Tiger when Deadshot leaves it on his dying body, though Amanda Waller is initially unaware of this when Deadshot gives it to her, she finds out in the tie-in comic that she had been duped. The comic focuses on her attempt at finding the second best thing available, a Key that also bypasses eternal damnation but doesn't necessarily sends someone to Heaven like the Card, and its also even harder to find.
  • In Turning Red, the ritual to seal the panda spirit only works during the first red moon after it manifests, and the change is permanent if that opportunity is missed. There is a slight loophole for those have previously sealed their spirit, allowing them to do so again under the same conditions if the spirit is released.

    Film — Live Action 
  • The Amazing Spider-Man 2: During his first battle against Electro, Spider-Man hits him with water, defeating him. By the time Spidey uses the trick again, Electro had already figured out a way to create a barrier to protect himself.
  • Back to the Future Part II: To prevent Jennifer from asking too many questions about her future, Doc uses a sleep-inducing device to tranquilize her. Unfortunately, this causes a minor crimp in his plan to have Marty take his son's place at a meeting with Griff as the inducer didn't have enough power left to knock Marty Jr. out for a full hour, resulting in him showing up.
  • Back to the Future Part III:
    • Buford Tannen has a gun hidden in his hat, but it's so small that it can only carry a single bullet, and it's foiled when Marty uses a Frisbee Pie Pan to deflect his one and only shot.
    • The plan to get the DeLorean up to 88 MPH with the train. They have only one shot, and Doc clearly states that after they pass a certain designated point, "it's the future or bust".
  • Deadpool 2: Deadpool asks Cable why he can't use his time travel device to just keep bouncing around time until he gets everything right. Cable says his device only has enough charge left for one more jump, which he needs to get back home.
  • In Gamera vs. Barugon, the humans goad Barugon into firing his rainbow beam at a giant mirror, which bounces back and knocks him down. When the humans try it again, Barugon realizes what is going on and instead attacks them physically. He doesn't use his rainbow beam for the remainder of the film, except once out of desperation when Gamera kills him.
  • Godzilla:
    • In Gojira, the Oxygen Destroyer is a one-shot weapon used to kill Godzilla, and its creator ensures that it can never be reproduced by destroying his notes and killing himself. In Godzilla vs. Destoroyah, the device turns out to have mutated dormant Precambrian organisms into another Kaiju, leading the humans to come up with an elaborate plan to lure Godzilla into a fight with it.
    • In the first of the films featuring Mechagodzilla, Godzilla was able to defeat his Evil Knockoff by tearing off his head, removing the controls and cameras that let the mechanical monster keep moving. The second time they faced off, Godzilla repeated the move and was shocked when a second, smaller head emerged from the gap and blasted him with lasers.
    • In Godzilla (1998), the military first manage to lure Godzilla out of hiding by using a huge pile of fish as bait. After they bungle this attempt at killing Godzilla, they try again, but place the bait in the middle of Central Park this time, where Godzilla will be completely exposed. Unfortunately for them, Godzilla doesn't fall for it twice and stops short before turning back and running away.
  • Done in Gremlins 2: The New Batch with the gremlins' lethal weakness to sunlight, which ended up being pivotal to destroy Stripe in the first movie. First, Brain Gremlin injected the Bat Gremlin with a shot of genetic sunblock to allow it to roam outside and inform the others when the sun had setnote . Then, when the heroes concoct an elaborate scheme to get all the gremlins into the tower lobby and expose them all to the sun in one shot, it unfortunately starts to rain, which not only blocks out the sun, but would mean the hoard would multiply like mad if they went out in it.
  • Tony Stark/Iron Man's wrist-lasers in Iron Man 2. He's seen ejecting the thing's burned out battery after use. Lampshaded by Tony himself when Rhodey says he should have started with that: "It's a one-off."
    • And then averted in the next movie, when Tony uses the Mark VII suit in the climax: not only do his wrist-mounted lasers now have three beams, but after he uses them, they retract into his gauntlet. Since Tony's suits get more evolved with each film, he seemingly found a practical way to make the thing's battery not fry after one use.
  • The aptly-named "Henshin One-Shot" from the Non-Serial Movie of Kamen Rider 555 lets a normal human henshin into Kamen Rider Kaixa exactly once. And that is because instead of the user suffering the after-effects, it dissolves the Kaixa Gear by overclocking.
  • In Krull the seer known as the Widow Of The Web can protect vision seekers trying to enter her domain, in the center of a giant spider web, by turning over a large hourglass which immobilizes the giant spider guardian while the sands fall. We learn that leaving is impossible, because "it can be turned only once. That is the lure of the web."
  • In Man of Steel, the first time Superman and Zod fight, Zod's helmet gets broken and subjects him to Sensory Overload. By the time they have their rematch, Zod has learned to focus his senses.
  • In the 1999 Horror Comedy film Monster!, a town is trapped by a curse so that the title creature of a popular in-universe movie franchise that somehow escaped into the real world and every three years, it resurrects. As it runs on horror movie logic, it can't be killed the same way twice and thus a new way of killing it is needed each year.
  • Mentioned in Mud. Mud was bitten by a snake as a child and had his life saved by having an antidote administered in time. Unfortunately since the antidote is made of horse blood, it's something the body will recognize as a foreign material after being administered once and reject...meaning if bitten again there will be no way to save him and he will die.
  • Pacific Rim: This is actually the main reason Gypsy Danger's Armsword is used as a secret weapon. The Kaiju are all connected, with information one wave learns during their attacks sent back to the Kaiju leaders while designing the next waves. This allows them to analyze the earth tech and lets them come up with ways to neutralize them. It is this, combined with the increased number of attacks, that puts humanity in the bind that it is in by the movie's start.
  • Jack Sparrow's pistol in Pirates of the Caribbean: The Curse of the Black Pearl. When he was marooned, his former crew gave him a gun with one bullet to kill himself with. Indeed, he only fires the gun once in the film.
  • Brought up in Species II with Sil/Eve's alien race. If they survive being exposed to a disease, after healing, they immediately develop an immunity to it, leaving it ineffective later on.
  • Star Trek: Insurrection features a perfectly justified and logical case. The Sona's subspace weapons create a subspace tear that threatens to destroy the Enterprise. Riker and Geordi conclude that ejecting the warp core and detonating it in the tear will seal it. It works perfectly, but as Geordi points out they don't have another warp core, and the Sona can always do it again. Fortunately, Riker thinks of a way to keep them from doing so.
  • Dodged around like an Old-School Dogfight in Star Wars, when the Empire makes a new Death Star that, when completed, will be immune to the tactics that allowed the destruction of the previous one — unfortunately, it's only half-finished when the heroes get to it, and they simply have to repeat the same "single ship in a tight corridor" tactic inside the weapon to launch torpedoes into the core. That goes out the window when they find that the villains put up a force field around it. And the force field projector was heavily guarded. Sure, the Rebellion would have a shot if they destroyed the shield generator... but they weren't in very good shape. There's the indigenous population of the moon it's on, but they're just Ewoks, what could they...shit.
  • Richard Donner's cut of Superman II averted this trope by applying the same time travel reset button as the first movie, only in an even stupider way. More to the point, it links the freeing of the Phantom Zone criminals to Superman's use of this in the first movie tying into a warning Jor-El had given him about playing god with time. Superman did it the second time to fix the original mistake.
  • In Tremors, each trick used to defeat a graboid will not work on the next one, because the creatures are too smart and adapt just too damn fast. For example, they kill one by tricking it to swallow a pipe-bomb, but when they try on a second one, it spits the explosive back at them. The trend continues to reappear throughout the sequels.

    Literature 
  • Aesop's Fables: In "The Dog and the Wolf," a dog is caught by a wolf and about to be eaten. The dog tells the wolf that while he's too skinny at the moment and won't taste good, in a few days his master will hold a feast and give him all the scraps, and the wolf can then eat him while he's nice and fat. The wolf agrees. When he comes back a few days later, he finds the dog sitting on the roof of his master's house. The wolf says, "Come down, my friend, don't you remember our agreement?" The dog says, "My friend, if you ever catch me on the ground again, don't wait for any feast."
  • The Beyonders: If Maldor sends out a torivor to duel, it's all but guaranteed to kill whoever he sent it after. However, once the torivor has killed its mark, it is freed from the bindings on it and can return to its native realm. Since Maldor has neither the power nor the knowledge to summon more torivors, he usually sticks to sending them out to spy.
  • Biggles found himself fighting Sky Pirates targeting bullion shipments in Biggles and Co. The first time they hit his aircraft, he thwarted them with a false floor in the aircraft and some decoy crates full of lead... with some explosives wired to go off when the lid was lifted. The second time it happened, the air pirates immediately went for the secret compartment... And got another load of lead ingots because he'd put the real gold in the main cargo hold. The third time, the now very annoyed air pirates discovered they'd forced down an unloaded decoy aircraft. That didn't work quite so well because the air pirates had an inside source who'd hidden a smoke bomb in the latest consignment.
  • Book of Swords: Throw Farslayer with a target in mind, and it will strike down that target no matter where they are... and it will then stay there in their corpse for someone else to pick up.
  • Bruce Coville's Book of... Spine Tinglers: The gate in One Chance only works once for each person; if they don't go through, they can never summon it again.
  • In the ninth Ciaphas Cain book, an Imperium astropath discovers how to project a psychic field that jams the Tyranid Hive Mind, turning the tide of a major battle. Unfortunately, the strain burned out the captured Tyranid cortical node that was generating the jamming signal, and it will be very hard to find another one so nearly intact.
  • In Dragon Bones, the heroes defeat the villains by killing Oreg, who is sort of a Genius Loci to castle Hurog, while the villains are inside castle Hurog. The castle collapses. This obviously only works once, as Oreg is no longer bound to the castle, so even after it's rebuilt, it can't be repeated.
  • Ender's Game has a strategy winning a training battle that is discussed to Only Work Once (it is technically an exploit of the battleroom rules). It works. A similar strategy comes into play in the end battle, recalling that moment.
    • Ender is constantly challenged by the teachers, who keep putting him in situations that prevent the use of old tactics, necessitating him to come up with new ones on the fly. Not only that, but the other armies keep adopting his tactics, so he can't use the same ones anyway.
  • Leprechauns in the Fablehaven series cannot be caught by the same trap twice. Patton Burgess not only caught one five times with five different traps, he had more traps ready for anyone who wanted to try it.
  • In the Honor Harrington novel On Basilisk Station, we are introduced to the grav lance, which allows even a light cruiser to take down a superdreadnought's sidewall, but has a very short range, a quarter that of standard energy weapons. Getting it to work requires immense sneakiness and the enemy not looking out for it. It works the first time because the OpFor was not expecting it, but in subsequent exercises the other side knows how to look out for its attempted use. It is these repeated failures that get Honor the eponymous Reassigned to Antarctica. In the final battle against a Havenite Q-ship that outmasses even a super-dreadnought, she manages to pull off another successful use.
    • This is stated by Harrington to her students concerning her escape from Hades: the stunt she pulled to take out the State Sec convoy coming to retake the planet had so much that could have conceivably gone wrong, depended on the enemy being extremely sloppy in monitoring their sensors, relied on having detailed information regarding their approach that would be near-impossible to have in any other situation, and she had absolutely no other choice except to try it.
    • Subverted in Storm From the Shadows, as the Mesan plan involving New Tuscany is, and is lampshaded as, a repeat of the plan used in Shadow of Saganami. However, the second attempt succeeds in its intended goal of provoking a war between Manticore and the Solarian League.
  • In I Shall Wear Midnight, Tiffany is told that while the Cunning Man has been defeated before, learning how it was done won't help her and she'll need to devise her own strategy against him. The reason is that he won't fall for the same trick twice — he's cunning, after all.
  • A version of a bluff that only works once in Harry Harrison's Invasion: Earth. When the crew of an alien ship threatens to drop radiation bombs on Earth cities, the military replies that they have a secretly-developed laser weapon trained on the ship. The aliens try to call their bluff, but their ship promptly explodes. Turns out there is no laser weapon after all, but the soldiers simply planted charges on it earlier (interestingly, no one mentions the problem of a ship filled with radioactive material exploding in Earth's orbit). The remaining alien ship, after a few more words, wisely decides to leave and not challenge the bluff.
  • In Edgar Rice Burroughs' John Carter of Mars novel A Fighting Man of Mars, the hero obtains invisible items from the villain for some effect. However, they lose them. You see, the invisibility was always in effect.
  • Tolkien's Legendarium:
    • This is a matter of some contention among The Lord of the Rings fandom, among whom there is a vocal minority that considers Aragorn's use of a seemingly invincible undead army in only one battle (rather than throughout the war) to be a Headscratcher verging on a Wall Banger. Debates about whether the Exact Words of their oath would have allowed him to demand longer service from them can go (and have gone) on for dozens of pages in various internet fora. The popular consensus is that the undead army was not magically compelled to obey Aragorn, but did so voluntarily as he was the only one who could release them to pass on to a more standard afterlife. If they'd gotten it into their heads that he did not intend to release them, they could very well have gone over to the other side, so he decided that it was better to be safe than sorry. YMMV on whether this explanation makes this a legit example or is merely a convenient bit of Fan Wank. It should also be noted that it is never made clear (in the books at least) if the army of the dead can physically hurt people, as the only army they deal with they simply terrify into fleeing. If they could not actually attack people, once the psychological impact of them wore off, their usefulness would be greatly reduced. Regardless, they demanded to be released after a single battle, and he complied.
    • In The Silmarillion, it's a repeated plot point that certain great works can only be made once and never again. When Ungoliant kills the Two Trees of Valinor, Yavanna is unable to create them anew. Likewise, Feanor states that if the Silmarils were destroyed (which might have let Yavanna revive the Trees using the light from the Silmarils), he would never be able to make something of equal beauty again.
  • In William R. Forstchen's The Lost Regiment novel Union Forever, a large naval battle between the Cartha led by Cromwell's ironclad Ogunquit and the Roumans led by Keane's hastily-constructed ironclads is ultimately won by the latter despite the former seemingly winning moments before. Why? Because reinforcements arrive for the latter in the form of what appears to be a gigantic ironclad with three long-range guns that look like they could turn the Ogunquit into wreckage. In fact, it's a barely-working small single-cannon ironclad with bits of metal and wood attached to the front and sides to make it look larger and wooden logs sticking out to make them look like cannons. It's specifically stated that this trick will not work again.
  • The Marvellous Land of Snergs: Subverted. Gorbo is given one invisibility cap, one stick which transforms into a sword capable of cutting anything, and a pair of shoes which grant super-running speed. He is warned that the cap loses power after ten minutes, and the stick and the shoes after one use. The subversion comes when it is revealed that Gorbo was tricked: those objects are not magic at all.
  • In John Varley's novel Millennium (1983), once a time traveler visits a time, that specific time period from arrival there to returning to your own time can never be accessed again.
  • In Romance of the Three Kingdoms Zhuge Liang's use of the "Empty Fort Strategy". Specifically, he orders his few hundred soldiers to dress as civilians and all the city gates to be thrown open. Sima Yi is wary of Zhuge Liang's strategic brilliance and assumes it to be a triple bluff as Zhuge Liang's plans never leave his army open to this kind of risk. Afterward, Zhuge Liang remarks that the only reason the trick worked is that Sima Yi never imagined that he would try a bluff like that, and now that he has, Sima Yi's too smart to fall for it ever again.
  • Early in the Shannara series, Allanon mentions that certain powerful works of magic can only be performed once and then never again. This is the reason why the heroes of the various books have to spend so much time hunting down or protecting one MacGuffin or another — if, e.g., the Sword of Shannara goes missing, you can't just forge a new one to replace it.
  • Near the end of Starsight, Spensa is able to cause a delver to stop its attack by cytonically linking to it and showing it that the creatures of the somewhere are people with thoughts and feelings and value. In Cytonic, she tries to do the same to other delvers, only to find out that they have rewritten their minds to make themselves incapable of developing empathy towards the denizens of the somewhere.
  • In the New Jedi Order series of Star Wars novels, someone comes up with the brilliant idea of using the Centerpoint Station superweapon to destroy a Yuuzhan Vong fleet. Unfortunately the heroes get righteous on the guy trying to fire the weapon, and cause him to misfire. The weapon destroys a major Galactic Alliance fleet, and Centerpoint powers down, unable to be used ever again.
    • A milder version in the same series, Jedi Knight Corran Horn has a "dual-phase" lightsaber, which allows the blade to extend in length. At one point, he surprises one of a pair of Yuuzhan Vong warriors by suddenly extending the blade, impaling him. He monologues to the other warrior (who may or may not have been able to understand him) that he knew he'd only be able to use the trick once, and chose to use it on the obviously less-skilled warrior, since he'd be more likely to fall for it.
  • Piers Anthony's Xanth series had the character Surprise Golem that had the magic talent of all magic talents. Her talent is to have whatever talent she wants at the moment. It was soon discovered she could only use each talent once, but she could achieve the same results by using variations. Which makes it not much of a limitation at all, though some specific effects she might want to produce will naturally have more variations available than others.
    • In The Dastard Surprise finds out that she can perform the same spell twice with a significant period of time between the two only to have her discovery erased from time by The Dastard.
    • Talents themselves are a form of this in Xanth. Each person has a unique magical talent, and it's strongly implied (if not outright stated) that talents will never reoccur. Once a person with a specific talent dies, no one else will ever have that specific talent ever again. Talents can overlap in their effects (with Surprise's talent, by definition, overlapping with everyone else's), but no two are ever exactly the same.note 
    • This is how all of the Adepts' spells work in Anthony's Apprentice Adept series, with the same variation loophole.
  • In Godfather Death, Death gives his godson a magical herb to make him a famous physician. If Death is standing at the head of a patient’s bed, the physician can cure any illness they have with the herb. When the physician sees that the king is destined to die because Death is standing at the foot of the bed, he turns the bed around so that Death is standing at the head of the bed, letting the physician save the king's life with the magic herb. Death is outraged at this betrayal but spares his godson's life out of love, warning him that if he ever pulled that stunt a second time, he would pay the consequences. When the physician does the same trick to save the life of the king's daughter, Death makes good on his threat and takes the physician's life.
  • Universal Monsters: In book 2, the method that returned Dracula to his film (a modified camcorder, equipped with a reversed version of the program that fixed the faulty film projector) doesn't work on the next monster at first; the trio quickly figure out they have to modify their camcorder for each monster or group of monsters.

    Live-Action TV 
  • In an episode of Andromeda, the Nietzscheans are trying to erase the AIs of captured High Guard warships. They have finally created a device that can do that without any physical damage, and manage to delete the AI of the Wrath of Achilles. Dylan captures the device and keeps it in storage. A year later, a rogue AI named Gabriel hijacks a newly-built sister-ship of the Wrath of Achilles (Siege Perilous class), and Dylan uses the device again. However, Gabriel has been aware of the device's existence for this whole year ("For an AI, it's an eternity") and has managed to devise a countermeasure. To be fair, though, it would still probably work on any AI not aware of the device's existence.
  • Some particularly gutsy BattleBots competitors have chosen to equip their bots with weapons that can only be used once per match:
    • Chrome Fly has an otherwise fairly standard design, but it has a companion drone that drops a cylindrical weight. As the drone cannot retrieve this weight and can only carry one at a time, it can only use it once. As luck would have it, the one time it dropped the weight in its entire career, it missed.
    • Double Jeopardy has a cannon as its main weapon that shoots a similarly shaped, sized weight, though at about 190 miles per hour (or about 305 kilometers per hour). Like Chrome Fly's drone, it can only shoot it once, as it's not equipped to reload another slug. Unlike Chrome Fly, it managed to hit its opponent Gamma 9 on its initial match, though Gamma 9's operators were never directly in front of Double Jeopardy whenever possible, which meant it didn't fire that cannon until right before it was knocked out.
  • Breaking Bad: In the episode "Bullet Points", a rival cartel attempts to hijack a Los Pollos Hermanos truck (which is hiding shipments of high-quality meth), but Gus anticipated this by having Mike hide in the cargo box. The hijackers attempted to prepare this possibility by first raking the cargo box with bullets, but Mike lies low enough to avoid all but a slight nick to the ear, and then shoots and kills the would-be robbers when they think it's safe to enter. The episode "Cornered" has the same thing, with two guards sitting in the Los Pollos Hermanos truck cargo in case it gets robbed, but this time the hijackers simply lock the doors and reroute the truck's exhaust into the cargo box to asphyxiate them (although this wouldn't work in reality, for a number of reasons).
  • Doctor Who:
    • "Bad Wolf"/"The Parting of the Ways":
      • Jack jury-rigs a BFG from the Defabricator and his Compact Laser Deluxe. However, it only has enough power to kill one Dalek, due to the makeshift nature of the weapon. When it returns in "The Stolen Earth"/"Journey's End", Jack's had the time to upgrade and fine-tune it so it no longer dies after one shot.
      • Rose absorbs the Time Vortex, effectively making her a God, allowing her to reduce the Daleks to dust with a wave of her hand and bring Jack back to life (forever, as it turns out). However, the side effect is that it very nearly kills her, and causes the Doctor to regenerate after he absorbs the energy from her. In the subsquent Christmas special, Rose tells Mickey she has the feeling it would break the universe if she tried it again.
    • The power the Doctor gains over the Carrionites in "The Shakespeare Code" when he uses the species' name to banish one of them only works once. Oddly, though, it only works once AT ALL, rather than only working once on each member of the species.
    • "Resolution": It's implied the reason the villain evades the Doctor's attempt to roast it inside its own casing with repurposed microwave parts is because this is basically the same way it was first defeated on Earth in the ninth century.
  • The Good Place:
    • After Eleanor works out that "The Good Place" is actually a psychological Hell for her and three other humans, she thwarts Michael's plan to reset their memories by writing herself a note and hiding it in Janet's mouth. While this allows her to uncover the truth much quicker without her old memories, Michael simply reboots their memories again, and checks Janet's mouth as he restarts the neighbourhood.
    • Partway through Season 2, Jason prevents demons from capturing him and his friends using a quick Molotov Cocktail and a Battle Cry. Next season, he tries the same thing to defeat another group of demons — only for one demon to clamp a hand over Jason's mouth while another douses the Molotov.
  • Goosebumps (1995): In Part 3 of "Chillogy", Jessica, Matthew, and Todd are fleeing from Karl. Jessica's first instinct is to re-use the Telephone Teleport that she had previously used to escape Karlsville, but unfortunately Karl is already waiting for them. They are eventually sucked out of the town by a vacuum cleaner.
  • iCarly: In his first episode, Carly, Sam, and Freddie realize that all they really need to do to stop Nevel is tattle on him to his mom (since he is only 11). This is handwaved in his next appearance where they mention that his mom is going out of town and will be unreachable for a while. After this, it is never brought up again.
  • Kamen Rider Ex-Aid sees the villainous Masamune Dan/Kamen Rider Cronus unlock the Reset function of the Gashacon Bugvisor II when the Master Gashat for Kamen Rider Chronicle is destroyed, allowing him to undo its destruction and Ret-Gone Emu's Hyper Muteki Gashat, costing the Doctor Riders the one power that can counter his Pause. When the Riders manage to beat Graphite, allowing them to summon Gamedeus so they can defeat it and clear Rider Chronicle, he tries to use Reset again...and Emu, thanks to Kuroto's tireless work, counters with a second copy of Hyper Muteki and the Save Energy Item, which saves the progress of the Riders, making Reset completely useless exactly one episode after its debut.
  • Kamen Rider Wizard has the Phantom Phoenix who, through a combination of Resurrective Immortality and Came Back Strong, No Sells the Finishing Moves which previously destroyed him. Unable to truly kill Phoenix, Wizard only neutralizes him permanently by kicking him into the Sun, where he is contained in a state of being perpetually incinerated then reconstituting instantly over and over again. However, bonus material does suggest that Phoenix may eventually overcome even that fate, though it may take a million years for him to surpass the Sun's intense heat and gravity.
  • In an early episode of Pee-wee's Playhouse involving a thunderstorm, Randy shows Pee-Wee how to prank call someone by calling up a woman on the picture phone and asking "Is your refrigerator running?". When it's Pee-Wee's turn to do a prank call, he calls up the exact same person with the exact same joke. She obviously doesn't fall for it the second time.
  • Power Rangers/Super Sentai
    • Power Rangers S.P.D.: Kat Manx is given a special Morpher that allows her to transform, but only has one charge, and it only lasts an hour of transformation time. She takes it and goes into battle as the Kat Ranger for the first and only time.
    • Subverted with her Tokusou Sentai Dekaranger counterpart Swan Shiratori, who can use her DekaSwan form whenever she wants, but makes a policy of only doing so once every four years (except in emergencies, as when she tried to transform in the finale only to be interrupted before she could do so). She transforms again in Kaizoku Sentai Gokaiger.
    • Juken Sentai Gekiranger has the Tenchi Tenben Da, or Heaven and Earth Disaster Strike. Heralded as the ultimate skill of Bruce E, Juken's creator, and called a technique that defies the very laws of nature. GekiViolet managed to recreate the technique through Training from Hell and managed to use it to land a One-Hit Kill on Genjuken warrior Gouyo, but when he attempted to use the same technique against Rio, who was the reason he learned the technique in the first place, Rio managed to easily counter the technique, having already seen it in action.
    • In Tensou Sentai Goseiger, Robogog's ultimate weapon was a world ending Wave-Motion Gun called Calamity Destruction, but it could be used once, and thanks to Buredoran, who intentionally didn't seal Gosei Knight's morpher completely, Gosei Knight was able to block the blast and stop it from destroying the world, leaving Robogog furious that his ultimate weapon had been wasted.
    • In Power Rangers Dino Fury, Ollie and Solon use the Legendary Ranger Database to read up on Lord Zedd, who was revived as The Heartless after the original had been purified and having captured the rest of the Rangers. Upon learning of Zordon's Heroic Sacrifice, the two quickly realize there's no way they could recreate such a World-Healing Wave.
  • Reaper had Sam, the main character, use vessels to catch escaped souls from hell. Each week's vessel was different, being an item related to what the escaped person had been sent to hell for.
  • Salem: For some reason, after Mercy's snake familiar is exorcised from her, she's now capable of staying in control of herself after Mary Sibley tries to put it back.
  • In the Star Trek: The Original Series episode "Let That Be Your Last Battlefield", Kirk, Spock, and Scotty initially manage to get Bele to give control of the Enterprise back by activating the ship's Self-Destruct Mechanism, which he complies with before the sequence is complete. Towards the end of the episode, after hijacking the ship again, Bele manages to burn out the mechanism, preventing them from using it again.
  • In Star Trek: The Next Generation, the Borg have the ability to adapt to phaser frequencies after a few shots. The obvious workaround for this is changing the phaser frequency to something they haven't adapted to. The Star Trek: Elite Force games explicitly addressed this issue by introducing the Infinity Modulator (or I-Mod) gun, which changes frequencies too quickly for Borg to adapt.
    • In the first level of the second game (based on the last episode of Star Trek: Voyager), the Borg adapt to the I-Mod as well by using a jamming field specifically designed to stop the I-Mod from firing. The player is forced to do the mission with regular weapons, using shots sparingly.
    • The I-Mod actually infinitely randomizes the frequency to such an extent that the Borg can't even adapt to the randomization algorithm normally used by phasers.
    • In the series itself, much is made of this trope when anyone is simply planning on fighting the Borg. They know that any possible advantage they can come up with will result in the Borg adapting to render it ineffective quickly afterward. Thus, they often hold back the advantage until it is most likely to be needed.
  • Discussed in the Star Trek: Deep Space Nine episodes "The House of Quark" and "Looking for par'Mach in All the Wrong Places", both of which feature Ferengi Quark forced to duel a Klingon warrior. When he was challenged by D'Ghor in front of the High Council, Quark was able to get out of the duel by throwing away his weapon and daring his opponent to kill him anyway, thus proving that D'Ghor was a dishonorable Klingon in front of the High Council and thus confirming Quark's allegations against him (he had accused D'Ghor of trying to dismantle a rival house through financial manipulation rather than open challenge). When he's subsequently challenged to a private duel against a Klingon bodyguard, Quark contemplates using the same strategy, but Worf points out this only worked last time because it was a public display of dishonor in front of the High Council; in the case of a private duel there's nothing to stop Quark's opponent from simply executing him anyway.
  • Stranger Things: In the second season finale, in order to free Will from the influence of the Mind Flayer they lock him in Hopper's cabin and turn the heat up to sweltering levels, as puppets of the Mind Flayer prefer cooler temperatures. Will's body goes insane, breaking his bonds and almost overpowering Joyce before finally burning out of his body. In the third season, the characters realize that Billy was similarly possessed by the Mind Flayer, and try a similar tactic tricking him into a sauna and even have Eleven with them as muscle. Billy, however, is naturally bigger and stronger than the adolescent Will, which made the process take longer, and being enhanced by the Mind Flayer made him a threat even to Eleven, which allowed him to escape. This was a sign that the growing Mind Flayer army was both especially dangerous and there weren't going to be easy solutions.
  • Supergirl (2015): Shortly after Kara arrived on Earth, she used her powers to save someone from a car accident. Her foster father Jeremiah covered by claiming she got lucky, but warns her that excuse is only going to work once. It's almost fifteen years before she finally becomes a hero, starting when she has to save her sister's crashing plane. As it turns out, the explanation didn't even work perfectly that one time. Rick Malverne, a friend Kara's age, was always suspicious after that incident and quickly put two and two together when Supergirl saved a plane with Kara's sister on it.
  • Supernatural:
    • In Season 7, Sam and Dean eventually acquire a Villain-Beating Artifact that can be used to kill an otherwise Nigh-Invulnerable Leviathan, but it can only be used once. They decide to target their leader Dick Roman, hoping that his army will collapse without him. When the weapon is finally used, it sucks both Dean and Castiel along with Roman into the monster afterlife.
    • Justified with the witch Rowena's unique spell to restore a spirit to life: everything about the spell itself is repeatable, but The Grim Reaper takes a dim view of cheating death, so will change the laws of nature to close the loophole as soon as she uses it.
  • Obfuscating Stupidity as a strategy in social game shows like Survivor. Part of the reason it only works once is that it relies on people not knowing who you are and only seeing the mask you put on in front of them. If say, you do this, get to the end or win, then return for an all-stars season a year or so later, your fellow players would know that you're not as dumb as you look. If you jump from one season directly to the next (such as Amanda&James, Rupert, Russell Hantz), then you'll still have the advantage of being unknown to your fellow players. That is, however, assuming the players are smart enough to see through it all. (Part of why Rob was able to get an easy victory in Redemption Island was because all his tribe members except himself and Kristina left their brains at home and thought Rob was going to take them to the finals.)
    • This was also Russell's downfall in said season. The first two times he played, he was unknown to the rest of the players. When he returned for Redemption Island, he wasn't put on the "Stupid" tribe and they saw him doing exactly the same thing.
  • In Tomica Hero Rescue Force the team combine all their vehicles into Great God Striker and use it's Super Final Rescue to destroy the Big Bad Batsu. Unfortunately it fails.
  • In UFO (1970), the invading aliens use a new superweapon in each attack. It fails not necessarily because it is flawed but also through bad luck. However, they never try it again although it still exists and might be devastating in another attempt.
  • The television series V (1983) was premised on this. The red dust which was all-powerful in stopping the Visitors at the end of the V miniseries was suddenly found to be ineffective in warmer climates. Also, re-application of the red dust wasn't an option since it was found that repeated exposures to the virus could be deadly to Earth lifeforms too over time (as opposed to instant death for the Visitors).
  • In the first season finale of Witchblade, Sara chooses to go back in time to the first episode, thus undoing everything that happened in the series so far. She is specifically informed that this will only be possible to do once, presumably to stop that ability from being a Game-Breaker.
  • In Wizards of Waverly Place, Alex defeats Franken Girl, the monster Justin created to guard his bedroom, after finding out that Justin installed his own laptop as brain and tricking the monster into shutting itself down with the "Control", "Alt" and "Delete" keys. Unfortunately for Alex, Justin brings Franken Girl back to life and adds a spell lock preventing Alex from using the same trick.
  • In the first season of Workaholics, the guys got rehired after threatening to expose their boss' illegal business practices. This is never, ever brought up again, even in the numerous following episodes where she bullies them or makes their lives difficult in some way.

    Myths & Religion 
  • In The Bible, Satan's Eden ploy was this. Yes, it struck an incredible blow against humanity, but it also exposed Satan as a deceiver who is Always Chaotic Evil. This is a big reason why Christianity's tone is so triumphant: there is nothing Satan can do to us that will be as bad as what he's already done, and even that didn't erase our intrinsic worth in the eyes of God. Notably, the next time Satan tried to tempt a representative of humanity, he was shut down hard.

    Professional Wrestling 
  • Bryan Danielson ended his best of five series against Homicide to get a shot at the Ring of Honor World Champion with a 100 rotation air plane spin. When he tried to use it again during the title match, Austin Aries slipped out of it after 30 rotations. Danielson's inability to take the title from Aries led to him going into voluntary exile from ROH until he knew he could do it.note 

    Tabletop Games 
  • Almost every RPG is open to this trope. The GM probably had a pretty good idea of how you are supposed to get past a bad guy but either hinted at it too subtly, the players were point blank oblivious to anything other than violence or hilariously botched rolls while trying to figure it out, they just don't get there. And that means that the GM either has to murder all the PCs or let them lash together a plan between themselves to leapfrog this particular station on the plot railroad. But only this time.
    • Alternatively players being what they are, they may put in WAY more time and effort into working out how to defeat the bad guy from a Rules Lawyer perspective than the GM hoped, and thus arrive at a fait-accompli that is irrefutable from a rules standpoint but not what he had in mind. Given the effort involved, the GM has to let it pass this time, but threats (or possibly rocks) are likely to be passed should they ignore the plot and focus on breaking the system in future.
  • Champions. The villainous robot Mechanon has automated factories around the world. Whenever he's destroyed, one of the factories creates him again, this time with defenses against whatever destroyed him. This makes it much more difficult or even impossible to destroy him the same way again.
  • In Chuubo's Marvelous Wish-Granting Engine, which has plenty of powers that are very draining if you use them more than once in a chapter or even once in a book, and a few (such as some forms of Reality Syndrome) that simply cannot be used more than once per chapter, the Salvation power from the Wounded Angel arc works once per campaign. It is the only power in the entire corebook with this limitation. To be fair, it's a strong power, enabling you to reshape the world to save someone for whom all is lost, but still!
  • Most of a PC's powers in 4th Edition Dungeons & Dragons only work once per encounter or once per day. At least they can be recharged between fights, though...
    • For arcane or divine spells, this is justified by encounter and daily spells requiring a minute or two or longer of memorization, preparation, and/or prayer to prepare. For physical powers, it's explained that they are so physically demanding or reliant on surprise tactics that your character can only perform (or get away with them) once. This is one of the main reasons why there's a Broken Base over this edition: some players find that it's not airtight, but in most cases it works under Rule of Cool; other players find this a ridiculous case of Fridge Logic.
  • The GURPS Player Handbook suggests the DM should reward a clever player who comes up with a new gambit by letting the trick work ... but only once. The example given is throwing sand in an opponent's eyes to blind him — might work once, but if it were really that effective all the time, "fighters would leave their weapons at home and carry bags of sand instead." Thus to keep the game balance, creative gambits should only work once.
    • In one of his Pyramid editorials, Steven Marsh said that he'd tried giving his players awesome abilities that could only ever be used once, and they never got used at all. Partly because players were always thinking that if they used it now, they might need it later, until not using it became a habit, and partly because it's just so much cooler to be the guy who could at any moment unleash their Ultimate Power than it is to be the guy who did that three adventures ago.
  • Pokémon Trading Card Game
    • During the Red and Blue era, there were three Pokémon cards (Base Set Farfetch'd, Koga's Beedrill, and Giovanni's Magikarp) that had attacks that could only be used once per game (even Benching that Pokémon doesn't let you use it again). Unfortunately, all three such attacks also had you flip a coin to see if that attack would do anything, with the once-per-game restriction applying even if that attack did nothing.
    • In the Sun and Moon era, there were Pokémon-GX, stronger Pokémon cards that had even more powerful GX attacks. The rule is that a player can only use one GX attack in a game.
  • Yu-Gi-Oh! has a few cards whose effects can only be activated once per game, a step up from the usual once per turn restrictions found on many cards. Though there are very few "once per Duel" effects, this restriction dates all the way back to 2003 with Twin-Headed Behemoth.

    Theatre 
  • In Wicked, Elphaba's control over her magic is limited, often gives unexpected results, and she can't undo a spell once it's been cast. This leads to problems throughout the story.

    Video Games 
  • In Ace Combat 7: Skies Unknown, in order to try to shoot down one of the Arsenal Birds, the Oseans sneak a team of engineers into Stonehenge deep within Erusean occupied territory to repair the remaining railgun that was spared by the ISAF in Shattered Skies, due to it having been knocked out by a meteor. However, because it had been rotting away in the desert for a decade an a half, combined with the fact that they power it up with a fleet of generator trucks, they’re only able to get one shot in. Fortunately, thanks to the LRSSG damaging the Arsenal Bird, they’re able use the railgun to hit and destroy the Arsenal Bird, which turns the tide of war into Osea’s favor.
  • Batman: Arkham City:
    • When Batman goes to Mr. Freeze in order to finish a cure for the Joker's, and his own Titan infection, Freeze ends up betraying him and starting a Predator sequence, during which each of the Dark Knight's repertoire of takedowns only works on Freeze once, since he'll begin nullifying their usage afterward (e.g. freezing electromagnets, using high-power jets on the rear of his suit, encasing railings, breakable walls/ceilings, etc.). To defeat him, Batman must employ five different takedowns to catch him by surprise. In New Game Plus Mode, this is increased to nine different takedowns, requiring even more careful planning of when and how to strike.
    • In the comic book tie-in Batman comes up with the idea of disguising the Bat-boat as a fishing boat to sneak into Arkham City. It works brilliantly... until he tries it a second time, where the boat winds up blown up with a rocket. Lampshaded by Batman.
      Batman: That worked a grand total of once.
  • Castlevania: Harmony of Dissonance: Skeletons can only throw their skulls once, since they only have one skull. It doesn't kill them, they can still throw bones after.
  • The console-only game (later ported to mobiles) Civilization Revolution only has one nuke in any single game. It's given to the player who builds the Manhattan Project wonder. It can hit any city or square on the map but leaves no fallout. Doesn't stop enemies from declaring war on you at the drop of a hat.
  • Command & Conquer series:
    • In the original game, NOD only had the capability to launch a single nuke (it was a lot more powerful than nukes in the later C&C games though). GDI's counterpart, the Ion Cannon had no such limitations.
    • In the Yuri's Revenge expansion of Red Alert 2, partway through the fourth Allied mission in Egypt you get one free use of the Psychic Dominator after you rescue Einstein from Yuri's clutches — he managed to sabotage it under Yuri's nose before your forces rescue him. He states it is unstable, though, and will self-destruct before you get a second use.
  • The call-in supertanks in Company of Heroes for the Axis factions, the King Tiger and the Jagdpanther. You get one per game, and God help you if Allied AT guns knock them out (and you don't have a Bergetiger to revive them). Then again, if the Allied players are still putting up a defense as opposed to screaming like a little girl, there's something wrong...
  • Disgaea: In the second chapter, Flonne summons a dragon to attack you, announcing that because she has to use a special item, she can only do it once — thus, after she joins your party, there will be no dragon-summoning.
    • This can be partially averted... by capturing the dragon she summons, allowing YOU to summon the dragon whenever you want!
    • And then it's entirely averted... In Disgaea 4, where both Archeangel Flonne and Fallen Angel Flonne have it as a move, with the same incantation. The former summons a normal dragon while the latter summons a zombie dragon.
      • For a more literal interpretation of this trope, Superboss Pringer X is this trope. Any special attack used against him will only damage him once. If you're fighting multiple Pringers, they all become to immune to the special move.
      • Tyrant Overlord Baal, in his battle in Dimension 2. Even normal attacks can be no-sold by him after he takes a hit, thus demanding your character(s) to have all of the weapon skills in order to win.
  • Fate/stay night: A problem when facing Servant Berserker. He's incredibly powerful, so to manage to damage him at all is quite an effort... but he has the God Hand Noble Phantasm, which allows him to revive himself 11 times, so you'll have to kill him twelve times to finally finish him off. Worse, he becomes immune to whatever it was that killed him last time, so you have to do it twelve different ways. Of course, there's nothing saying a sufficiently powerful attack can't take away more than one of his lives at once.
    • Fate/EXTRA CCC: Karna has access to one of the most powerful Noble Phantasms seen in the franchise: Vasavi Shakti, the spear granted to him by the god Indra. The spear has sufficient power to quite literally kill a god, and its raw destructive power far exceeds nearly all others. However, unlike most Noble Phantasms, Karna can only ever use this ability once, and he has to permanently give up his Armor of Invincibility to do it.
    • Fate/Grand Order: In her original life, Queen Medb from Celtic Mythology was assassinated by having a hunk of cheese hurled at her with a slingshot while she was bathing. During the Summer 2017 event, the heroes attempt to have Enkidu hurl a hunk of cheese at her while she is taking a shower. She deflects it and says she's developed a Spider-Sense for cheese.
  • In Fire Emblem games, items that are capable of reviving dead units (who would otherwise be subject to Permadeath) can only be used once. Such items also tend to be extremely rare, with some only appearing once in a given playthrough, so extreme care must be exercised in their use.
  • Owing to a programming error, the Dragon Zombie of Final Fantasy VII will cast its ultimate spell "Pandora's Box" at you only once — after that, no enemy will ever attempt the spell on you again (unless you start the game over). Your party can learn the attack for themselves, but if you didn't have an Enemy Skill material on them at the time, it's gone for good.
  • Final Fantasy XV has a retroactive version as of the release of Episode Ardyn. Two years before Noctis was born, Ardyn and Ifrit attacked Insomnia; after the playable happenings, Ifrit is watching as Ardyn tries to strike down King Regis, and gets impaled on Bahamut's Ultima Sword when the Bladekeeper interrupts. Thirty-two years later, when Noctis comes to Insomnia for the Final Bosses, he fights Ifrit again; this is the only time when Noctis is able to summon Bahamut to perform Ultima Sword, and Ifrit dodges every one.
  • Gems of War: One-Shot spells can only be used once per battle.
  • GOHOME: The griffin who will give you a lift back to your house will only do it at the beginning of the game. If you try and find it during the night, it will take off, meaning you have to get to the shrine by yourself.
  • Granblue Fantasy: Quite a few characters have skills that can only be used once per battle. Most notably, each one of the ten Eternal characters has an incredibly powerfull skill with an extremely long 10 turn cooldown before it can be used. In addition, some other characters have skills that grant them massive buffs but knock themselves out after a few turns, meaning anything you do with them until then will only have one chance to work in each battle.
  • In Guild Wars 2 the Pact is able to kill the Elder Dragon Zhaitan with a massed air fleet assault. Using the same tactic against Mordremoth sees the entire fleet destroyed in minutes. Discussed when Taimi later explains that each Elder Dragon has a unique weakness, meaning a new method will need to be used for each one.
  • Homeworld Cataclysm: The huge cannon you weld to your mining-vessel-turned-mothership has the problem of only working once before requiring major repair. The ship it's attached to is initially civilian, and energy conductors and heatsink systems suitable to power a cannon about a third of its entire size were not included in the original designs. Searching for them is a major plot point taking up several missions — though it does, eventually, give you a cannon whose reload rate doesn't include an inter-mission cinematic.
  • League of Legends features a purchasable item called the Seeker's Armguard (with a predecessor version called the "Stopwatch"). Most items in the game are meant to permanently upgrade your stats, and others are consumable items like potions and vision wards for general utility, and the Seeker's Armguard rests between both types — activating it puts its user in the "Stasis" effect, making themselves completely invulnerable for a few seconds while also making them unable to move or attack. Once it's used, the item becomes a "Broken Armguard" and can't be used normally for the rest of the game (not even purchasing new Armguards will help), so you better make the one use count. This can be mitigated by building either version of the Armguard into the more impressive Zhonya's Hourglass, which provides better stats and puts the "Stasis" ability on a resettable cooldown, but like most "completed" items, it's expensive and context-dependent.
  • The Legend of Zelda: Breath of the Wild:
    • Played with and zig-zagged when it comes to the plan of taking Calamity Ganon down. In the distant past, Calamity Ganon appeared and the Guardians and Divine Beasts played a vital role in defeating him, with the Hyrulian princess and a heroic knight eventually sealing him away. When a prophecy foretold the return of Calamity Ganon, King Rhoam had the Guardians and Divine Beasts excavated to recreate the circumstances of the ancient battle. Unfortunately, Calamity Ganon had learned how he was previously defeated and corrupted the Guardians and Divine Beasts with malice and turned them against Hyrule. But since Calamity Ganon is defeated by Link fighting him and Zelda sealing him away with her divine power, the plan does end up working more than once.
    • During the fight with Maz Koshia at the end of "The Champions' Ballad" DLC, Link can use some Mighty Bananas as a Delicious Distraction, though the boss will only fall for it once per fight.
  • In Marathon 2, Durandal gets frustrated by this trope. He has a clever plan to introduce a virus into Pfhor war machines and turn them against their masters. It works... for about twenty minutes, before the Pfhor render it ineffective. Turns out another alien race called the Nar had that same idea twenty years ago, and the Pfhor have set up countermeasures against such tactics.
  • In Mega Man X3, you have the ability to swap out with Zero. It can only be used once per stage and if he dies, you lose him for the rest of the game. He's also needed to get his saber near the end of the game.
  • Metal Gear:
  • In NieR: Automata, during the endgame, 9S buys some relief from the Logic Virus by hacking himself to fight it off. However since it adapts very quickly, it won't work the second time and when he becomes infected once more at the end, he takes on Red Eyes, Take Warning.
  • Paper Mario 64: To some degree, this happens in the first (non-hopeless) fight with Bowser; his invincibility can be canceled out with the Star Beam you've spent the entire game earning. In the second a short time later, the move is now useless and you must get one better to win.
  • In Persona 5, this applies to the Phantom Thieves, who force a change of heart onto a person by stealing the root of their distorted desires, their "Treasure", from that person's Mental World. To make the Treasure take physical form so that they can steal it, the Thieves have to send their target a Calling Card in the real world. The shock and paranoia from the warning are what make the Treasure manifest, but those emotions won't last long and the Thieves can't repeat the process; they only get one day to steal the Treasure.
  • Pokémon:
    • The Master Ball, which has a 100% chance of capturing any Pokémon, but you're only guaranteed a single one in each game, which becomes especially frustrating in later generations as the number of stupidly difficult-to-catch Pokémon increases. You can get more through the lottery in most games, but the default odds are 1 in 100,000.
    • There is an item called the Sacred Ash, which revives all fainted Pokémon in your party AND fully restores their HP. The catch is that it appears almost exclusively in the presence of wild Ho-Oh, so there's only one in the game. The Festival Plaza in Sun & Moon, however, lets you purchase it.
    • Technical Machines (TMs) were initially one-use items and often limited to one per-game, so you only had one opportunity to teach Blizzard to a Pokémon. Pokémon Black and White onwards, however, made them have infinite uses.
      • Some TMs were buyable in the first four generations, so the player technically could teach certain TM moves to multiple members of their party. However, the TMs could still only be used once apiece, so players would have to repeatedly buy them to do so.
      • Generation VIII mixes up the formula; TMs remain infinite in usage, but the moves that they teach are often on the weaker side. TRs (Technical Records), on the other hand, are single-use variants that generally teach much stronger moves.
      • TMs are back to being single-use in Generation IX, though players are now able to create more whenever they want as long as they have the materials for it.
    • There are a few moves like Overheat and Draco Meteor that, while very powerful, cut the user's Special Attack stat in half. Naturally, this means that it should wipe out whatever it attacks because the Pokémon will be effectively useless for the remainder of its time out of the ball. This can be remedied by recalling it, but as that's the obvious move, the opponent will be able to predict you doing that.
    • A more extreme version would be sacrificial moves which cause the user to faint. These range from support (such as the stat-lowering Memento and the healing Lunar Dance) to attacks (such as the high-power Explosion or the damage-equal-to-lost-HP Final Gambit).
    • The move Fake Out is a high priority attack that makes the target flinch 100% of the time, but it only works on the first turn the user is sent out.
      • The same goes for First Impression, a Bug-Type variant more than twice as powerful that was introduced in Generation VII.
    • Z-Moves are devastatingly powerful and always accurate, but can only be used once per battle. Not per Pokémon, but for the whole battle.
    • Mega Evolution and Dynamaxing are the same as Z-Moves: extremely powerful, but only one Pokémon can use it per battle. And while Mega Evolution lasts until the user faints, Dynamaxing only lasts for three turns at most and will be cancelled if the Dynamaxed Pokémon so much as switches out before the three turns elapse.
      • Terastalizing in Gen IX works like Mega Evolution; can only be done once per battle (after which the player must visit a Pokemon Center to recharge the ability), but it's active until the Pokemon faints.
    • Burn Up requires the user to be a Fire-type to use, and causes them to stop being Fire-type when used. The same thing goes for Double Shock, except for Electric-type Pokémon.
  • In Quest for Glory IV, the ultimate joke is this. Anyone who hears it will laugh, no matter how little a sense of humor they have, but only the first time. You use it to distract the Big Bad long enough for you to kill him.
  • In Resident Evil: Outbreak: File #2, you find an Explosive Leash control for the rampaging tyrant, which you can use to skip one fight with him. It doesn't kill him, though, and if you use it early he will return.
  • In Road 96, there are several methods for crossing the border at the end of a character's story. Regardless of whether the character succeeds or fails, a method can only be used once per playthrough after which it is unavailable for future characters. The sole exception is the Offshore Worker Exam, which can be done twice by using different abilities.
  • In Sheep, Dog 'n' Wolf, Ralph Wolf uses a magic flute to hypnotize Sam Sheepdog and lure him away from the flock of sheep. It works so well, it's available to use in the next level. However, it's revealed that it won't work anymore as Sam now has earplugs.
  • Silent Hill 3: The Seal of Metatron from the first game. Granted, Alessa knew how to use it (having been Dahlia's daughter and all), and she only sought to contain "God" and the Otherworld within her area. Alessa's next incarnation though she may be, Heather is ignorant on how it works; and it is reportedly "difficult to control," indeed making it "just a piece of junk"... in her hands. Presumably Vincent doesn't know either, seeing as he would've told her how to use it otherwise. Leonard was only appointed its guardian, expecting a member of "the order" to be The Chosen One to use it, so it's also doubtful that he knew how to use it. Claudia may or may not have known the required ritual, but denies its efficacy. Oh, well... at least Harry left Heather a little present.
  • In Star Ocean: The Second Story, Claude uses his phaser beam (which the planet's locals call a "sword of light") to dispose of a beast attacking Rena. When he gets to the second town, he uses the phaser to break down a door, and it promptly (and inconveniently) runs out of power, and can never be used again.
  • In Tales of Symphonia: Dawn of the New World, Emil's Mystic Arte Ain Soph Aur can be used on Richter the first time, but if you try using it again, he will counter it with a Mystic Arte of his own, magnifying its damage output and targeting your entire party.
  • Twisted Wonderland: Jade's unique magic cannot be used more than once on the same person.
  • The final boss of Undertale's Neutral Route empowers himself by absorbing the six human souls the monsters had collected by that point. As the battle progresses, you call for aid and the souls answer, rebelling against the one using them and eventually enabling you to win. This character also possesses a Ripple-Effect-Proof Memory of your gameplay, so on subsequent playthroughs, if you reach the Neutral route's final boss again he'll opt not to go through with it since he knows the souls will simply revolt against him again and the end result will be the same.
  • We Happy Few: When a person remembers the past and refuses to take their Joy for long enough, they become a "downer"; in other words, they're a perfectly normal person in a world gone insane. Joy no long has quite the same intoxicating effects for them as it once did. It wears off very quickly, and leaves the individual extremely depressed, hungry and thirsty.
  • In Wing Commander: Prophecy, the protagonists capture an alien plasma weapon capable of destroying a fleet with one shot, install it to their carrier and successfully use it to destroy an enemy blockade. They then determine it would be too dangerous to try recharging it for a second shot.
    • Humorously described by one of the characters as "Fire and Forget. We fired it once, now we can forget about ever using it again."
  • XCOM: Enemy Unknown
    • Rockets. Since the Heavy Class is carrying a light machine gun (the heaviest weapon in the game), he is already very burdened, so he can only carry one rocket, with no way to resupply during a battle. Well, technically, if he takes the right promotion perks, he can use two rockets and a special shredder rocket (which causes less damage but inflict a Damage-Increasing Debuff), still, with a maximum of three rockets, make them count.
    • All active items work similarly. The medikit gets one use (three with a Field Medic Support), four when he gets Deep Pocket in Enemy Within), grenades can only be used once (twice with the Grenadier Perk from the Heavy, or the Deep Pocket support ability in Enemy Within), the Arc Thrower can only be used twice (thrice with the Support ability Deep Pockets), the support Smoke Grenade can only be used once, twice with the Smoke And Mirrors ability (thrice in Enemy Within). It had to be noted it applies only during missions, as the squad gets resupplied for free between missions.
    • In XCOM: Enemy Within, there is a scripted event involving an alien attack on your base (if you lose this mission, it's Non-Standard Game Over for you). The means the Mind Control the aliens use on some of your techs to get them to sabotage your base defenses is stated to be a one-off.
  • XCOM 2: War of the Chosen: Each of the Chosen's bases can only be raided once, so you only have one chance to take each of the Chosen out permanently. If you fail to defeat the Chosen in their base, you will not get another chance, and that Chosen will continue to haunt you for the remainder of the campaign.
  • Yandere Simulator: Certain actions (mostly murder) you can only get away with once, because everyone will be on the alert the next time. Go on a masked murder spree? Masks are banned from school. Kill a student council president? The School Atmosphere will drop to its lowest (making everyone more watchful), and metal detectors and security cameras will be there to cause problems. Each rival also has a person-specific murder method, that you only get one chance at as they won't be in position at any other time (i.e. Kizana is killed at the play she's acting in).

    Visual Novels 
  • In Ace Academy, it turns out that the overdrive function of the main character's GEAR only activated once because it was a one-time debug mode feature. After finding this out, Valerie decides to program it so that the main character can activate it on demand.

    Web Animation 
  • RWBY:
    • Velvet Scarlatina's weapon is a camera named Anesidora. By taking a picture of a weapon, Anesidora can use the photo as a schematic to create a copy of the weapon from Hard Light Dust. Combined with her Photographic Memory Semblance, and Velvet is a phenomenal Ditto Fighter. Unfortunately, the weapon copies only last for a short amount of time before disintegrating and the picture used to make them is deleted as well.
    • When Ruby summons Jinn to exploit her Time Stands Still ability to buy time in battle instead of asking a question, Jinn admonishes Ruby's misuse. She warns Ruby that she'll never allow herself to be summoned again unless it's to ask for knowledge, but permitted it this one time because she thought it was clever.
    • In Volume 8, Oscar is able to employ an ability no-one knew he had to buy the heroes time against the Big Bad. However, he warns them afterwards that it was a one-shot power, and they won't be able to do that again. Ozpin spent many lifetimes storing kinetic energy in his cane. Oscar unleashes it as a Fantastic Nuke that takes out both Salem and most of her Grimm army, but without harming people and buildings. It buys them the few hours they need to evacuate the kingdom before Salem can regenerate, but at the cost of most of the cane's power.

    Webcomics 
  • The Adventures of Dr. McNinja:
    • In Chapter 3, Dan McNinja defeats Frans Rayner by punching him in the right butt cheek and exposing his neckbeard. Years later, when Dr. McNinja fights him, Frans has moved his weak spot to a different location and taken extreme precautions to keep his beard from ever being noticeable.
    • Also applies to holy weapons throughout the series: it's one banishment per weapon, and if the numbers suddenly change on you, you'd better have another trick up your sleeve.
  • In Cwen's Quest mysterious life slave Riddly Lancer defeats a huge dragon with an equally huge DBZ style blast. Next chapter when asked to do it again to defeat the next bad guy he simply reports he can't. Luckily he apparently has a few other skills.
  • Girl Genius: Downplayed — Gilgamesh's experimental lightning generator only destroys two Humongous Mechas before it melts, but because the equipment is hidden from view, the show of force is more than enough to make the rest of the attacking army surrender.
    Gilgamesh: This is not a trick! I did not get lucky! I am Gilgamesh Wulfenbach — and I am in control!
  • The Treasure Juju in Homestuck can only ever be used twice, but each use is so drastically different that they could technically be different items. The first time, it can only be used by Caliborn as a weapon against his enemies (by sealing them away inside it forever). The second time, it can only be used by Caliborn's enemies against him (by unleashing their power in one concentrated blast).
  • The Order of the Stick: Vaarsuvius tells Durkon that their brief period of unimaginable magical power was "a singular event" that can't be repeated and doesn't disagree when Durkon asks if it had a heavy Cast from Experience Points cost. It's true that it almost certainly can't be repeated... because the power came from a Deal with the Devil that the Fiends almost never grant, and comes with a debt that Vaarsuvius hadn't even started to pay off.
  • Schlock Mercenary
    • The comic had a Time Travel storyline; but the particular method could only work once due to some of the equipment being destroyed in the process (and before the effective start of the conditions that made it useable in that way), meaning only one shot...
    • And in Book 20: Ennesby is 'hiding' in the Pa'anuri's long gun software, and is asked to "jiggle their aim." In the midst of complaining that it would work just once, since the enemy would figure out what happened, he realizes he could jiggle the targeting data feed... to make the long gun fire on itself.

    Web Original 
  • In the Counter Monkey episode "The Bardic Knock Spell", Spoony discusses this in relation to RPGs, saying that if you can impress the Game Master, he'll let you get away with doing something really audacious, but he'll only give it to you once. The example he gives, the titular "spell", involves gaining access to the villains' stronghold by just knocking on the front door, then punching out whomever answers.
  • In Dream's "3 Hunters Finale" video (the third of the 3 Hunters series), Dream sets up an escape route leading to an End Crystal he intends to use to blow up the hunters (as their gear is too good for him to win in a straight-up fight) — and he succeeds. Two Manhunts later, in the "3 Hunters Grand Finale" video, Dream sets up an escape route leading to another End Crystal for the exact same purpose — but the hunters, knowing to be on-guard, realize they're in a trap quickly. Bad also spots the End Crystal when he's out of range, and the hunters are able to avoid the trap.
    • In the first "3 Hunters" video, Dream dies when the Hunters enter the End before he does, and trap the portal with lava. In the Grand Finale of the same series, a similar scenario happens where Dream is beaten to the portal by hunters who set up a trap in the End. However, Dream wised up and drinks a fire resistance potion before entering, and throws in an Alpha Strike of 12 TNTs set to explode just as they enter The End on top.
    • Typically, Dream only uses the various kinds of traps and trickery once. On the one hand, it's definitely more fun to see newer ways to outsmart the hunters, but on the other hand it's quite clear that some tricks just don't work twice.
  • An explicit theme of Fine Structure. Any given superscience technique will only work briefly before the Imprisoning God notices and changes the physical laws of the Universe to make it impossible.
  • In the Overwatch League 2018, Los Angeles Gladiators pull off the "Great Bamboozle" strategy by pretend to be a GOATS comp to trick the London Spitfire to engage while their defense wide open for Gladiator's sniper to pick off crucial DPS and support wins the first game. 9 hours later in Overwatch Contender, GC Busan Wave tries to replicate the Gladiator's strategy, but their enemy team Seven immediately predicted this and counter accordingly. Even the commentators sums up this plan only works once.
  • Draugr, from The Saints, like other undead, have specific weaknesses. Unlike other undead, the quickly adapt and overcome those weaknesses.
  • In the Supermarioglitchy4's Super Mario 64 Bloopers episode "Mario and the T-Pose Virus", the T-Pose Virus caused by Waluigi is undone by using 1-up Mushrooms. In "The Mario Convention", Waluigi creates another T-Pose Mushroom, which turns Meggy (and others) into T-Pose zombies. Mario tries using a 1-up Mushroom on Meggy, only for it to have no effect due to Waluigi becoming an Invincible Villain thanks to his Rejection Powers being stronger this time around. The only way it was eventually undone was because Waluigi's staff was destroyed during War of the Fat Italians 2018.
  • According to Things Mr. Welch Is No Longer Allowed to Do in an RPG, sending a stripper to the guard office follows this principle.
  • Whateley Universe: A few devices work like that. The Psi-grenade, cannot be recharged after it's been detonated and Mega-Death's Force Field Disruptor burns itself out after it's been used. But multiples of each can be made.
    • This is a semi-common trait of devisor items. They specifically cannot be replicated, because they depend upon the mutant's reality-warping power. So each individual black hole grenade is its own unique item. This has led to a kind of disconnect between Devisors and Gadgeteers. The former sells you an ultra-powerful weapon you can use precisely once. The latter sells you a slightly less powerful weapon you can actually reproduce.
  • Worm:
    • Leet has this as an explicit part of his superpower. He can invent a machine to fulfill any function... once. If he tries to make a second one, it just explodes in his face.
    • Crawler, a cape with an adaptive healing factor, becomes resistant and eventually immune to any form of damage he sustains and from which he regenerates.

    Western Animation 
  • On an episode of The Adventures of Jimmy Neutron, Boy Genius, the title character builds nanobots in a flying saucer to defend him from bullies. They malfunction and begin to threaten everyone who comes within 5 feet of him. He defeats them Logic Bomb style by beating himself up. Take 2: Jimmy re-hires the Nanobots as Beta Readers for his homework assignments, and they take their "correcting errors" to extremes, going so far as to start correcting human error (bad posture, fashion, etc.) He tries to Logic Bomb them again by saying that flaws indicate that humans are functioning perfectly, but they stop trying to puzzle it out, call it "extreme error" and just start deleting people off the face of the earth. Somewhat subverted, though, in that he still uses their programming to overload them; he purposefully miscalculates a number on his homework, and asks the nanobots to correct it. The number in question? Pi, which no computer could calculate to perfection.
  • In The Adventures of Puss in Boots, this is how all magical fountains work. You can only benefit from the effects of a fountain once, and if you say "release" to negate the effects, you don't get a second chance.
  • The Lich from Adventure Time is a master of this. If it's beaten him once, he'll make sure the heroes don't get a chance to use it again. First off by destroying Billy's Gauntlet before Finn can use it against him. Followed by swatting Finn away while possessing Princess Bubblegum before he can use his "Like-Like Sweater" to destroy him. And as of the Season 4 finale, killing Billy, the one who imprisoned him in amber. Notably, it's not because he gets stronger in-between attempts, he's just really good at planning and manipulation.
  • Both used and subverted in The Batman episode "Meltdown". Batman first defeats Clayface by throwing a freeze-bomb at him. When he tries it later, Clayface said he saw it coming and just made his body hard so it bounced off. Then Detective Yin does this after pretending she was going to shoot him which prompted the line:
    Clayface: Didn't expect that from you Yin. I guess you do have... a new partner.
  • Something similar happens in Batman Beyond. Inque was vulnerable to freezing and water in her first appearance, but in later appearances learned to curl herself into a ball, protecting the bulk of her mass from being frozen and breaking free in short order, or modifying her chemical makeup to resist water. Batman himself uses this against Inque, protecting himself from being enveloped by her with electricity based contact defenses.
  • Beast Wars;
    • The death of Maximal leader Optimus Primal in the first season finale was undone several episodes into season two with the justification that the nature of his death, destroying the Planet Killer device, left a direct energy trail from his spark to the matrix, the transformer afterlife. Even then, retrieving him was said to push Rhinox's mental capacities to their limit and they needed a blank protoform body to put Optimus's spark into once he was retrieved. It was all very lucky they were able to get him back, and most certainly wouldn't be able to be done twice.
    • Megatron's first attempt to attack a group of the early ancestors of humanity in a specific valley to prevent the evolution of modern man was never repeated, as Dinobot stopped the Predacons killing the early humans and then shattered the Voyager Disc that allowed Megatron to view his effects on the future. As the surviving proto-humans were forced to flee the valley in separate groups, the tribes were left scattered and in hiding, and with no access to the Disc's message, Megatron gave up on attempting to wipe out humanity as he could never be certain that he could find and kill enough of them to change the future to his specifications. He still had the proto-humans hunted on a few occasions, but only as part of other schemes.
  • In Ben 10: Ultimate Alien episode "Solitary Alignment", Ben questions why they can’t simply let George use Ascalon to defeat Dagon a second time. Azmuth explains that Dagon underestimated George the first time they fought and is unlikely to make the same mistake twice.
  • Subverted in Family Guy. Peter and Brian get rid of James Woods by leading him along with pieces of candy and trapping him in a crate. When he comes back later, he steals Peter's identity and they go through a long ordeal, but then Peter and Brian eventually get rid of him in the exact same way with Peter pointing out that they should have tried this again from the beginning.
    Peter: Okay, Brian, next time let's remember this right away because he's done this twice.
  • The Quantum Destabilizer gun from Gravity Falls zig-zags this trope. Dipper and Ford try to use this against Bill Cipher in Weirdmageddon Part 1. Ford directly acknowledges that they only have one shot, and while the shot does damage Bill, it fails to kill him. Ford is captured, and the weapon is never able to be used again.
  • A Gumby cartoon had Gumby returning a wand to a magician who left it behind at Gumby's lemonade stand. The magician rewards Gumby with a wand that will perform a single trick. Gumby uses it to repair his mother's pitcher that got broken at the start of the cartoon.
  • In an episode of Hot Wheels: Battle Force 5, the team needs to head to a nanotech stabilizer and can't afford to go through a Battle Zone first, so Saige reveals a crystal that lets them skip the Battle Zone and go straight to their destination. When asked why they don't always use such a crystal, she reveals that she only managed to obtain one, thus limiting its use.
  • Hulk and the Agents of S.M.A.S.H.: "Banner Day" has the Hulk willingly depower himself so he can go back to being Bruce Banner all the time. Naturally, this is when the Kree show up and demand Hulk turn himself over to them or they'll blow up Earth. Bruce re-exposes himself to Gamma, with Betty Ross telling him that due to the way it works, he'll never be able to use this method again. They still think it's Worth It.
  • Justice League:
  • In the Kim Possible episode "Queen Bebe", Kim encounters the Bebe robots she had faced in "Attack of the Killer Bebes", which she managed to defeat by disabling them with a high-pitched frequency. Unfortunately, when she tries to use it again, she finds that it has no affect.
  • Looney Tunes:
    • A straightforward example would be the Bugs Bunny / Daffy Duck cartoon "Show Biz Bugs" in which he is trying to go one-up on Bugs in their stage act. When none of his tricks impress the audience, he desperately tries his ultimate trick: downing several kinds of volatile explosives and then swallowing a lit match ("Girls...better hold onto your boyfriends!"). It works so well that everyone, including Bugs, are impressed, and call for more. There is just one problem: Daffy is dead and his ghost says he could only do it once. The trope title is obviously the punchline to this gag. The same gag was also used in "Curtain Razor" with a wolf trying to impress Porky Pig (who is a talent impresario in this short) with his act. In the end, the wolf gets his chance after several attempts, then doing the trick aforementioned, and as expected, the same punchline (kinda) is delivered.
    • In the short "The Unmentionables", after agent Elegant Mess (Bugs) blasts Rocky and Mugsy with a loaded carrot and it empties, he quips "That's the trouble with carrots. They're only good once."
  • John Dread from Max Steel pulls this one on Max. The first time around when Max tricked Dread into punching his claw into magma it was quickly melted off and he was defeated. The second time it happens, Dread lampshades that he fell for the same trick twice, but this time around his claw is made of an alloy that won't melt at that temperature. Cue Oh, Crap! face from Max as he's now facing Dread with a red hot glowing claw.
    Dread: Same old trick. Too bad it's not the same old claw.
  • My Little Pony: Friendship Is Magic:
    • The Elements of Harmony against Discord. This time they're dangling the elements over his head as leverage to force him to play along while they try and reform him, but the first two things Discord does is destroy all of Twilight Sparkle's "reform spells" and sweet-talk Fluttershy into promising to never use her element against him, rendering the rest completely useless. Of course, he ends up pulling a legitimate Heel–Face Turn, so it's rendered moot.
    • Word of God is that this is why Celestia never used the Elements in the show. She and Luna originally used them to seal Discord, but then Luna turned into Nightmare Moon. Even Celestia wasn't powerful enough to use the Elements on her own, so she had to use a spell to be able to wield them by herself against Nightmare Moon — but the cost was that she'd never be able to use the Elements again.
  • The Powerpuff Girls (1998):
    • Mojo Jojo tries to avert this in one episode by trying an old plan a second time, thinking he's taken precautions against what ruined the plan the first time. The girls defeat him anyway, showing that maybe it's best to turn your back on plans that have already failed once after all. Considering that his precaution was to not turn the girls into dogs, thus preventing them from biting his butt (now protected by a metal plate, one would think that doing either of those things cancels out the usefulness of doing the other, but whatever) and making him break the magic idol he was using, they weren't very good precautions. He forgot that, since the girls aren't transformed, they can foil his plans in the same way they foil all his plans; by beating him up.
    • In the episode "The Boys Are Back In Town", when the Rowdy Ruff Boys are brought back by Him, the girls try to defeat them the same way they did before, with cootie-filled kisses. Unfortunately, thanks to Him, they were now immune to cooties. Even worse, they ended up becoming giants instead of exploding.
  • In Samurai Jack, Aku manages to fool Jack by transforming into a beautiful woman named Ikra and feeding him a sob story to gain his trust, which results in Aku trashing a portal to the past and taunting Jack about it. The second time Aku tries this trick, however (this time as a Yoda-ish old master), Jack immediately sees through it: he Bluffs The Imposter, turns the plan against Aku, and nearly takes him out once and for all.
  • Scooby-Doo and Guess Who?: Invoked in "The Hot Dog Dog!". Big Eddy Eats admits he cheated his way into winning the previous year's hot dog eating competition by giving Joey Chestnut a basket of muffins so Chestnut would be too stuffed to eat hot dogs and says he used the monster costume this time because nobody would fall for the muffin trick twice.
  • The Simpsons:
    • Subverted when the family try to get Maggie out of a locked bathroom. Homer tries a coat hanger then gives up. Lisa tries it again and successfully unlocks the door.
    • Played straight in a Treehouse of Horror parody of Death Note, where one of the rules is that you can't use the same kill more than once. This forces Lisa to be more contrived in her kills, such as parachute accidents, toilet alligators and eventually toilet lions.
  • The Spectacular Spider-Man: In the Villain Team-Up episode, Doc Ock explicitly points out that none of the methods Spider-Man used to stop his foes last time will work: Doc Ock's arms are powered by Electro, the power pack on Vulture's back is better armored, Electro has much better control of his power (such that he can safely contact water), Shocker and Rhino know better than to confront him in an enclosed space, and um...there aren't any concrete mixers around to trap Sand-Man. It goes both ways, though, since Spidey's also been upgraded since the last time he fought them.
  • SpongeBob SquarePants:
    • One episode has a very picky customer named Bubble Bass invoke an Achilles in His Tent by making SpongeBob doubt his skills as a fry cook by claiming he forgot the pickles. When SpongeBob returns and confronts Bubble Bass again, he pulls the same trick, but SpongeBob quickly realizes how he got away with it when he starts laughing.
    • Another episode has a giant clam snatch Mr. Krabs' millionth dollar, with Mr. Krabs sobbing until SpongeBob and Squidward decide to help him get it back. After trying to fool him with a different dollar, Mr. Krabs starts sobbing again, only for Squidward to say that it won't work again (Mr. Krabs decides to resort to more drastic measures instead).
  • Star Trek: Lower Decks:
    • During a rigged training simulation, Boimler manages to somehow teach the Borg Queen empathy. However, rather than be allowed to walk away with his nigh-perfect score he's told to keep the simulation going. As a result, the Borg manage to adapt to this, and capture Boimler.
    • Bombs only work once, right? No one needs to make a point of that, because it's obvious. Unless you're Captan Dorg supplying munitions to the infamously stupid Pakleds. His frustration is abundantly clear when the Pakled captain tells him the veruvian bomb he gave them "stopped working" after they tried to test it on an asteroid to see if it would work. Well, it did. And as a bonus, the unique radiation it produces attracts two Federation ships to their location, exposing Dorg's conspiracy to destabilize the quadrant.
      Dorg: IT WAS A BOMB! YOU CAN ONLY USE IT ONCE!
  • When Spinel arrives on earth during Steven Universe: The Movie, she completely trounces the Crystal Gems with her confusing fighting style and unique Rubber Man abilities. When the Gems recover from their Spinel-inflicted Laser-Guided Amnesia however and shake 2 years of fight rust off, her tricks fail to fool them again, and she can barely land a punch.
  • Superman: The Animated Series saw the Man of Steel use this trope frequently. When his foes escaped from Cardboard Prison, they'd usually find Superman wearing a suit designed to be proof against their powers. Somewhat subverted, though, in that these suits were not foolproof and the villains found ways around them (or just ripped them off).
  • Teen Titans (2003):
    • In "Divide and Conquer", when Cinderblock puts Starfire in a bearhug, she knocks him back by kicking him in the face. In "Aftershock Part 1", this scenario happens again, but this time, he blocks her kick.
    • In "Titans East Part 2", Cyborg is the only Titan left who can resist Brother Blood's Mind Control. Blood has effortlessly torn Cyborg's limbs off, paralyzed the other Titans, and is ripping Cyborg's circuitry apart, trying to find the component that makes Cyborg immune. Cyborg announces "It's my SPIRIT!", instantly rebuilds himself, ignores Blood's energy blasts (the ones that blew his limbs off 15 seconds ago) and takes Blood out with one punch. They at least lampshade it this time.
      Beast Boy: So are you, like, magic now?
      Cyborg: Pretty sure that was a one-time deal. Blood was trying so hard to hack into my brain, I guess I sorta hacked into his.
  • In Titan Maximum, Palmer believes that his favorite move, the Sucker Punch, works every time. However his brother Billy points out that attack can only work once in each fight because it is quite impossible to catch the guy off guard again.
  • The Kairosect from Trollhunters is an artifact that allows its user to step outside of time, and while it actually only works three times, Blinky wastes the first two uses demonstrating it.
  • Winx Club: The final Gift of Destiny, the black gift, which can resurrect the dead, can only be used once.

    Real Life 
  • Early firearms (prior to the mid-18th century or so) worked like this in ground battles. Sure, you could reload them... but it took so darned long (1-3 minutes) and the ranges of the weapons were so short (50-100 yards) that you'd be lucky to get off two (somewhat inaccurate) shots in the time it took for an enemy (on foot) to come within range, charge and attack you with something sharp and/or pointy. Bayonets were developed so that muskets could double as melee weapons, eliminating the need for pikemen. Contemporary hand grenades (thus Grenadier units) and rockets — like those used in China — only work once.
    • Still musketeers and other gunmen usually carried somewhere between 8 and 16 reloads on their person (their flasks with gunpowder were known as "12 apostles", despite there not always being 12 of them). On top of this, there would be carts with more powder and bullets behind the lines. While some generals really liked charging to within range, having to run through the salvos of bullets usually meant the charging formation was in worse shape than the one being attacked by the time they arrived, and stood a big chance of losing the subsequent "push of pike". So it was more common to try and destabilize the enemy formation by firing at them yourselves and by sending loose skirmishers, cavalry charges and cannon fire at them, before actually going in for the melee. So most of the time, this trope was averted. There is a reason these firearms were used. Still, a rush could succeed if performed so fast that the enemy had no time to get ready for the hand to hand. This tactic saw a short period in the limelight after the invention of the plug bayonet, which had to be plugged into the barrel of the gun, and could therefore not be mounted before going into battle.
    • Teamwork allowed it to be averted. The Spanish, for example, developed a formation called the tercio, while in pike and shot warfare the pikes were there to hold the enemy just outside pike range while the muskets were used nearly at point-blank range. The shooters would fire then countermarch, allowing them to reload while fresh shooters were brought forward to take their shot. The pikemen and swordsmen were there to cover the shooters and fix the enemy at point-blank range so the gunners could destroy them.
  • The Liberator handgun. It was possible to reload them, it just took a long time. They were nearly useless as weapons, the lack of rifling meant that the bullets would sometimes strike sideways and bounce off of people if fired from more than a few feet away. The were good for super-short range kills, though — if the attacker could get within a couple feet they could be effective. The general idea was to use it to take out an occupying soldier and take his gun, which would invariably be bigger, hold more bullets, and in general be more effective than a Liberator. And more importantly from the Allied perspective, to demoralize the enemy with the fact that they had no idea just how many were out there, and how many of the seemingly helpless civilians in conquered nations were actually armed and just waiting for a chance to cap them.
    • The same applies to The Vietnam War-era replacement, the Deer gun, though its effectiveness as a weapon was never determined; when the war escalated, plans to hand the gun out to civilians in the same manner as the Liberator were abandoned.
    • The "Punch Gun", made famous in Inglourious Basterds, is a real gun that only works once in concept. Because you have to hit your opponent to "pull" the trigger, it would be hard to not kill him. But if he has buddies around, you will be in for a rough time.
  • The tactics the 9/11 hijackers used to seize control of the planes fall into this category, even if you're not counting increased paranoia around airports making it unlikely that any repeat performances would even make it to the plane (several of the hijackers had been flagged as suspicious, but lax security meant they got through anyway).
    • Generally speaking, since most passengers in previously hijacked airliners did in fact survive, there was no reason for passengers and crew not to cooperate.note  Now that using the plane as a kamikaze weapon has been firmly established as a possibility, trying to take over a plane with knives will likely not work because the passengers and crew will fight back and overpower the hijackers. In fact it is a commonly cited theory that the passengers of United Flight 93 knew what had happened to the other flights hijacked that day and either risked their lives because they had nothing left to lose or went on an outright suicide mission to subvert the attackers.
    • Secondly there are standing orders that the cockpit will rarely be opened during the flight and never during an attempted hijacking. Even if the cockpit is open someone will be posted on guard to prevent access.
    • Finally military pilots are trained to shoot down commercial aircraft if necessary and will do so if they consider the plane will probably be used as a missile against a strategic target.
  • The M72 Light Anti-tank Weapon, its modern successor the AT-4 and various similar designs based on the same concept play the trope both ways, as they have the reverse effect in practice; instead of having a dedicated RPG fireteam, who have to spend quite a long time reloading after taking a shot and can't carry very else besides the launch tube and its ammunition, every man in the squad can carry a one-use launcher as part of their regular gear. If one of them misses, another steps up and takes their own shot.
  • Successful suicide bombing. Likewise, if you botch the bombing such that you don't die but the target knows your intentions, they'll likely try their damnedest to kill you.
  • The Trojan Horse gambit — anyone with even the most cursory knowledge of military history will know better than to fall for it. It even spawned the phrase "beware Greeks bearing gifts".
  • One of the poetic metaphors for a woman's maidenhood (or, more generally, virginity) is "the rose that can be given only once". Considering what we know now about the hymen (i.e. it can regrow or even not break during intercourse), this is not necessarily the case, but it remains a truism.
  • Medical examples:
    • The arsenical medicine melarsoprol, used against African sleeping sickness, is extremely toxic. So toxic, in fact, that it can't be administered to someone who's already been dosed with it.
    • The precordial thump is a sharp punch to the sternum sometimes attempted during CPR, as a form of mechanical defibrillation in the event you don't have an AED. In real life, it's never done more than once. The thump has to be performed within 60 seconds of the onset of symptoms, making it useless in all but immediately witnessed arrest. In fact, according to one study, all reported successes have been within ten seconds! Basic CPR training no longer includes it at all, and Advanced Cardiac Life Support only mentions it in passing.
    • Cats do not have antibodies for dog blood cells, so if no feline blood is available, an injured cat can receive canine blood instead. However, within four days the cat will have developed said antibodies and can never receive dog blood again without suffering a severe (likely fatal) reaction.
    • Some diseases only affect each person once, since the next time they get infected the body already knows how to deal with the problem. In fact, this is the idea behind vaccines: get infected with a harmless version of a microbe so your body is ready when you have to face the real one. But this also works the other way, since some diseases evolve too quickly for immunity to last very long. This is why new flu shots are issued each year to keep up with new strains.
  • Ceramic trauma plates for body armor can work this way. When struck with significant energy (by a bullet, hammer, fragment, splinter or by being dropped), it will crack and the effectiveness of the plate degrades, but isn't automatically rendered useless. However, a second hit in the same general area will typically go through, making this trope true for hits in the same location. With luck, subsequent hits will be far enough away from the damaged areas to be stopped as well. This won't work forever, but has been seen in the field.note  Though heavier, the ballistic value of ceramic plates is generally much higher than traditional metal trauma plates.
    • This is also the case behind Explosive Reactive Armor (ERA) for tanks and armored personnel vehicles. When touched by an EFP (Explosively-Formed Projectile, the most common form of anti-armor round in use today, which essentially is a bolt of molten metal), the ERA plate explodes, disrupting the jet and preventing it from penetrating the vehicle's armor. Once an ERA plate detonates, that section is unprotected from further hits until it is replaced. While it's very hard to hit the same spot twice, especially from far away, it's not impossible. ERA-protected vehicles have been destroyed by such unlucky double strikes. Newer armor-defeat munitions actually stack multiple shape-charge warheads that fire in sequence, burning through ERA and armor and allowing the hindmost EFP to penetrate to do damage.
  • Occasionally, video game developers will give out game copies or extra content to dedicated fans with emphasis on the fact that they're rewarding their passion or ingenuity, so anyone trying to do the same thing with the expectation of a prize can't piggyback off someone else's ideas or effort.
    • Before the release of Fallout 4, an excited fan sent Bethesda a box of real-life bottle caps weighing over 11 pounds with a tongue-in-cheek letter asking Bethesda if this would be an acceptable substitute for payment (bottle caps being currency in the Fallout universe). To his surprise, Bethesda then sent him an email accepting the "payment", and agreeing to send him a copy with the understanding that they were not opening the door for any copycats to try and pay for the game in a similar way.
    • Similarly, Psyonix gave one dedicated player a special "Pigeon Man" tag for collecting one thousand pigeon head toppers in Rocket League. However, they made clear that they would not give the tag out to anyone else for collecting any number of pigeon head toppers, nor would they make tags for any other player who collected a bunch of any in-game item.
  • A "zero-day" vulnerability is a computer security hole that is not yet generally known, named for the fact that nobody has had time to develop defenses "zero days" after someone discovers and exploits the vulnerability. Once a zero-day exploit is used and noticed, cybersecurity experts will study it and develop countermeasures to be distributed in future security patches.
  • In Sports, particularly American Football, trick plays tend to fall in one of three categories: Either they're so ingenious, they become part of the game, or they work based on being illogical and not what the opponent would expect (in which case they will remain rare and often only used in desperate situations) and the third category are those that make use of Loophole Abuse, in which case there is likely to be an Obvious Rule Patch right after it's been used the first time. The first category is often not even considered a "trick" any more and includes stuff like play action passes, the second includes stuff like fake punts and the third includes stuff that is usually subject to quite a bit of controversy afterwards.
    • The "Holy Roller" was a controversial play in a 1978 Raiders v Chargers football game where the Raiders' quarterback, upon being tackled, "fumbled" the ball up the field towards the end zone. Another player then also tried to grab it, "fumbling" it as well to a third player, who "struggled" to get ahold of the ball until it was in the end-zone, at which point they fell on it for a touchdown. After the play, the rules were changed so that forward fumbles could not be recovered by the offense for a gain, and years later, the players involved admitted that they had deliberately fumbled the ball forward, which would have made the whole play illegal even under the rules at the time.
    • In 2015, the Patriots ran a trick play against the Ravens in a playoff game which relied on confusing the Ravens about which players were eligible receivers. Per the rules at the time, the offense was required to inform the referee which of their linesmen were eligible or ineligible receivers, and the referee was required to inform the defending team that one of the linesmen was an ineligible receiver. However, more information wasn't required, making it unclear to the Ravens who exactly was and was not an eligible receiver, making it much harder for the Ravens to defend against passing plays. After the game, new requirements were put in place for identifying ineligible receivers at a glance based on where they lined up.
  • One of the problems at dealing with the Roman Army was that they learned from their defeats, and the next battle they were liable to show up with a counter or even having adapted the enemy gamebreaker for their own purposes:
    • Possibly the earliest example is their uncanny ability to trounce war chariots. They first met them at the Allia river, where the Senone Gauls used theirs (small and only able to carry one man) to surprise and crush a portion of the Roman army deployed on a hill, sending the rest in panic and achieving such a victory the Senones thought it was a ruse; when the Romans faced again the Gauls in open field at Pedum their troops carried caltrops precisely to deal with the Gaulish charioteers by wounding their horses, and even mimicked the deployment at the Allia river just so they could lure them in and deal with the Gauls' best troops early. After that engagement the Gauls on the continent quickly abandoned the use of chariots, and the Romans would only meet war chariots when invading Britannia (whose inhabitants had never faced caltrops before and so had not abandoned their chariots) and when expanding in the Middle East, whose powers had maintained the use of large chariots with archers and Spiked Wheels until the Romans started deploying caltrops - and then coming up with other methods because to them dealing with war chariots had become a game.
    • Another example, where they countered one enemy gamebreaker and hijacked the other, is how the three battles fought against the Epirote army led by Pyrrhus went: at Heraclea the Romans were easily matching the Epirotes and even started gaining the upper hand after overcoming the enemy cavalry, only to be routed when Pyrrhus sent his War Elephants in, a beast the Romans had never met; at Asculum the Romans showed up with anti-elephant wagons, contraptions equipped with large polearms, fire-bearing grapnels, and all sort of projectile weapons, and while they were defeated they retreated in good order after killing many irreplaceable veterans and even sacking and destroying the Epirote camp (in particular stealing their famed molossoid dogs), prompting Pyrrhus to quip "If we are victorious in one more battle with the Romans, we shall be utterly ruined"; and at Maleventum the Romans, after repulsing a night attack thanks to guard dogs bred from the ones stolen at Asculum, answered the elephant charge with enough projectiles aimed to their weak trunks that they killed two, captured eight, and routed the rest through the enemy army.
  • Muhammad Ali had a coin trick that he would sometimes perform to people. However, after doing so, he would show them how it's done, because Muslims don't believe in deception. As a result, said coin trick won't work a second time for those people.


 
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Alternative Title(s): Only Works Once

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Sonic the Hedgehog 2006

When Shadow attempts to put Mephiles back into the Spectre of Darkness just as he did 10 years ago, Mephiles manages to escape and can no longer be trapped in there.

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Main / ItOnlyWorksOnce

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