Hour of Power

"Because of Earth's polluted atmosphere, Ultraman can only retain his gigantic form for three minutes. Time is running out."

— The narrator, every episode of Ultraman: Towards the Future

Superpowers can be loosely broken down into those that are "on" all the time such as Superman's super-strength, and those that need to be activated in some way by the character such as Superman's heat vision.

Hour of Power, named for the Might and Magic spell, is a special limitation placed on the latter type, in which the power only lasts for a certain time interval after being activated. This time interval is always the same, no matter how many times a character activates it, and it's always an easy-to-remember amount of time, usually a round hour, but occasionally a number with some other significance. Expect lots of Race Against the Clock plots, where the character comes perilously close to running out of time while in the midst of danger.

There's usually no explanation of why the limit exists, or why it's so specific. If it's magically imposed, it's not a big problem, since magic only needs to be internally consistent. It's a little more egregious when the powers are granted by Applied Phlebotinum, especially if every other time limit has been broken, or if it's clear that the creators don't use "Earth" hours. Real Life technology doesn't tend to have fully predictable running times, but fictional technology, apparently, has it all the time.

Most of the time though, it is just useful for writers to create a sense of danger. The character is forced to be careful about how often to use their powers, and can be put in opposition to a sufficiently prepared villain. This is one way to avoid the Sorting Algorithm of Evil.

Compare Fuel Meter of Power, which puts a similar restriction on powers but can't be recharged. Also see Super Mode.

Not to be confused with Pastor Robert Schuller's broadcast from the Crystal Cathedral.

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Examples:

Anime & Manga

• Ayakashi Triangle: On top of being An Ice Person, Snegurochka can give one person a day whatever they most want at the moment, imitating her grandfather Ded Moroz. The gift can seemingly be anything (even abstract desires, like personal fortitude), but disappears after a few hours at most, which is compared to melting snow.
• More like 10 seconds of power, but Asta in Black Clover has learned how to draw out the anti-magic properties of his sword and enhance/enshroud his body with that energy. Unfortunately, he has very little control over it and he can't sustain it for long periods of time otherwise it would make him. Over time he trains to gain better control over it and last longer in this form.
• Bleach:
  • All the Visoreds have time limits for their masks. Two are confirmed to be able to hold it for three minutes although it's implied this is the approximate time limit for all the Visoreds with the exception of Mashiro who can hold her mask for 15 hours and for unknown reasons has always been able to do so. They trained Ichigo to be able to hold his mask for 11 seconds. Protecting Orihime and Nel from Grimmjow is what allowed Ichigo to break the 11 second barrier and develop the ability to use the mask indefinitely. And to immediately regenerate the mask when it breaks. He's the only Visored who was capable of out-growing this trope. This is because Ichigo got his Hollow powers in a different way. He's not a Shinigami who was later infected with Hollow powers, but a Shinigami who was born with them.
    • Rose says the reason that he and Love can only keep their masks on for three minutes is because they're superheroes.
  • Prior to the time-skip, Hitsugaya's Bankai Daiguren Hyorinmaru could only be maintained for a set period of time before dissipating. His Bankai activated with three four-petal ice-flowers that hovered behind him. As time passed, the petals disintegrated, one at a time like a clock ticking down. When the last petal shattered, his Bankai disappeared. This was explained as his power being youthful and immature so he wasn't fighting with a completed Bankai.
    • Downplayed, the petals only appear when there is no water in the area. If there is water, the Bankai can repair itself. And following the 18 month timeskip, he's mastered his Bankai sufficiently that the time limit never applies anymore.
  • Yhwach can only leave his territory for an unspecified amount of time and is forced to retreat when Aizen slightly messed with his perception of time to make him think he had more time left. Energy seems to start bleeding off him when he hits the limit. He later gets around this restriction by transporting everybody into his realm.
• In A Certain Magical Index, Accelerator gains this limitation after his Heel–Face Turn. Originally, he could use his Story-Breaker Power to change physical vectors as often as he wanted, with no real limitations. Later, however, he can only use it for up to thirty minutes, and relies on a vulnerable transmitter to do it. He later manages to improve the device and make it more energy efficient.
  • The powerful mage Cendrillon automatically loses her powers at midnight or sunrise, similar to her namesake: Cinderella. Unfortunately for her, she will also lose her powers if midnight or sunrise is simulated.
• Digimon Universe: App Monsters: The heroes' Appmons can only stay on their Ultimate-level forms for 60 seconds. This restriction gets lifted eventually when the transformation devices are upgraded and their capacity increases.
• Cure Ace of Doki Doki Pretty Cure can only stay transformed for no more than 300 seconds. She's also the only Cure from the franchise who transforms from a kid into a late teen/adult.
• Numerous examples in Dragon Ball and its various sequels/movies.
  • Oolong has shapeshifting powers that only work for five minutes before he changes to his default form. This is because he was kicked out of shapeshifting school before he could learn how to shift indefinitely.
  • Freeza's Full Power form is a beefed up version of his final form, but since Freeza almost never uses the form, he has zero stamina and burns out all his energy in less than five minutes. In Dragon Ball Z: Resurrection 'F', his new Golden form has the exact same problem, ironically after he had supposedly learned his lesson from his previous failure. When he's resurrected again for the Tournament of Power in Super, he has much better control of the form, having spent his time in the underworld meditating and visualising countless ways to murder Goku.
  • The Fusion Dance introduced in the Buu arc allows two characters to fuse into a composite being with the powers of both, but only for thirty minutes before the technique ends and they split apart. If the beings are particularly powerful, it shorts out even sooner. In GT, for example, the fusion of Super Saiyan 4 Goku and Vegeta, Gogeta, is so immensely powerful that he defuses after only ten minutes.
  • The dead can be given permission to return to the world of the living, but only for a day. Like fusion above, a powerful character like Goku has even less time if he engages in prolonged fighting. What should have been a day was half that because used up all his energy fighting as a Super Saiyan 3, forcing him to return early.
  • Speaking of which, when he's alive Goku's Super Saiyan 3 form sorta falls under this trope. Unlike the SSJ1 and SSJ2 forms, SSJ3 burns through Goku's energy reserves at a considerable rate, and eventually his power level starts dropping if he stays in it for too long. It gives him an absolutely massive power boost, but it's mainly meant to quickly overpower and dispatch foes that are stronger than SSJ2, but markedly weaker than SSJ3, before his energy reserves have enough time to dip too low. If SSJ3 Goku is in a fight against someone close to his power, and they end up lasting long enough against him for that to happen (such as his fight against Kid Buu), he can end up in serious trouble. However, it's hinted that this limitation happened because Goku wasn't used to having a living body after being dead for seven years, which wasn't as durable and didn't have endless energy like his dead body.
  • The Super Saiyan God form in Dragon Ball Z: Battle of Gods turns a regular Saiyan into a God, but only for a few minutes. However, in Dragon Ball Z: Resurrection 'F', the Super Saiyajin God Super Saiyan (later renamed to Super Saiyan Blue) transformation appears to be a hybrized version of the God and normal Super Saiyan forms that does not share that weakness... but Goku's Super Saiyan Blue Kaioken form brings this weakness back, due to the immense concentration required to maintain Blue and Kaioken at the same time combined with Kaioken's naturally fatalistic properties that comes with over-reliance.
  • Dragon Ball Super Revisions the Potara earrings into having an hour-long time limit, declaring that it's only permanent for the Supreme Kais. Much like the Fusion Dance, excessive power can speed the clock up even further, which is why Super Saiyan Blue Vegito lasts less than an episode.
• The Japanese anime version of Teenage Mutant Ninja Turtles has the title turtles able to transform into super versions of themselves, but only for three minutes.
• Frag Time has Misuzu's ability to stop time for three minutes per day. She mainly uses it to escape from awkward social situations and otherwise mildy amuse herself. Over time, her time limit begins to decay, eventually leading to her losing the power altogether.
• In Freezing, the girls' superpowered, armored "Pandora" mode has a limit of three minutes, after which they can no longer fight for quite some time, meaning that this is a last resort only.
• Ban Mido of Get Backers can cause a person to hallucinate for exactly one minute (real time). He nearly always greets a person coming out of a hallucination with, "Exactly one minute. Have any bad dreams?"
• Ryuko Matoi's Kamui Senketsu in Kill la Kill initially has this limitation. Due to continuously feeding on her blood, extended use involves the risk of her passing out for blood loss. However, this issue is solved once both realize her embarrassment and rejection of Senketsu's skimpy gear was the problem. Once she accepts Senketsu, the issue is resolved. On the other hand, it's hinted that Satsuki's Junketsu has an unspecified time limit — after a prolonged battle, it begins attacking and has to be tranquilized for safe removal.
• Mobile Suit Gundam 00 has the TransAm system which, when activated, makes the Gundams turn red and go three times faster for a limited time. Afterwards, they operate at reduced power for some time (since TransAm releases all the stored power at once and it takes a while to build the stores back up). It's worse for the false GN Drive mecha in the second season, since they lack the power output and using TransAm shuts it down completely afterwards.
  • The main problem was TransAm couldn't be manually shut off in season 1, which meant they had to run it for the whole time limit even if they didn't need it and had to deal with the power drain afterwards. The system is later improved in season 2 to the point where it could be shut off at any point during the time limit to keep the output stable, allowing the pilots to only use it for a quick burst of speed or stronger attack and then shut it off without much of a power drain afterwards.
• In Mobile Suit Gundam SEED and Mobile Suit Gundam SEED Destiny, mobile suits run on batteries, thus they can only be on the field for a short time. This problem is made worse when beam weaponry and Phase Shift Armor is brought into play. Since only a handful of suits utilize the more destructive-but-lasting N-Jammer Canceller and Hyper-Deuterion Engine, other means have been used to keep Mobile Suits in play, including extra batteries, power extenders and new variations of the Phase Shift Armor.
• The Newtype-Destroyer (NT-D) Mode in Mobile Suit Gundam Unicorn last for 5 minutes when activated to prevent the pliot from getting overwhelmed, but is enough to curb stomp every mobile suit in sight.
• Moldiver is a rare example of a time limit that isn't a round hour, or even a round minute. It's still meaningful, though: 666 seconds.
• In My Hero Academia, All Might can only tap into his powers for a few hours due to an injury he sustained long ago, a secret known only by the main character and a few trusted comrades. When unpowered, he goes from a towering wall of muscle to an emaciated skeletal figure constantly coughing up blood. After passing on his Quirk to Midoriya, his time limit gradually gets shorter and shorter. All Might knows it won't be long before his power vanishes for good.
  • There are a few instances that show that All Might is able to tap into One For All past his normal limits. However, both times ultimately shorten the amount of time he can use it without straining himself even further, and the first time even has him coughing up blood in his All Might form.
  • Several students' powers also have set time limits. Kirishima can't maintain his hardening indefinitely, and he can only use Unbreakable mode for about 30 seconds. The strength boost Rikido Satou gets by eating sugar only lasts for 3 minutes, and Neito Monoma can only use the powers he copies for 5 minutes.
• In Naruto, Danzo has multiple stolen Sharingans embedded in his left arm. Using a technique called "Izanagi", he had 60 seconds of being completely unkillable for each eye he had, and he had 10 extra eyes, so this extended to a total of 10 minutes. He was ultimately beaten by getting his perception of time slowed down by a second.
  • In truth, this battle strategy wasn't as practical as it was convenient. With most fights in the series being chaotic brawls, anything could have happened to cause Danzo to lose track of the time he had for each eye, and he had to keep checking the eyes like a watch in the middle of his fight with one of the most dangerous ninjas in the series. Sasuke took advantage of this by casting a minor genjutsu to make him think he had more time than he actually did, thus he ended up taking a fatal blow in a Mutual Kill after he used up all his eyes when he thought he still had one left (Sasuke had another method of healing to take care of his own injury).
  • Sage Mode uses up a lot of energy and can only be recharged by standing perfectly still, so it wears off quickly in battle. Naruto gets around this restriction by using his shadow clones to recharge for him.
    • This seemed to be more because Naruto's jutsu took a considerable amount of chakra to use: At one point he thought to himself about having enough "nature chakra" for another Rasenshuriken, having already used one to destroy one of the Six Paths or Pain, after crushing another with a Rasengan, crushing summons with giant Rasengans, and another path with a dual Rasengan. In total, it's implied he only had enough to use the Rasenshuriken four times.
    • Later on, he manages to greatly surpass this limitation by throwing 5 Rasenshurikens in rapid succession before collapsing, and in another instance he creates a Rasenshuriken several times his size with the destructive power of a Bijuu-dama and still has enough sage chakra to fight.
  • Naruto's full-on Bijuu Mode only allows him 10 minutes at most to fight before it dissipates. This is because Naruto hasn't perfected it compared to Bee, who can stay in his Bijuu Mode for almost an entire day. After receiving Hagoromo's power, he can maintain an upgraded version of this form indefinitely and put out near-unlimited amounts of chakra.
  • Tobi's/Obito's Kamui technique makes him intangible for only about 5 minutes, which is a weakness that Konan exploited by bombarding him with continuous explosions for 10 minutes. He only survives by utilizing his own version of Izanagi with a spare Sharingan eye, a "perfected" version over Danzo's that lasts several minutes longer to outlast the remaining time.
  • The deceased Obito transfers his spirit into Kakashi to give the latter his full Sharingan abilities, but it can only be maintained for a limited amount of time before having to return to the other world.
  • One filler arc had a villain use a potion that gave him a transformation similar to the effects of Orochimaru's curse seals. Immediately after being defeated, he shrivels up into a powerless mummy-like form because the potion recipe was actually unfinished and had the side effect of burning up all his body's strength, leaving him permanently disabled.
• The Evas in Neon Genesis Evangelion technically have exact-time battery limits depending on power usage, but are usually conveniently vague about said usage. Evas can fight much longer while still attached to an umbilical power cord, but they're less agile and much less cool-looking when doing so. This is a deliberately-engineered safety precaution: if an EVA Unit were to slip its controls and rampage, NERV staff could cut its cord and recapture it after its battery runs out.
  • Not that running out of power will necessarily stop it them. Shinji's Unit 01 is the one who tends to run out of power, but he also tends to go berserk and kill the Monster of the Week regardless. Asuka is not so lucky.
    • Considering why exactly Eva-01 is able to outperform Eva-02 in Berserk Mode is not astonishing, if you understood whose soul resides in it...and that person may be the primary player in the series' massively complex and confusing conspiracies
• One Piece:
  • The effects of Chopper's Rumble Ball last for exactly three minutes. He can try it a second time if the fight lasts longer than that, but he loses control of his transformations if he tries, leaving him with no choice but to randomly transform and hope he gets what he needs. And if he goes for a third, well... things just get bad.
  • Luffy's Gear Third has a variation of this. While there's no set amount of time it lasts, when Luffy stops the technique, he changes into a chibi version of himself that's pretty much useless in combat; he stays this way for an amount of time equal to that he had just spent using Gear Third.
  • Luffy's Gear Fourth plays this straight. Maintaining it is such a strain that it automatically deactivates after a short time, leaving Luffy so drained that he can barely fight afterwards. For about ten minutes, he's incapable of using Haki at all.
  • Gear Fifth works similar to its predecessors, but has an even more harsh penalty on top of its time limit.
  • There's also Hero Water, which makes the drinker incredibly strong for five minutes, after which they die. This was only used once, for obvious reasons. Even worse, that one time accomplished precisely nothing. The target was Sir Crocodile, a Logia Devil Fruit user, so they couldn't have harmed him no matter how hard they tried. Crocodile didn't even bother humoring them with a "fight": he used his powers to turn into an intangible pile of sand, flew off into the distance, and simply waited for the users to die.
• One-Punch Man: Genos' upgraded cyborg body in the Monster Association arc had a special mode that could allow him to unleash his full power, but only for 10 seconds, or else he would run the risk of overloading and exploding.
• Pokémon Adventures:
  • Mewtwo could only fight for three minutes at a time after he was caught by Blaine, thanks to some trouble with his cloning involving some Applied Phlebotinum and Blaine's cells. Any longer risks Blaine's life and tires Mewtwo out considerably.
  • Yellow has a good number of powers, including heightening her Pokemon's level to a frightening point when under emotional stress. Using these powers, however, eats at her stamina like nothing else, and when she uses them too much, she falls into a sleep that cannot be externally disrupted no matter how inopportune the following situation.
• Record of Ragnarok: Zeus's Adamas form ramps up his durability to Nigh-Invulnerability levels, but he can only stay in that form for around 12-13 minutes. During his fight with Adam, not only is the time limit reduced to 5-6 minutes due to his injuries, but his flesh is almost being ripped to shreds due to the form's strain. He reverts back to his usual "frail old man" figure once his time is up.
• Rosario + Vampire: Whenever Tsukune got injured, Moka would inject him with her blood to heal him. At first, this would grant him temporary vampire powers as a side effect. After awhile it gets subverted, because the blood starts to take a toll on his body, and the transformation becomes permanent, with consequences. He recovers somehow and keeps the powers, so this trope becomes redundant.
  • Although, he's still at risk if his limiter is ever broken.
• Rurouni Kenshin: Shishio Makoto was once burned alive, damaging most of his sweat glands. As a result, he cannot fight for more then fifteen minutes, at which point he overheats and dies. In the final showdown, he goes over this limit and literally goes up in flames.
• Subverted in Super Dreadnought Girl 4946. Mana is told that it's okay to eat Tobita for a power boost as long as she spits him up within three minutes. In reality Tobita should have died the moment Mana swallowed him, and the three minute rule was a lie to convince Mana that she wasn't killing her boyfriend. The fact that Tobita actually survived was a surprise to everyone except Mana, and ever since then they kept the three minute rule simply because they have no idea about how long he can ACTUALLY survive.
• Tekkaman Blade turns into a mindless, berserk killing machine if he remains in Tekkaman form for thirty minutes.
• Wild Tiger's Super-Strength in Tiger & Bunny has a 5-minute time limit per activation, as does that of his partner, Barnaby. Midway through the series his powers get stronger but shorter lasting, whittling down to four minutes by the series finale episode, and one minute by the Where Are They Now epilogue with it looking quite likely he'll lose them forever. He ultimately loses his power at the end of the sceond season.
  • Season 2 introduces L. L. Audun, a vigilante Anti-Villain with his own Hundred Power. However, his is much stronger than Tiger and Bunny, and his cooldown is only one minute rather than an hour.
• In Tokyo Mew Mew, Alto, actually Ryou in cat form, can only remain as a cat for fifteen minutes or get stuck like that forever.
• Tomica Hyper Rescue Drive Head Kidou Kyuukyuu Keisatsu:
  • The Synchro Fusion with the Transporter Gaia is extremely powerful. The problem is that it only lasts 3 minutes.
  • Cyclone Interceptor's Force Field Mode is even more extreme, lasting for less than a minute.
• Yu-Gi-Oh! GX: The Contact Fusion forms of Neos, which is an Ultraman Copy, can only last for one turn and then they go back to the Fusion Deck (before the term Extra Deck was invented). To avoid this weakness, Judai has cards like Neo Space or Instant Neo-Space to keep them on his field.
• Yu-Gi-Oh! 5Ds: The Saviour (or Saver forms of Stardust Dragon and Red Daemon's Dragon can only last for one turn and then they go back to the Extra Deck, but unlike Neos, their original forms do come back on the field. But since they are so powerful, they usually win the duel during the turn they are summoned, it only happens once during the entire series.
  • And that one exception, Yusei just used a card to negate the return effect, which never shows up again.

Comic Books

• The DCU:
  • Justice Society of America: As his name implies, Hourman's Super Serum only lasts for an hour; he uses the phrase "Hour of Power" quite often too. The villain Per Degaton, who can accelerate time, is naturally a Man of Kryptonite for him. The second Hourman Rick Tyler also had the ability to spend an hour in a timeless dimension with his father. This eventually ended when Rick was mortally wounded, and all the time was used up to save his life. The android Hourman eventually gave his life in Zero Hour: Crisis in Time! instead of Rex Tyler, enabling father and son to return home.
  • Justice League of America: Android Hourman also had an Hour of Power, which gave him access to all sorts of cool time-manipulation abilities (just about the only thing he couldn't do was make his Power Hour last longer than 60 minutes). This was actually a self-imposed condition — prior to that, he had continuous access to his powers. He limited himself to explore his humanity.
  • The Green Lantern rings used to require charging every 24 hours, but this has gradually been changed to more closely follow a "battery" model, where the charge depletion depends on the use of the ring.
  • Doom Patrol: Negative Man could separate his energy form from his body for 60 seconds at a time. He had to act fast; If he didn't return to his body in time, he would die.
  • Superman:
    • All-Star Superman has a formula that gives whoever drinks it Kryptonian superpowers for 24 hours. When Lex Luthor takes it, Superman uses a gravity gun to increase Luthor's personal gravity 500 times — which only manages to slow him down temporarily. Thanks to General Relativity, the gun also makes 'Luthor's' 24 hours run down a lot faster, and his powers give out before he can finish Superman off.
    • This is based on old devices Superman had in the Silver Age which could do the same.
  • The H-Dials from the 1980s iteration of Dial H for Hero had a set hour time limit for the superheroic identities they bestowed upon the wearers, as well as an hour wait before the dialer could transform again (which was imposed whether the dialer used the previous transformation for the full hour, or voluntarily reverted before their hour was up). However, it was found in the final story arc that the H-Dials could be immediately passed onto another person (as long as that person hadn't used one within the last hour) to circumvent the limitation.
  • Teen Titans villain Shimmer can transmute any element or compound into any other. However, the change only lasts for a few minutes.
  • Wonder Woman (1942): Helen Alexandros can only change into the Silver Swan for an hour at a time. Eventually the fact that her flight abilities are not permanent catches up to her and she falls to her apparent death.
• Marvel Universe:
  • The Mighty Thor:
    • Originally, if Thor lost contact with his hammer for more than 60 seconds, he would change back to his human form. This limitation has since been removed, although it made a comeback when Eric Masterson, otherwise a normal human, became a replacement Thor by taking up the hammer.
    • In one story, his power had been halved, and a villain was beating the living daylights out of him. As a test, Odin granted Thor his full power for thirty seconds. Thor won. (Do not screw with someone whose titles include "god", no matter what they are the god of. If they're the god of something like "thunder" or "storms", don't even think it.)
  • According to one X-Men source, Rogue's power drain ability tends to last for about a 1:60 ratio — that is, for every second she holds it, she has what she took for 60 seconds. Life Energy and memories may work on a different scale, of course, and since it's possible for her to take powers permanently, this ratio breaks down the longer she holds on, but, well, A Wizard Did It. It was later revealed that the limits to her powers were psychological, not physical. After she was "reset" and her trauma-induced mental blocks restored, she could call up any previous power or memory she had absorbed at will, as well as be able to touch someone without draining them. That said, the 1:60 ratio was rarely outright stated to begin with, and it's very possible that later writers never heard of it, so it's more likely just a non-definite exponential ratio.
  • J2 of Marvel Comics 2 has a time limit on his transformed state that gradually gets shorter as his body matures and becomes better at using his powers.
• In Asterix, it wasn't established exactly how long does the Gaul Magic Potion last, but according to the 1999 Asterix and Caesar movie it is established that Getafix's magic potion works only for "about ten minutes". This is a big contrast to the original comic books where the magic potion did in fact work for many hours, such as one character drinking a ladelful of potion at night and retaining his strength well into the following day.

Fan Works

• In the Facing the Future Series, after getting control of his True Ghost Form which initially made him go savage, Danny learns he can only use it in battle for two-and-a-half minutes, and has to wait a full twenty-fours inbetween each use before using it again. While he has been tempted to stay in it longer, Sam makes him stick to his time limit.
• In The Echo Ranger, Tommy explains to Izuku that the Ranger powers require great physical condition and training in order to stay morphed for long periods of time. By the time he enters the UA, Izuku is able to stay morphed for about three hours on average in either mode. Once Melissa manages to create a second Echo coin for herself, she's able to stay morphed for about one hour when she uses it in combat for the first time.

Films — Live-Action

• Darkman, as opposed to Ultraman, needs to get out of light within 99 minutes. After that, the synthetic skin he uses for his masks dissolves.
• Project Power: Power is a pill that give people superpowers for five minutes, that is if the person taking it isn't killed by their powers before the time is up.
• Morbius (2022) sees the character reach this point after he transforms himself; he can initially use artificial blood to sustain his new enhanced state for six hours at a time before his body regresses to its diseased state and he has to drink again, but as time goes on this method becomes increasing ineffective.

Literature

• The Animorphs had two hours before they had to "demorph" into human form, or else be stuck as an animal. Used as a major part of the plot (one of the main characters was stuck from the beginning of the series), but suffered somewhat from a Two of Your Earth Minutes Running Gag. It also appears possible for someone with high willpower to demorph just beyond the time limit, but with greater difficulty. Note: There are instances in which the time limit can be reset. One book has Cassie get trapped as a caterpillar, but her natural transformation into a butterfly resets the clock. Also, the Ellimist has the power to restore someone's morphing ability after they have been mode locked.
• Isaac Asimov's "The Secret Sense": Martians can temporarily grant humans the ability to sense magnetic fields, but doing this once permanently burns out the part of the brain used, so it only lasts for five minutes.
• The Stormlight Archive: Inverted. Shardblades can be summoned out of thin air, but it always takes ten of the owner's heartbeats to do it (meaning you get it faster if your adrenaline is rushing, a nice feature for a weapon). In this case, it's not an exact time until the power ends, but an exact time until the power begins. Also, this only applies to "dead" Shardblades, which are formed from spren who were killed when their Radiants forswore their Oaths during the Recreance. Living Shardblades owned by Radiants who still hold true to their Oaths can be called up instantaneously. Also in Oathbringer, during the climatic battle Adolin's dead blade appears in only seven heartbeats.
• In The Expanse Clarissa Mao has an adrenal implant that gives this, giving her enhanced physical abilities at the cost of passing out as soon as it wears off.
• As a variant, in the Russian kids book ''Marusya Will be Back Yet", one of the characters is a Lilliputian wizard who only has powers between five minutes to an hour and the exact hour (i.e. from 11:55 to 12:00).

Live-Action TV

• The Animorphs television series has the extreme Exact Time to Failure version: Ax is close to being trapped in human form, counts down the last few seconds to a nearby teammate, but is finally able to get away and has none of the difficulty changing back that the book versions had when cutting it close. This would suggest that changing back after 1 hour, 59 minutes, and 59 seconds is no different from changing back after five minutes, but changing back at 2:00:00 is completely impossible.
• It's kind of a stretch but The Big Bang Theory is kind of written like this with Raj and alcohol. When his drunken stupor wears off, he's powerless to talk to people of the opposite sex.
• Lockeand Key has a few keys like the time shift key that are time sensitive.
• Tokusatsu: Basically, the overwhelming majority of "Giant Hero" series have the three minute rule, because the Ultra Series writers worked on most, even if the series is not officially an Ultraman series (also because of Follow the Leader in some cases). Either the chest or the helmet will always have the light that lets him know when time is short. As per the Once an Episode narration: "The energy that Ultraman receives from the sun diminishes rapidly in Earth's atmosphere! The warning light begins to blink! Should it stop completely, it will mean that Ultraman will never rise again!"
  • Ultraman popularized this trope for live-action Japanese superheroes. His Bizarre Alien Biology makes Earth's atmosphere harmful to him, but he stores enough solar energy to last for three minutes, marked with the Color Timer on his chest that goes from blue to blinking red as this runs out. Interestingly, the weakness was actually a last-minute addition when the writers realized Ultraman needed a weakness to increase tension, but it also conveniently serves as a way to control the budget for Kaiju of the Week sequences. The same goes for the majority of Ultra Series works.
    • Ultraman Leo and Astra also find Earth's atmosphere harmful, but due to them hailing from the planet L77 of the Leo constellation, they can only store solar energy for two minutes and forty seconds before their Color Timer starts flashing red as it depletes.
    • Averted in some Ultra Series, such as Ultraseven, Ultraman Gaia, and Ultraman Nexus, where the hero can stay for as long as he likes. The Colour Timer (or Head Lamp in Seven's case) only flashes for them if they're in danger of dying, acting more like a video game warning for low HP instead.
    • As for Ultraman Tiga, he's Earth-born instead of being from the faraway world that the other Ultras hail from, so the Earth's atmosphere doesn't threaten his life... but he doesn't have an unlimited battery. The light will begin to flash, giving him about as much time as his predecessors. If it runs out, he demorphs - better than being directly killed by timing out, but if a Kaiju is trying to murder you, finding yourself as a squishy human at its feet who can't transform again until enough recharge time has passed is not a good thing! We also get a rare instance of an Ultraman changing and fighting small-sized Mooks before growing. The human-size battle went on for some time and didn't seem to take away from the time limit for the giant-size fight later.
    • The Alternate Continuity Ultraman manga has its own take on this trope. Shinjiro's Ultrasuit can operate indefinitely under normal conditions, but in a pinch, the suit's limiter can be disengaged to increase his capabilities exponentially. This Super Mode can only be maintained, as is standard for the series, for three minutes at a time, and is indicated by the suit's core turning red in a similar vein to the original Ultraman's Color Timer.
  • From the same studio there's also Fireman, who cannot stay in his Agan form for more than 3 minutes due to sunlight being harmful to Agans.
  • Mirrorman, another Tsuburaya Productions hero, didn't start with this, but gained his own version of the Color Timer when the show went through a retool at around its midway-point.
  • Denkō Chōjin Gridman: Gridman is really hard on the computer that hosts him; three minutes is the limit before Explosive Overclocking takes place.
  • Iron King is water-powered and burns through his supply in just one minute, demorphing.
  • There's the '70s superhero Kaiketsu Zubat, who explodes if he wears the Zubat suit for more than 5 minutes. Justified in-show as being a Super Prototype, finished by the guy himself even though it's out of his field. Worse, the time spent catching up with the villain counts (compare to the Ultras, who can extend their time by conserving power or shorten it by using too much at once. Three minutes sitting in a comfy chair, if you had one big enough, wouldn't be the same as three minutes of battle; not so Zubat.) so he barely has enough time before the indicator on his helmet makes a full rotation and his visor opens, signifying the shutdown that prevents "kaboom".
    • He tried to upgrade it to give himself more time once. Good thing he tested it on a mannequin first! When five minutes passed and all seemed well, he was thrilled... then about three seconds after that, the mannequin was completely crushed and blown apart at the same time, somehow. That Could Have Been Messy!
  • The Makai Knights of GARO have exactly 99.9 seconds to fight in their armored forms before it runs out. They can choose to exceed the time limit if they want, but the results are... not pleasant.
  • Zone Fighter, created by Toho of Godzilla fame, plays with this; the title character's giant form has the "Zone Meter," a device on his waist resembling a belt buckle, which functions as Zone's Color Timer, with his power source being proton power, supplied to him via a "Zone Marker" in the antenna on his head. Like his contemporaries, Zone can only assume his giant form for a limited amount of time; however, unlike them, Zone can replenish this energy, either through energy beams fired from Zone Angel and Zone Junior, or from Smokey, the team's Cool Plane. Smokey can also launch spare Zone Markers directly onto Zone Fighter's head. Even with these backups, though, Zone can still be forced to demorph, either through depleting his energy or taking too much damage at a given time.
• A version of this occurs in Stargate SG-1, where a stargate can only remain open for about 38 minutes due to power limitations. However, with sufficient power (like a black hole, as the SGC found out accidentally in one episode) a wormhole can remain open indefinitely, which also comes in handy on occasion.
• Power Rangers/Super Sentai:
  • The fake Sixth Ranger White Racer of Gekisou Sentai Carranger can transform her vehicle the Radiacar into a miniature mech with a Hello Kitty like face called the Radiacar Robo. But in its robot form it runs out of power in only one minute. But that one minute proves to be plenty of time to give the Monster of the Week a beating and set the tied up rangers free so they can finish the fight. The second time she brings it out it has been upgraded to be able to grow to the same size as the ranger's mechs.
  • Silver Ranger/Megasilver from Power Rangers in Space/Denji Sentai Megaranger had a transformation time limit of 2.5 minutes. (In Megaranger it was due to the suit being a Flawed Prototype; in Space it was due to the time the Silver Ranger spent as a Human Popsicle.) And then he got over it when the bad guys tried to exploit this. With lots and lots of research.
  • The Storm Megazord/Senpuujin in Power Rangers Ninja Storm/Ninpuu Sentai Hurricaneger had a special form that lasted 1 minute before switching back (although as the series went on it went transformed for about 2 mins).
  • The Engines from Engine Sentai Go-onger can maintain their large forms in our universe for 10 minutes before rusting.
  • In Power Rangers S.P.D., Kat was given an expendable morpher for one episode to help her team which would only work for one hour. Her counterpart in Dekaranger didn't have this restriction and simply chose not to transform outside of special circumstances.
  • Power Rangers Megaforce had a time limit imposed on the Rangers’ Power Copying abilities, as a narrative reason as to why they ever bothered using their own weapons instead of relying on those of the past heroes. The source material glossed over why they went back to their base form for the Finishing Move. (Aside from the obvious reason.)
  • In Tokumei Sentai Go-Busters, there's an indicator of how much of the superfuel "enetron" is being burned. When it comes to finishing a fight, faster is better, though they've got way more time than many of the other Toku examples on this list.
  • In Power Rangers Dino Charge/Zyuden Sentai Kyoryuger, each Ranger carries a set of three or four batteries (called Dino Chargers in the former and Zyudenchi, or "Beast Batteries", in the latter) that have a number of uses, but could only be used once before needing to be recharged. If a Ranger transforms, summons a weapon, uses a Finishing Move, and summons their mecha in quick succession, then that's pretty much all their batteries drained and they're stuck for a while.
  • Ressha Sentai ToQger: The Rangers can only transform for 30 seconds while inside of a shadow town. Since the core five Rangers can share their Transformation Trinkets with each other this means they can extend their transformation time to 150 seconds if only one of them fights. Hyper mode, which only one Ranger can use at a time, also extends the time limit a bit further. The Sixth Ranger also is limited to only 30 seconds in his Ranger form while in a shadow town; he also has a monster form that isn't affected by shadow towns but he hates using it. Once the time limit is reached the Rangers have to wait a few minutes before they can transform again. In one episode, two of the Rangers get shrunken and trapped in a dollhouse and find that they can only transform for a few seconds and thus have to use their brains to find a way out.
  • Uchu Sentai Kyuranger has the chief don a purple Ranger suit, but it had a time limit of a few minutes due to the fact that he jury-rigged his Transformation Trinket from a component that was intended for enabling special attacks, not for transforming. That component eventually got upgraded into a 'transformation' type by The Power of Friendship or something, removing the limit.
  • Mashin Sentai Kiramager: The Rangers' Super Mode automatically deactivates after 100 seconds to prevent it from burning out their bodies. This limit was included since the Rangers saw a villain give a bunch of Mooks a power boost that made them into unkillable zombies but caused them to drop dead after a while and that a monster that had been boosted by the same stone they used to power their Super Mode was unable to contain it for long.
• Kamen Rider:
  • Kamen Rider Stronger can sustain his Super Mode for only a short time before the implant that generates it overloads and goes 'kablooey.'
  • Faiz Axel Form in Kamen Rider 555 only worked for 10 seconds before shutting down. While this seems short compared to some of the other examples on this page, keep in mind that this is 10 seconds of Super-Speed.
  • In what is surely a Mythology Gag we have Accel Trial Form from Kamen Rider Double, which must complete its Maximum Drive within 10 seconds after activating it.
  • Kamen Rider Ex-Aid has the Muteki ("Invincible") Gashat, which grants its user video game-like invincibility. And like that kind of invincibility, it only lasts a short time... too bad Kuroto Dan decided to gloat of its power while facing down Chronos that one time...
  • Kamen Rider Build has the Hazard Trigger, which can only be used for a short time before driving the user uncontrollably berserk. To hammer it in, when it's used, the suit turns black. Also, the suit's Computer Voice adds a cheerful "Yeeeeah!" when announcing form changes; Hazard forms instead get "Oh, no!"
• Stargirl (2020) gives Rick Tyler a literal hourglass to flip over and activate his power. Seems like villains could keep an eye on the sand and use that against him...
• Planet Ajay: Ajay's Ring of Power transports him to Planet Ajay in a sparkling suit... but only for 30 minutes in every episode. After that, he has to go back to Planet Earth.

Tabletop Games

• In Crimestrikers, Nyx Marama has the power to make her body (or part of it) glow in the dark for up to an hour at a time.
• Deviant: The Renegades: The Depletion scar limits the use of entangled powers. The higher the magnitude, the longer recharging takes, until at the highest level, a power can only be used once and then all entangled powers take hours to recharge.

Video Games

• In Granblue Fantasy, players who belong in a Crew can take advantage of the Strike Time mechanic of the game. The Crew's captain can set 2 specific hours of the day wherein all of their crew members will benefit from its effects. Strike Time provides 100% Charge Attack Bar for all party members (including those in the backline) at turn 1 in these specified hours.
• Metroid Prime 3: Corruption has Samus' Hypermode, which actually has two timers: 10 seconds after activation, the Hypermode turns into Corruption, causing the meter to rise over time (as does being hit by certain attacks), and 25 seconds after activation, the mode is automatically turned off. To be fair, the second time limit actually makes sense as an internal safety measure of her PED suit.
  • True to form, the Corruption can be used as a Dangerous Forbidden Technique by abusing the recharge, at the risk of total corruption.
  • The limits of Hypermode are linked to GF safety restrictions and Samus' internal Phazon stability. When Samus arrives on Phaaze, she has to manually override the venting mechanism and discharge all her pent-up Phazon to avoid immediate terminal corruption, whereupon she faces a different kind of timer.
• A number of powersets in City of Heroes have abilities along this line. The best example is probably the defensive powersets which frequently include an "uber-mode" power that renders the character nearly invulnerable for a few minutes but has a very long recharge time.
• Several units in Super Robot Wars have command Super Modes that last for a limited number of turns. By the endgame, most of such limitations are removed and become straight Mid-season Upgrades.
  • The Gran Kaiser combines with its supporting mecha and forms the titular Gravion; unlocking new attacks along with five subpilots.
  • The Unicorn Gundam transforms into Destroy Mode, boosting stats and unlocking its strongest attack. Unusually for the series, the turn limit isn't removed in Jigoku-hen, meaning Banagher gets stuck in the sidelines for the endgame.
• In Robot Alchemic Drive, Vavel has a Volcanic Mode that increases its attack power significantly, but can only be used for three minutes. Exceeding the time limit will cause Vavel to overheat and self-destruct, so players must finish the fight before then.
• In Kid Icarus: Uprising, Pit can't fly despite being an angel. At the start of every level Palutena grants him the Power of Flight, which allows him to fly at very high speed and boosts his attack power. These segments make up the Rail Shooter portion of the game. However, it only lasts for about five minutes and it needs time to recharge. Breaking the time limit or using it back to back will cause Pit's wings to catch fire. There's several parts of the game where they have to watch the clock and find somewhere to land quickly, and near the end, Pit overuses it to save Dark Pit and nearly dies.
• Sundered: As of the August 2017 patch, the player character can obtain various temporary buffs from randomly-generated “Backer Rooms”. These buffs last for a few minutes and can be defensive (such as giving the player increased Armor) or offensive (such as making enemies explode when they die, thereby damaging nearby enemies).
• In Final Fantasy XV, the Magitek Nanosuit grants Noctis and his party approximately 30 minutes of complete invulnerability when donned. After the effect wears off, it takes about 24 hours for it to recharge, although they can still be worn.
• In the Pokémon games, Regigigas is an inversion. Only 11 other Pokemon meet or exceed its 680 base stat total, and only two exceed its base Attack, but it has to suffer 5 turns of weakness to get the benefits. This can be negated entirely through the use of Gastro Acid, a move that disables a Pokémon's ability (which, as it turns out is what limits Regigigas).
• Super Smash Bros. has Cloud's Limit Break and Wii Fit Trainer's Deep Breathing, which give the character in question a significant increase in power but last a limited time. Cloud initially didn't have the time limit, but it was added in Super Smash Bros. Ultimate due to players using limit to patch his weak recovery rather than make him more powerful, which led to Cloud having no real weaknesses in practice. Shulk's Monado forms are also time limited.
• Throughout The Elder Scrolls series, the ten playable races each come with various "Racial Powers" in this vein. Some, like the Bretons with innate magic resistance and the Altmer with innately higher Magicka, have their powers "always on". However, most must activate this power, where it only has a short duration (typically 30-60 seconds depending on the game) and, most importantly for this trope, can only be activated once per day. Examples include the Argonian's "Hist Skin" (which gives them a dramatic but temporary Healing Factor), the Orc's "Berserker Rage" (which doubles the damage they deal while halving the damage the take), and the Bosmer's "Beast Tongue" (which allows them command an animal) among many others.
• In Pokémon Sword and Shield, Pokémon can use their Dynamax or Gigantamax forms, granting boosted HP and powerful Max attacks, for a maximum of three turns before automatically reverting. The only exceptions are Raid Bosses (which are empowered by their dens) and Eternamax Eternatus (the source of the Dynamax phenomenon). This is different from other transformations like Mega Evolution, which lasts until the battle ends, and Forme Changes, which last as long as their conditions are met.
• Vampire Survivors: Certain characters have a gimmick where, upon killing a given number of enemies (that increases with each activation), they get thirty seconds of massively boosted stats and occasionally additional temporary weapons. As of this writing, they are Impostor Rina from the Emergency Meeting DLC (who gets decent Speed and Cooldown boosts and a massive Might boost) and Menya Moonspell from the Legacy of the Moonspell DLC, who becomes outright invincible, gets triple Might, triple Speed, an extra Weapon, a Cooldown boost, and some Curse sprinkled on top to get even more enemies coming. You can unlock a permanently-boosted "Megalo" version of each if you kill 100.000 enemies with the regular versions, too (and yes, Megalo Menya is still unkillable for the whole thirty minutes).
• Xenoblade Chronicles 3 has the Interlink function, where an entity from Keves and an entity from Agnus can merge together to become a more powerful singular being that can regenerate from the worst damage so long as their core is intact. However, there is a time limit to it, signified by loud beeping as it nears its end. In gameplay, Ouroboros will disengage the Interlink to allow the system to cool down. In narrative, however, a terminal overload will always result in an Annihilation Event centered on the misfortunate Interlink.

Webcomics

• In Endstone, Kyri explains the need to recharge.

Web Original

• In the Whateley Universe, Dash has super-speed, super-strength, and Nigh-Invulnerability. But it looks like he only has it for a matter of minutes, and can't call it up without a lot of effort ahead of time. Word of God finally explained it: Dash is some kind of Energizer and can focus to make his body stronger and tougher and faster, but it only holds up for ten minutes or so, and it takes about that long for him to power up. After, he needs hours before he can do it again.
• Many of the SCP Foundation artifacts have specific hard time limits, although the round units are generally averted. For example, SCP-431-ARC sets its wearer on fire after 22 hours and 17 minutes of being worn.
• RWBY has the brutish assassin Tock, whose Semblance allows her to boost her Aura to an extreme level, letting her become functionally invulnerable for sixty seconds. After this time elapses - which she tracks using an old-fashioned alarm clock/stopwatch on her belt - her Aura collapses, leaving her vulnerable again. It gets her beheaded by her target Maria Calavera, who wasn't quite as helpless as she'd thought.
  Tock: And these... are the last sixty seconds of your life.
• A significant concern for gen:LOCK pilots is "uptime", i.e. the maximum time their consciousness can stay uploaded to their Holon's cyberbrain. Running on a computer does not leave human neural processes unaltered, and if they change too much, they won't be able to properly download back into their living brains. To make the best use of uptime, the pilots have to be physically transported to operation sites, uploading at the last possible moment and downloading as soon as the mission ends. In addition, overclocking of the cyberbrain and emotional distress both consume uptime at an increased rate.
• In the Youtube Poop Skellington's Revenge, Spongebob uses an "emergency gear" that promises "120 power-packed seconds". It temporarily transforms him into a (ridiculous-looking) powered up form, allowing him to effectively fight the Black Hiver and his army, but, as advertised, runs out after precisely 2 minutes.

Western Animation

• Ben 10.
  • The original series Omnitrix of Ben 10 had a time limit that is supposed to be ten minutes Earth time, but in practice differed from use to use. It supposedly lasted ten minutes, and took ten minutes to recharge, and there was no switching forms or demorphing before those minutes were up. It's stated on several occasions that the purpose of the time limit is to prevent permanent damage to the user's DNA but this is ignored if Ben's life is in immediate danger.
  • The rules changed in later series; usually, the more time he had, the less control he had of the other aspects of how the Omnitrix would behave. In Omniverse, the time limit was very random; he's changed, tried to fight, but immediately changed back before he can make a move; he's also stayed in one form for half an episode. He often had little to no control over which alien form he got. The up side was that when the Omnitrix did time out, it's always ready to go again in under a minute.
  • As seen first in the episode "Back with a Vengeance", every so often, Ben's Omnitrix has "Master Control" activated and gains full control, but Status Quo Is God; he only gets Master Control on rare occasions, and he never gets to keep it longer than the climax of the episode in which it happens. Elseworlds and Time Travel episodes have given us a glimpse of adult Ben, who has Master Control full-time.
• Roger Ramjet's proton pills gave him "the power of twenty atom bombs for twenty seconds".
• Superboy of Young Justice (2010) normally has Super-Strength, Super-Toughness, Super-Senses, and super-leaping abilities due to being a half-human clone of Superman. In the episode "Agendas", Lex Luthor [[spoiler:who is the donor of Superboy's human DNA gives Superboy patches called Shields. When Superboy uses one, it suppresses his human DNA, which grants him the rest of Superman's powers (Flight, Heat Vision, more Super-Strength) for one hour. However, it also fills Superboy with rage.
• In Avatar: The Last Airbender, Sozin's Comet grants firebenders incredible power: the first time they used it, they managed to commit near-total genocide on the Air Nomads, with the protagonist being the only survivor, and that's arguably because he was frozen in an iceberg when it happened. The second time it comes, Phoenix King Ozai plans to use it to burn down the Earth Kingdom; from what we saw, given how much power the Comet granted, he might have pulled it off. However, it's not clear how long the Comet's effects remain, with guesses ranging from a few hours to a few days.
• Gummi Bears: Gummi Berry Juice lasts for about a minute or so. A Gummi Bear can, so long as they have more juice, drink it again immediately to get their bouncing powers back, but for humans it only grants Super-Strength once per day.
• The titular Kulipari of Kulipari: An Army of Frogs are dart frogs that can use their poison to boost their strength to considerable degrees. They can only do this for so long before they need to rest and recharge, as overdoing it risks burning their poison out forever.
• Miraculous Ladybug: When Ladybug or Cat Noir use their special abilities (Lucky Charm and Cataclysm), it starts a Magic Countdown of five minutes until their powers run out and they de-transform. This applies to the temporary allies they recruit as well. However, this is eventually revealed to be due to their youth and inexperience rather than an innate limit, as older, more experienced people with the same power source don't suffer from this drawback.
• Beast Wars: In the episode "Power Surge", Terrorsaur gains a significant power boost from a floating mountain of energon, but this boost only lasts a few minutes before he reverts to an exhausted state of his original power level. He's able to recharge, but he subsequently lost his power when the energon mountain was destroyed, and the cast never discovered a power source on that level again.
• A villainous example from The 13 Ghosts of Scooby-Doo. Nicara's trance of love and power draining kiss only work on Friday the 13th, hence why she's keen to acquire the powers of Vincent Van Ghoul before midnight. Fortunately Scooby and the gang manage to delay her long enough for time to run out so they can send her back to the Demon Chest.
• In the Sesame Street spinoff Mecha Builders, the robotic Cookie Monster, Abby Cadabby, and Elmo have a Ultraman-esque "Cookie Clock" on their chest counting down the time they can spend in a Humongous Mecha state.
• The Transformers: The Terrorcons can only remain in their combined form, Abominus, for a short period of time before a timer forcibly splits them apart. This is a self-imposed limit due to how destructive and uncontrollable Abominus is. The Seacons of the same series also imposed an automatic timer for their Piranacon combination. The Seacon's shared love of hunting Autobots makes Piranacon unusually intelligent and focused for a combiner, but it also makes him obsessed with hunting his prey. Without the timer, Piranacon would refuse to separate and continue hunting until he drained his entire energy supply and shuts down.

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