Normally, sleep talking is harmless, except for when things like secrets are accidentally blurted out. But then it gets to the point when you start using your superpowers in your sleep. That's when it becomes less harmless...
A trope that usually occurs with those who wield magic or superpowers. They may be so used to using their powers they may accidentally start using them out of night terrors or some kind of instinct or muscle memory. It may also happen when someone uses superpowers in response to what happens in their dream, while they're still sleeping. Whatever the case, nobody nearby, not even the user themselves, will be safe from these rogue, unpredictable superpowered actions. But in some instances it may be justified if their ability requires them to sleep, such as Astral Projection and dream-related abilities (Dream Walker, Dream Weaver, etc).
Sub-Trope of Power Incontinence and Talking in Your Sleep. May result in Oh, Crap!, Unwitting Instigator of Doom, or Nice Job Breaking It, Hero! if it has disastrous consequences. Compare Unconscious Objector.
- Cardcaptor Sakura has an episode where after receiving a magicked New Year fortune from Eriol, she dreams that she activates her magic wand and morphs the Dream Card from a Clow Card to a Sakura Card. She then wakes up and finds that she has activated her wand and transformed the Dream Card while asleep.
- In My Hero Academia, Izuku briefly suffers from night terrors where he is explicitly shown the creation of One For All by its first wielder, waking up to find that he has accidentally wrecked his own room in his sleep.
- In one omake, Yamato deals with Naruto, who is snoring loud and throwing weapons in his sleep. He even creates a friggin' Rasengan in his sleep, which prompts Yamato to create a bunker to hide in using Wood Release.
- Another omake has Yamato dealing with Naruto and Kiba, who are both using their signature jutsus on him in their sleep. Yamato ends up tying them up, only to now have to deal with Shino, who is about to utilize his insect swarms against him in his sleep.
- One Piece: Cavendish has a Superpowered Evil Side called "Hakuba" that manifests whenever he falls asleep. He gains Super Speed during such, but he will indiscriminately attack anyone in vicinity.
- Disney Adventures had a short comic based on Aladdin called "Poof Spoof", in which the Genie keeps casting magic in his sleep, accidentally transforming Aladdin and Abu in amusing ways.
- Green Lantern: Kyle Rayner stopped wearing his ring to bed after his dreams about his dead girlfriend began manifesting in the real world.
- The reason Spider-Man got rid of his symbiote costume, to begin with, was that it took him out to fight crime while he slept.
- Dungeon Keeper Ami: After Ami tries to get a good night's sleep with a sleep spell, it's discovered that sleep-keeping is possible, pulling General Jadeite to be a teddy bear, and pulling him back, if they manage to get away.
- Triptych Continuum: Triptych:
Dream-casting: a sign that a unicorn had pushed herself past her limits to the point where the subconscious took over and started implementing designs of its own.
- Dean Koontz's novel The Bad Place. Frank Pollard has a problem: he uses his power of Teleportation while he's asleep. Even worse, he suffers a Teleporter Misfire effect that causes a Teleporter Accident: he regularly merges materials into his body when he teleports.
- In Harry Potter and the Philosopher's Stone one of the unconscious ways of Harry using magic (before knowing it exists or that he is a wizard) is regrowing his hair in his sleep after Aunt Petunia cut it into a terrible hairdo.
- Lilith's Brood: Jodahs has bouts of Power Incontinence as his Biomanipulation powers develop during his species' equivalent of puberty. They're worst in his sleep, when he regularly mutates himself and any organic matter he's touching — a problem, since their entire village is a single Organic Technology organism.
- In Monday Begins on Saturday, the narrator describes having a dream about some giant mosquito-like creature, and then waking up because it tries to bite him. He remarks he must have spoken the materialization formula while asleep.
- Near the end of the Russian sci-fi novel Moon Rainbow, protagonist Andrey Tobolsky discovers that he is no longer a regular human after waking up in the middle of the night and finding himself floating comfortably two meters above his bed. He then proceeds to turn electronics on and off with his mind and to walk through a wall, just to test out what else he can do now.
- The Wheel of Time: Discussed when Mat learns that Rand can channel the One Power — a dangerous ability for any man. One of his fears comes from an urban legend of a male channeler who pulverized his surroundings in his sleep, so Perrin sarcastically suggests that they share a bed for safety. It's later revealed to be impossible to sleep-channel except for a few dream-related abilities.
- Whateley Universe: Phase has phased through matter while in his sleep before.
- In episode one of the 90s Sabrina the Teenage Witch, Sabrina levitates over her bed while she's asleep.
- In one of the early season episodes of Smallville, Clark dreams of flying to go see Lana, the girl he has a crush on. In reality, he's hovering over his bed, hinting that he'll one day be able to fly, a power he won't fully develop until the final episode of the series ten seasons later.
- In the Star Trek: Deep Space Nine episode "The Alternate", an unknown gas affects the changeling Odo. When Odo is regenerating (i.e. sleeping), he unknowingly transforms into a different sort of changeling, only this "Mr. Hyde" version is mindless, reacting according to Odo's current emotional state. It takes a few attacks for everyone to figure out what's going on. Odo even investigates the attacks committed by his other self.
- In an episode of The Worst Witch, when Julie Hubble gets powers, she levitates in her sleep.
- Raising Dion: Besides Power Incontinence, this is one of the problems Dion faces when his superpowers first begin to manifest.
- Pokémon has the moves Snore and Sleep Talk, which can only be used while the mon is asleep. Snore inflicts direct damage to the enemy and has a 30% chance of making the enemy to flinch, while Sleep Talk attacks using one of the four attacks randomly.
- There are at least two Pokémon noted to attack while sleeping; Abra, and Komala. Komala actually spends its entire life sleeping without waking even once, but Abra grows out of this after evolving.
- The main premise of Rayman 3: Hoodlum Havoc is that the fairy-like Lums have turned into evil Hoodlums thanks to the influence of the black Lum Andre. However, since Lums only turn into evil black lums if they were touched by Andre or spooked, this begs the question of what turned Andre the original black lum, evil. In a flashback, it's revealed that it was actually Rayman's Floating Limb hands, which wandered off while he was asleep and scared a Red Lum so bad that it turned into a black lum, thus explaining Andre's origins.
- In Tales of the Questor, racconans have innate magic and a tendency to unconsciously cast illusions of their nightmares in childhood. In one arc Quentyn discovers that one kit's night terrors have been attracting magic-eating wights.
- Although it doesn't happen in Grrl Power, this is one of the worries Sidney exposes to her therapist after she starts having post-traumatic nightmares: She reminds the doctor that she has the equivalent of a very powerful laser cannon always floating at hand and she doesn't want to fire it accidentally by lashing out in her sleep. Dr. Frost helpfully prescribes a pair of mittens.
- The DC Super Hero Girls short "#SuperSleeper" revolves around Supergirl flying all over Metropolis in her sleep with Batgirl trying to keep her out of danger and is unable to wake her up.
- In the DuckTales (1987) episode "Superdoo", Doofus Drake's first brush with the strange powers granted by an alien rock he found occurs while he's asleep. He flies out of the cabin while asleep and wakes up flying over the countryside.
- Final Space: In the season 2 episode " The Grand Surrender", Ash accidently uses her powers in her sleep while she has a nightmare in which she is fighting the Serpent God Werthrent. She ends up blasting a hole in the room of her wall, and Nightfall has to wake her up to prevent further damage.
- Monster By Mistake: After getting fed up with the annoying antics of school bully Billy, Tracy accidentally casts a spell in her sleep the following night that turns him into a giant blue gorilla.
- Star vs. the Forces of Evil:
- The whole episode "Sleep Spells" is dedicated to this trope. Star is constantly casting spells in her sleep with Marco trying to find out why. It turns out she was doing it to protect herself from Princess Smooshy, a fugitive from St. Olga's Reform School who is trying to steal Star's face to (extremely poorly) disguise herself.
- In the season 3 episode "Sweet Dreams", Star discovers she's been "dipping down" in her sleep, and travelling between dimensions in her Mewberty form. When her sleep-portaling starts to prove dangerous in "Night Life", she spends the episode "Deep Dive" trying to get to the bottom of the mystery.
- In X-Men: Evolution, Kitty Pryde's phasing powers first manifest in her sleep as she has a nightmare. She falls from her bedroom to the basement. Her parents want to pass it off as sleepwalking, until they see her blankets, half in and half out of the ceiling.
- In Static Shock, shortly after being exposed to Bang-Baby Gas, Static goes to sleep. His body then starts magnetically attracting every metal object in his room, with some of it stuck to him when he wakes up.
- Steven Universe:
- The title character has several Psychic Powers, almost all of which requite him to be asleep. Like all of his powers, he discovers them accidentally.
- Gems don't have to sleep, and the one time Pearl is known to have in "Chille Tid", her Mental Picture Projector powers unknowingly shows everyone her dreams.