Power Strain Blackout

It can be hard to show all the aspects of a fictional ability since such a thing does not have any Real Life context to which the audience can relate. So when a creator wants to show that using a special power takes a toll on a character, he will often have the character faint afterward.

This is especially true when the character uses a power for the first time. Presumably, the strain of using it is too much for him, causing his mind to shut down in self defense.

Frequently used for powers that aren't very flashy in order to make them seem more dramatic, such as telepathy and other Psychic Powers. It's also frequently a characteristic of The Chick, a Faux Action Girl, a Non-Action Guy and other non-combat oriented characters.

If the fainting is a symptom of a more serious health problem, it's also Heroic RROD. When it happens the first time a power is used, it's related to How Do I Shot Web?. Can be a form of Blessed With Suck.

If the collapse is after a dramatic moment, especially a battle, and is used to skip the boring aftermath, it's Post Dramatic Stress Disorder.

Compare to Fainting Seer, which may overlap for Seers.

Anime and Manga

 * In Metal Fight Beyblade, Madoka faints after using her bey to save Kiyoya's Leon. It's explained as her "not being used to blading."
 * Bleach: Jakuho Raikoben severely drains Soi Fon's reiatsu, enough that it usually takes her three days to recover before she can safely use it again. Otherwise, this happens.
 * Vision of Escaflowne: Hitomi's ability to see into the future, via Tarot Cards, often has this effect on her afterwards. It's eventually revealed that both the duration and the severity of her fainting spells is determined by her emotional state. Meaning, the greater her anxiety, the greater its toll on her following her vision; not to mention the part about
 * In Soul Eater, Sid collapses after using his power to get the main characters and Stein outside of the trap set for the whole school. In fairness to him, he had just nearly been blown up then rushed all the way back to Death City.
 * Dragon Ball Z: When Gohan first goes SSJ2 he triggers it for only a second then passes out. This was seen in one of Goku's flashbacks of their training in the time chamber and was the moment that convinced him that Gohan could beat Cell if he could sustain that power. Which he did.
 * Sailor Moon usually faints or at least collapses and loses her Super form after using her Rainbow Moon Heartache attack in the S series, although that restriction on her Super form doesn't apply during SuperS, probably because she's using a power source other than the Holy Grail in that series. She also has this problem in the first few episodes of Stars, when she first tries to become Eternal Sailor Moon, and like with SuperS, the problem disappears once that becomes her default form when the Animamates start appearing.

Comic Books

 * U Go Girl from the short-lived Mike Allred X-Factor. Her power would literally drain her energy and she'd more than occasionally pass out after using her whirly teleportation.
 * In early issues of Runaways, Molly would black out from exhaustion after a throwing a single punch. As she got more used to it she wouldn't pass out, but would still need a nap after using her powers.
 * Many telepaths of the various X-Men incarnations do this at least once in almost all of their adaptations.
 * Starfire, in her very first appearance in the Teen Titans, faints after using her powers.
 * Rogue in X-Men faints after some time if she absorbs the powers of a sufficiently strong superpowered person, such as Magneto.
 * Storm in X-Men passed out in mid-air after powering down a planet-threatening supercell of her own creation (Dr. Doom had trapped her as a statue and creating the supercell was her hysterical claustrophobic reaction to being trapped thus).
 * At the beginning of Ultimate X-Men Storm had a tendency to faint, not from the use of power itself but from the mental effort required to reduce collateral damage - since she had no experience with aiming her lightning.

Film - Animated

 * The Secret of NIMH: Also happens to Mrs. Brisby, immediately after the film's climax, wherein she uses The Stone for the first and only time to move her home. She collapses as its power subsides, then passes out.

Literature

 * In Eragon, Eragon's first attempt at casting combat magic caused him to lose consciousness because it took a large amount of energy out of him at once.
 * Alaric Morgan is apt to do this, since he's a bit of an overachiever and Deryni powers are physically taxing to use. In High Deryni, Morgan tries to contact Derry mentally (sending a Call) during the reconciliation service for himself and Duncan and faints from the effort; Duncan makes the excuse that his cousin isn't used to fasting. He also collapses from overextending himself to Call on campaign in The King's Justice, and Kelson scolds him for pushing himself too hard.
 * Physical exhaustion is the main symptom of overchanneling in The Wheel of Time, even to the point of unconsciousness. In extreme cases it can also cause a permanent loss of one's powers.
 * In the Dresden Files books, wizards feel fatigue when they use a lot of magic. Pushed too far, it certainly can cause a blackout.

Live-Action TV

 * Willow, of Buffy the Vampire Slayer, often collapsed after over-exerting herself during spellcasting.
 * Smallville: When Chloe first uses her healing power, she collapses so completely doctors think she's dead. (She actually takes on the person's injury, but didn't know that, and Lois had apparently been killed. It looked as she had traded her life for Lois's, but thankfully, she got better. She used her power to that degree once more, and stayed apparently dead for days.)
 * Kamen Rider Blade: The title character passes out after all his early uses of King form. So does anyone standing close enough to actually witness him using his final attack on a Monster of the Week. King Form is one of KR's 'so powerful it may be too much of a good thing' modes, such as were seen back in Kamen Rider Kuuga.
 * Kamen Rider OOO sometimes passes out after using a full combo.
 * Tokusou Sentai Dekaranger sometimes has Jasmine overtax her psychometry powers and become a Fainting Seer.

Tabletop Games

 * Champions. Normally, Endurance is used to fuel a character's power use. If a character runs out of Endurance, he can use Stun instead. If his Stun runs out, he falls unconscious.
 * Dungeons and Dragons: Deities and Demigods Cyclopedia (1980). If the Norse god Odin uses his powers to heal anyone, he falls asleep for 1 to 10 days.

Video Games

 * In Star Ocean 3, Fayt faints after activating his genetic Symbology ability Destruction for the first time. He also suffers some temporary memory loss from the event, indicating that it was especially psychologically traumatic.
 * In Dragon Age Origins, Wynne's plot power Vessel of the Spirit leaves her stunned and disoriented after every time she uses it. This effect is only alleviated after completing her personal sidequest.
 * Suikoden IV presents another rare male variant, which has Lazlo faint after each use of the Rune of Punishment,
 * Persona 3: the MC falls unconscious for a few days after summoning his Persona for the first time.

Webcomics

 * When Raezinus from Deverish Also demonstrates the portal spell and it becomes important to keep it open for a while, he eventually passes out from the strain of keeping the spell going for so long.
 * In The Cyantian Chronicles, the first time Darrik's energy manipulation abilities activate, he tosses a horse. It uses so much of he energy that he is left nearly unconscious.
 * In Spacetrawler, Eebs (or humans like Yuri with Eeb brain implants) will black out if they strain their telekinesis by moving objects that are too massive. Too much of this strain can outright kill them.
 * In Drow Tales, it's possible to blackout from overuse of mana. It actually happened to a weaker student in chapter 2. In later chapters Ariel and Chirinide exert themselves enough to become woozy after battle. Those who are more proficient in the mana arts are capable of killing themselves through exertion.

Western Animation

 * In the 1990s animated series, Jean does this after using her powers on Juggernaut to give him Laser-Guided Amnesia.
 * She does so again in a later episode, after showing Candra the truth of the Assassin's betrayal.
 * In Wolverine and The X-Men, Christy faints after using her earth powers to protect herself, her father, Wolverine, and Mystique from an explosion.
 * Avatar: The Last Airbender: The first time Aang enters the Avatar State in the pilot episode and several times in the first season before he gets used to it, he is visibly exhausted afterward. By Season Two, he's typically okay even if emotionally distressed.
 * Niko of Galaxy Rangers will occasionally overtax herself, draining her implant and her natural abilities and end up knocked out or barely conscious for a while. The upside is that if it gets to that point, she's probably just saved everyone's ass with it.

Real Life

 * Tom Jones allegedly fainted upon singing the long and loud final note in the theme song to Thunderball