A brief story arc on Ranma ˝ sees Ranma going from unnaturally strong uberhunk to a pathetic weakling who literally couldn't hurt a toddler, thanks to a moxibustion "attack" by Happosai. His many enemies (minus Ryoga) are happy to take advantage of this and beat the crap out of him as much as possible. Just as he's resigned himself to the situation, Ranma gets his strength back, and celebrates by giddily demolishing his house.
In the anime, Ranma had to go through special training to learn a move that would let him defeat Happosai without using any strength, but collecting energy from the surroundings and then releasing it. He learns it, but it takes him lots more to grab the scroll containing the cure for his condition, which Happosai himself had among his clothes.
Towards the end of the first arc in The Twelve Kingdoms, Youko fights her rival Yuuka without the Hinman that gives her her martial art skills in order to prove her who was the real Chosen One.
In Angel Sanctuary this is essentially what kills Kira after his healing abilities run completely dry. Not that Taking the Bullet didn't contribute to his demise.
After the first episode of Soukou no Strain, Sara has lost her family prestige and her ability to control her Strain, among other things. She resigns herself to a new name and becomes a trainee grunt pilot and scapegoat for her superiors... until she gets Emily.
In Ah! My Goddess, Belldandy has her "goddess license" (essentially, permission to use her magic abilities) suspended. This turns out to be more difficult than she expects because despite her immense magical power, her physical strength is on par with the normal human she appears to be (ie, not very much).
Happens to Francoise Arnoul aka 003 once in Cyborg 009. During an episode of the 2001 series she and the group are stuck in a high place with frequent sandstorms; this greatly decreases her enhanced senses, much to her despair.
In Mai-HiME, Natsuki temporarily loses her powers when she finds out that her mom attempted to sell her to the Searrs Foundation, rather than attempting to protect her. She gets better later, though.
Half-demon Inuyasha loses his powers and becomes fully human once a month, under the new moon. He hates it with a passion, and with good reason, since he ends up severely injured and/or in mortal danger almost every time. Luckily for him, his demon strength and super healing abilities always return just in time.
In Kanokon, Chizuru temporarily loses her powers (and her breasts) and has to cope without them. She never cares about her power being sealed, though. She just wants her breasts back.
Also Asuna due to her self-induced Laser-Guided Amnesia. The power was still there, but she had no idea it was, or how to use it right.
In a flashback, it is shown that Nagi had to enter a valley in which he couldn't use magic in order to save Arika. It didn't slow him down at all.
Happens more traditionally near the beginning of the manga, Negi places a Power Limiter on himself to avoid temptation of cheating on the exams. Of course he gets dragged along on an adventure anyway.
In the Chunin Exam arc of Naruto, after receiving Orochimaru's Curse Mark, Sasuke is unable to use his Sharingan or use any of his jutsus without suffering intense pain from the curse mark. Things get worse when he has to go first in the preliminaries and fights an opponent who can drain his chakra, which would potentially result in the curse mark activating. Fortunately, he manages to defeat his opponent with taijutsu alone (albeit with a move he had partly copied with his Sharingan a few days before). In the same arc, Naruto also gets a Five-Element Seal on the Nine-Tailed Fox's chakra (also courtesy of Orochimaru), which not only cut off his access to the Nine-Tails nigh-infinite supply of chakra, but also disrupted Naruto's own already shaky chakra control and thus making him a lot slower than usual at activating jutsu. Not helping was that Naruto's next opponent was really fast.
The title character of Sailor Moon has her Transformation Trinket stolen in one episode to prevent her interference. Even as a powerless 15 year old girl, she still shows up to the battle and manages to reclaim her pendant.
Minako also got Brought Down to Normal in the Super S manga, unable to transform into Sailor Venus. When Artemis temporarily reverted to his human shape to save her life, she not only got her powers back, but also obtained a Mid-Season Upgrade and became Super Sailor Venus.
This happened to all the Senshi in Super S, and the same happened to the Guardian Senshi after the battle with Metalia, they got better though, obviously. It's more obvious in Minako's case because she was the last one to recover and showed considerable angst about it.
Lina Inverse of Slayers ends up with her ridiculously powerful magic sealed for a good chunk of one of the NEXT story arcs.
Also in the first series Lina's powers fade for a few days because "It's that time of the month"
In Urusei Yatsura, one story arc featured a pair of yellow ribbons that when tied to Lum's horns sealed her powers. Later both Lum and Ten lost their powers when they lost their horns.
Happens a couple of times in D.Gray-Man. When Tyki dissolved Allen's arm, he got brought down not just to normal, but below it, since he now, well, only had one arm. It also happened to Lenalee after she pushed her Innocence too far in her fight with Eshi and went into a Heroic RROD that left her unable to use her legs properly, let alone synchronize with the Dark Boots.
And fangirls only remember the time the girl was affected with said phenomenon, not the boy. Pheh.
Claymore has Clare taking a preparation that suspends her demonic powers to avoid ecclesiastic prosecution.
Subverted to a degree in Fullmetal Alchemist. Ed sacrifices his power to perform alchemy in order to return Alphonse to his body. When Truth inquires how he will cope as a 'normal person', Ed confidently asserts that he has ALWAYS been a normal person, one who couldn't even save one little girl from being turned into a chimera.
It happens to Ling too, when Greed is removed from his body.
Pokémon: Best Wishes does this to Pikachu, after being attacked by a Zekrom (possibly to justify his routine depowering at the beginning of every new quest). Ash doesn't find out that Pikachu cannot use his signature Electric attacks until the poor thing gets curb stomped by a new trainer and his Grass-type starter. Pikachu gets his electricity restored in the next episode.
It happens to Pikachu in the beginning of the Advance Generation and DP arcs, as well. In Hoenn, Pikachu got strapped to a giant magnet which made its powers go out of control, and after it all he was reset. Sinnoh, however, didn't really have an explanation beyond him being exhausted.
In one chapter of Sgt. Frog, Koyuki is distraught because of her struggle to balance her ninja training with living like a normal junior-high girl, and uses an identity-sealing ninja art to forget her life as a ninja. It ultimately fails because her friend Natsumimisses the old Koyuki too much... good thing, too, as Natsumi was in the middle of being attacked by Keroro when the spell wears off.
Cardcaptor Sakura: Clow Reed wanted to lose most of his massive magical powers because he couldn't control his prophetic abilities, and thus conducted a massive Batman Gambit to make Sakura the new master of the cards. More details are explained in Tsubasa Reservoir Chronicle, as he was so powerful that he accidentally warped reality and kind of turned his girlfriend, Yuuko Ichihara, into a zombie.
In the second cours of Tiger & BunnyKotetsu starts to show signs of a rare condition that causes gradual power loss in a NEXT. An especially painful example, since it's drawn out in a way that makes it seem eerily similar to certain Real Life progressive diseases...
In HeartCatch Pretty Cure!, Yuri loses her powers as Cure Moonlight at the very beginning of the series. It isn't until 3/4ths of the way through the series that she gets a chance to regain those powers.
In Pretty Cure All Stars DX 3, the six teams at that point lose their powers and their partners defeating the Big Bad of the movie. The post-credits scene shows that they don't like the idea of being normal, but try to live on... until they all come back.
Habaek from The Bride Of The Water God give up his powers to be with So-ah and have a normal life together. Sadly, there's a problem within it...
Temporarily happens to Hazuki in Ojamajo Doremi, as punishment for using her magic to heal someone despite knowing it's a taboo. Later happens to all of the Ojamajo when they completely drain themselves to power to wake up Onpu from a Convenient Coma.
Occurs again at the end of Sharp when the girls are cursed by the Big Bad and once during The Movie When Pop's wish turns Doremi into a mouse; her tap is seen vanishing into light.
Occurs once again during the second Movie when a curse suppresses the girls' magic.
And finally happens againduring the penultimate episode when they have to choose between being Witches or normal girls. All of them -sans Hana- go with the latter.
In Fairy Tail, this happens to anyone from Earthland who goes to Edolas, due to the differing laws of magic, unless they take a magical medicine to counteract this. Notably, Natsu continues to be a Leeroy Jenkins, which nearly gets him and his friends killed several times.
Episode 8 of Kotoura-san has the local telepath Haruka lost her powers due to a cold. Both pros and cons of a missing her powers were explored, although many are mundane in nature ("I can finally watch movies for the first time as I'm not spoiled at the theatre" or the like). Her power returns in the stinger, in form of aFainting Seer.
A very important plot point in the semi-canon The King of Fighters: KYO manga. One of Kyo's basic motivations to fight was protecting his loved ones, as seen in a flashback he confided on his mother as a little boy, but as he grew up he gradually forgot it. At some point in the manga, Kyo started having self-doubts (like when a boy interested in his girlfriend Yuki beated him in a judo challange), which ended up catching with him and caused him to lose his Playing with Fire powers. This drove Kyo to close himself off his friends and have a big slump in his fighting skills... and almost to become Brainwashed and Crazy by Orochi. Once he remembers his real fighting motivation thanks to his father staging a mix of Hostage Situation and Batman Gambit, however, Kyo's beloved powers return.
This happens to Tiger and Mocchi in Monster Rancher's Post Script Season, because they became Mystery Discs following the battle with Muu, and so lost their special attacks. Tiger, having much pride in his strength before, takes this especially hard, and the teasing from Hare and Suezo does not help.
In the second season of Magic Knight Rayearth, Nova breaks Hikaru's magic sword, which strips her armor and cuts off her connection to her Mashin, rendering her unable to fight. It takes six episodes (during which her friends are captured by and escape from Cephiro's invaders) and a dangerous Journey to the Center of the Mind for Hikaru and Presea to repair it (and Hikaru's Heroic BSOD).
Done awesomely in Infinite Crisis, during the final battle against Superboy-Prime. Up to that point, Prime had defeated the Justice League, the Teen Titans, and the entire Green Lantern Corps and seemed utterly unstoppable. Then both Superman of Earth-One and Earth-Two show up with a plan. Moving at max speed, they fly Superboy-Prime through Krypton's red sun Rao and the kryptonite asteroid field that use to be Krypton before crash landing on Mogo. Afterwards, all three Supermen lose their powers and the fight for the fate of the universe is settled in a normal, human-level brawl.
After Infinite Crisis, Superman loses his powers for an entire year. 52, the series that covers this one-year gap, has him lying low, focusing on his job as a reporter with the Daily Planet. It turns out that, despite how he views Clark as his "real" personality, he really is bad at his life without Superman's powers. He is more timid and unsure of himself as a reporter, and Perry White actually moves to fire him after he lets the Planet get scooped on the large story of a new superhero. However, this revelation that he is letting his new status change how he lives his life, which he never thought would happen, galvanizes him to take dramatic action (i.e. jumping out the window) in order to attract the attention of the new hero and get the story. The writers explained that they included that scene because they wanted to make it clear that even without his powers he is still Superman, and his willingness to take extreme personal risks did not go away just because he can no longer take a bullet.
Also Krisis of the Krimson Kryptonite, where Mxyzptlk makes a chunk of plot device Kryptonite for Luthor that takes Superman's powers away. Notably Superman is never happy with this outcome unlike in the above example and tries to return to duty in powered armor. Also notable as the storyline where Clark proposes and Lois accepts his proposal.
In a seeming thematic tie-in Lois and Clark get married during a later instance of Superman losing his powers.
Superman also loses his powers permanently in World's Finest #178, and decides to try his hand as a Badass Normal hero - turns out he sucks at it (for one thing, he instinctively pulls his punches), but fortunately by the end of the follow-up story, Batman has promised to train him.
Pre-Crisis Superman also had another superhero life while in the bottle city of Kandor, where he has no powers. He becomes a BatmanExpy with Jimmy Olson, becoming Nightwing and Flamebird - Dick Grayson uses the former name in honor of Supes.
In another story, Superman discovered that he lost all of his powers every time he changed into his Clark Kent identity. He was faced with a choice of whether he wanted to live out his life as Superman or Clark. It was eventually revealed that an alien enemy had treated all of Clark Kent's clothes so they blocked the yellow sun radiation that gave Superman his powers.
In the Elseworlds series JLA: Act of God a strange wave of energy hits Earth causing heroes and villains alike to lose their superpowers. Some disappear into the woodwork while others reinvent themselves as Badass Normals in the Batman mold. However, if you watched one man's review of it, you'd learn the writers fucked up this execution royally.
Weirdly, this only applies if "normal" strictly means human. Superman and Martian Manhunter don't have any superpowers, technically speaking; their abilities are "normal" for their species. The same goes for Aquaman, except possibly for his ability to breathe air (which he does not lose).
A plot in the Justice League of America book saw six members of the League have their secret identities split off from their superhero selves. While Clark Kent, John Jones and Wally West saw it as a blessing, Bruce Wayne, Eel O'Brien and Kyle Rayner could barely hold it together. The split was mental as well as physical. For example, Plastic Man became an ineffective, gibbering fool, while his Eel O'Brien half reverted to the gangster he'd been before he got his powers. And Eel was doing a lot better than Bruce Wayne. The whole point was to show that the characters' hero and non-hero identities were both necessary to make up a complete person.
In the Justice Society storyline "Fatherland", every super-hero on Earth is robbed of their powers by super-villain Nazis and their darkness engine.
The M-Day, natch. Scarlet Witch, fed up with everything that went into and resulted from achieving mutant superiority, uses her power to declare "No more mutants." Thus, Earth goes back to what it was before, Bringing Down To Normal 90% of the mutants of the world (after all, looks like the X-Men are too popular to becomeBadass Normals). Some of them, like Blob and Chamber, end up in dire straits thanks to losing their mutant powers but not the body alterations that occurred because of them (notably, Jono almost dies thanks to his power having burned away his jaw, throat, and much of his chest when it first emerged).
Thor was brought down to mere mortal status for a while, and lost all of his fabled strength and power. Turns out that a 6 foot 5 tree trunk of a man with a big nigh-indestructible hammer is still someone you might want to avoid; he just went and beat the snot out of street-level villains for a while.
Red Devil/Eddie Bloomberg of the Teen Titans had his powers permanently taken by Brother Blood and was changed back into a human. This effectively got him out of his deal with Neron, though he still stayed with the team and one time donned his old power suit.
In "Johnny Saturn", at the end of issue eleven, the Utopian betrays the ideals that grant him his powers and kills a man from behind. At this point he loses all his powers.
Komodo in Avengers: The Initiative had her powers removed by SPIN technology after refusing to go along with HAMMER's sinister perversion of the Initiative. Note: without her powers Komodo doesn't have any legs. Thankfully, a "cure" of sorts was eventually fashioned and she's back in action.
In the Sonic The Hedgehog comics, the villain Dimitri spent centuries as the Physical God Enerjak, but eventually had his powers stolen by Mammoth Mogul via the Sword of Acorns; with his powers gone, Dimitri's age caught up to him, and he was eventually reduced to a shriveled head in a floating fish bowl.
Then, in a recent story taking place in an Alternate Universe, Knuckles (who had also become Enerjak) was stripped of his powers in the exact same way by his daughter.
Before this, mainstream Knuckles lost all of his power after he came Back from the Dead. Turns out they were suppressed, but it took him a good year in-series to fix that as the Dingos held Angel Island and the Master Emerald.
In issue 232, Ixis Naguas ends up restoring Bunnie's former flesh and blood limbs after crystalizing them an issue before, removing the abilities she had as a cyborg.
Marvel Comics loves this trope. Crowning Moment Of Awesome for Power Pack was when these otherwise ordinary pre-teens had to stop the very Snark who had stolen their powers — while shackled hand and foot!
In All Fall Down, this happens to every superhero and super villain. Permanently. Many of them are locked in denial for a long time about staying that way.
Evil SorcererDarkhell gave this treatment to his former rival Skroa in the french comic book Les Légendaires by testing the Stone of Jovenia (an artifact supposed to give youth back) on him, turning him back from a demonical garuda-like sorcerer to a regular small bird with no powers (though he retained his intelligence and the abilitie to talk). Skroa was then able to manipulate both an amnesic Darkhell and the heroes into leading him to the cure, allowing him to go back to his adult form with full power... only to loose them again in latter issues when the cure is taken away from him.;
Ironically enough, this was adverted with the protagonist; while they did get the same treatment from the Stone of Jovenia, they retained all their abilities and skills (probably because unlike Skroa, those were actual skills and experiences that weren't requiering an adult body).
protagonist Jadina was victim of this when Vangelis injected her a serum called "antimag", which had the proprertie to block magic. Since all of Jadina's powers were based on Magic, this left her, according to herself, "as weak as an unborn". This didn't prevent her from still being badass, however, as not only she didn't mope about it (she did has an Heroic BSOD, but it was because at this point things got so messed up she wasn't even sure to be the real Jadina anymore), but she was even still able to save her comrads from the All-mighty new villain Abyss, by kissing him so he would ingest the Antimag. By the end of the book, the Antimag's effect ceased and she got her powers back.
Deadpool recently lost his Healing Factor thanks to a serum Tombstone had engineered as part of his plot to get revenge on the Merc with a Mouth for the events of "Suicide Kings". This turned out to be a good thing for Deadpool — the events leading up to this help him shake off his Death Seeker nature and giving him a new will to live. The serum also restored his face.
While he couldn't lose all of his powers lest he ends up dying, Spider-Man is forced to drain a majority of Physical God Alpha's power after the kid recklessly battles Terminus, nearly killing Spidey's Aunt May and her husband (also J. Jonah Jameson's father) in the process.
Spider-Man also lost his powers shortly after Acts of Vengeance, via a plot of the Chameleon. In actuality, his powers were more suppressed than taken away. Initially, Peter wanted this, as it was one of those times he had grown weary of being Spider-Man. When he left the lab which held the machine responsible, he finds out quickly that his enhanced strength was a large reason he was able to web-swing, and almost got killed.
What Crux attempts to do to Starfire in Red Hood and the Outlaws. It didn't last for long, thanks to the Citadel's experiments on them.
Following Chaos War, Hercules burns out out of his godly powers and for the first time in his long, long life fully mortal without any god or demigod powers. He is so "weak" that he has to leave Olympus since he cannot survive around the other superpowerful gods. Of course "weak" is relative. He is still an extremely muscular man in top physical condition with centuries of combat training and experience. So he goes on to fight street level threats. He also steals some magical weapons from Olympus to help him fight more powerful foes.
After the events of Avengers vs. X-Men, Tony Stark is forced to give up the Extremis inside him after some of his more questionable actions.
In the 50th Anniversary issue of Daredevil set in a distant future, Matt Murdock's eyes are bathed in radioactive fluid when he saves New York. The result is him losing his radar sense.
From the same issue, Matt's future son eventually developed radar sense as a child. However, it was pretty traumatising, and Dr. Valeria Richards eventually cures him of it.
In the Fourth Movement of With Strings Attached, George has his ring stolen and Ringo cannot use his magic anywhere it matters, so they have to rescue the other two while effectively powerless.
Happens in the Naruto/Justice League crossover Connecting The Dots to Sasuke, who first loses an eye, then has his chakra taken away, and finally has half of the bones in his body broken as part of a Humiliation Conga.
The Immortal Game: This happens to Celestia twice. First, her powers are drained at the beginning by Titan in order to create Empyrean, and are returned to her by Twilight near the end of the story. During the subsequent fight with Titan, she gets cursed, which drains her power to ordinary pony levels; this thankfully wears off in time for the Final Battle.
Also ends up happening to Empyrean, Terra, and Titan himself, though only Terra lives for more than a few minutes afterwards.
Like wise in the Dark World Series of the 'Pony POV Series, this happens to Celestia and Luna by Discord draining their magic somehow, simultaneously turning them into foals and erasing Celestia's memory.
In Perfection Is Overrated, Yukino temporarily loses her Hime powers as a result of being hit with Shizune's Silencing Sigil, until the sigil is removed as a result of Shizune moving it to Mai. Yukino briefly ponders how her Hime powers have changed her, by forcing her to become stronger and more decisive, and how such changes are still in effect even though she has lost her power and expects to eventually lose it permanently.
This concept gets Deconstructed in Action Pack because it shows what someone with a healing ability would actually be like when Naruto watches his brother become groggy and practically unable to stay awake every month.
New Chance: To one Jonin's horror and Naruto and Hinata's shock, their Rasen no Mai is a weaponized version of this trope.
Twilight Sparkle and Rarity, when they cross into the land of the Fae in Into The Hedge.
Puella Arcana Somniator Madoka shows that showing up in the strange, unknown world will strip someone the powers of a Magical Girl. But surviving the Shadows in there and returning to reality will allow the person to unlock the potential and gain a Persona instead. This all happens after the Magical Girl turns into a Witch.
When Disney's Hercules surrenders his godlike powers for 24 hours in exchange for Megara's safety, one of the first things Hades does is punch him - hard. He then lampshades the trope by asking Herc how it feels to be just like everybody else.
In Spider-Man 2 Peter Parker loses his abilities due to a psychosomatic response to stress and burnout. While he enjoys the freedom from responsibility and the improvements upon his life, he realizes he should, and wants to, use his powers to help people. Once he's at peace with that decision, his powers return and he's back to saving the world. It was based on a famous storyline from the comic books.
In Superman II, the titular Last Son of Krypton gives up his super powers so that he can become romantically involved with Lois Lane. The holographic image of his dead mother explains the need for this vaguely as "If you wish to be with a mortal, you must become mortal", but those of us who've read Niven's Man of Steel, Woman of Kleenex know the real reason.
In The Mummy Imhotep is stripped of his powers after Evelyn reads from the Book of Amun-Ra turning him into a mortal man.
In the sequel, Imhotep (again resurrected) loses his powers when entering the pyramid in Am Sher, as Anubis wants him to fight the Scorpion King as a mortal.
The plot of X-Men: The Last Stand revolves around a serum created from a mutant that imposes this trope on any other mutant around him. Throughout the movie, several characters take the serum, either forcefully or willingly. Major characters include: Mystique, Rogue, and Magneto. In Magneto's case, it's revealed in The Stinger of The Wolverine that it may not be permanent.
There is an alternate scene where Rogue doesn't take the serum.
Hancock and other immortals like him suffers from this when they come into contact with their immortal mate. The loss of their powers allows them to decide to live a normal, mortal life and eventually die. All but Hancock and Mary have chosen this fate and died before the start of the film.
Raiden in Mortal Kombat: Annihilation willingly gives up his powers to help the heroes. He then spends most of the time getting his ass kicked.
Shir Khan, in the movie The Shadow, awakens after the climatic battle, wearing a straight-jacket in an asylum. When the doctor shows up, he tries to use his mind-controlling ability on him to get free. After this fails, the doctor mentions how the life-saving surgery that kept him alive had to remove a part of his brain, but only a part that "we never use". As Khan starts shouting how he "must be released! [He is] the direct descendant of Genghis Khan, destined to rule the world!", other patients start yelling that they are Napoleon, or George Washington...
The New Heroes begins with all of the superheroes and villains losing their powers and talks mainly about their children. It's further explored in the prequel series Superhuman.
The entire mechanism of Gail Carriger's Parasol Protectorate series is that the main character is a 'preternatural' who can take away the unnatural powers of both werewolves and vampires simply by touching them; these socially respected undead refer to preternaturals respectively as 'curse-breakers' and 'soul-suckers.'
Wide-scale involuntary rehumanification is the major plot element in the 2nd book in the series, Changeless
Happens to Richard during the last two books of the Sword of Truth series
This almost happens twice in David Eddings' Belgariad and does happen a third time in the followup, The Malloreon.
A sorcerous duel between Belgarath and Ctuchik leaves Belgarath weakened to the point that Polgara fears Belgarath may have lost his powers, or worse, had just enough to kill himself when he finally does use them.
Later on, Polgara believes she has given up her powers as a price to bring Durnik back to life and spends several weeks living as a normal human. It turns out to be self-deception.
In The Malloreon, the titular Seeress of Kell of the last book is stripped of her power to read the 'book of the heavens' (see into the future) in order to make the final decision between the two prophecies. She is, however, rewarded by the prophecy of light by eventually marrying Emperor Zakath.
Also done at the end of The Tamuli when Sparhawk renounces the title of Anakha and becomes a normal human as opposed to a god-killing being who exists outside of destiny.
Sparrowhawk in the later books of the Earthsea saga by Ursula K. Le Guin. It is even theorized by another character later that the ability to always pop up exactly where he was needed was actually his greater power, which he retained.
Former Knight Templar Cass/Sister Kassdy from Jack L. Chalker'sSoul Rider series agreed to give up all of her flux powers as part of becoming The Atoner. Ironically, this actually results in her becoming even more badass since the mechanism involved also makes her totally immune to those powers, tuning her into every flux manipulator's worst nightmare: a ferocious Mama Bear who cannot be injured—or even detected—by their powers. Given that most of the heroes are members of her extended family she is thus a person much to be feared. Fortunately for the bad guys the heroes tend to keep 'Grandma' in reserve until the absolutely last moment because she can't be healed by magic either.
At the start of The Day Watch, Alisa winds up completely depleting her magic in a conflict with the Night Watch, and has to spend time at a summer camp to replenish. She rather enjoys the challenge of seducing a man using only her appearance and words.
Who turns out to be a Light mage also suffering from this due to the same battle.
The Guardians, human-angel hybrids, can choose to Fall and become normal humans. They will still have highly diminished versions of their superpowers. The longer they spent as Guardians, the stronger those superpowers will be when they Fall. Many Guardians regarding Falling and being human as a retirement, after a long career of fighting evil.
In the Star Wars Expanded Universe, ysalamiri are creatures that "push back'' the Force for a space of a few meters each. Their planet of origin has so many that on that world, the Force is inaccessible, which makes Luke Skywalker have some difficulties when he's imprisoned on it and later has to go through a forest crowded with beasts that hunt Force-Sensitives.
"Welcome back to the world of mere mortals. Don't like it, do you? It's not easy to suddenly lose everything that once made you special, is it?"
Interestingly, in I, Jedi Corran Horn notices that when in a ysalamiri's field Luke seems younger and more optimistic, since not sensing the greater galaxy also means a reprieve from sensing his overwhelming responsibilities.
In The Waterless Sea by Kate Constable, second book in the Chanters of Tremaris series, the heroine Calwyn loses her powers of chantment after she tries to mend the "wounded land" of Merithuros. She doesn't like that very much. Actually, she says she'd have rather had her hands cut off. But she gets it back after she has a swim in a magic pool so she can then go on and becomes the Singer Of All Songs like she's supposed to.
In Anne Rice's Tale Of The Body Thief, Lestat (her favorite vampire) longs to be human again and make a deal with the con man to switch bodies. The rest of the book is how Lestat gets his real body back.
In the fourth book of the Ranger's Apprentice series Will is still suffering the after effects of drug addiction and has lost his Ranger conditioning.)
In Sergey Lukyanenko's Labyrinth of Reflections, one of the main plot points are a group of people in Deeptown called Divers, who can see programming holes and backdoors visually and are able to voluntarily break the illusion of full-body presence, whereas everyone else requires timers to kick them out or "exit menus" to allow their consciousness to go back to the real world. The protagonist is a Diver who, by the end, gains certain Neo-like abilities (except the book came out before the movie) after an encounter with a strange being (whose nature is left unexplained). The sequel starts with a Time Skip and the protagonist explaining that there significant changes have taken place in the Deep within the last few years. The kick-out timers are now mandatory, eliminating the need for Divers to pull people out. They also somehow lose their ability to see "holes", leaving cyberspace security work to hackers. The protagonist himself no longer has his powers that allow him to literally fly around the Deep and do anything he wants. He also can't connect to the Deep without the use of a computer (although it's not clear if this he actually had this ability). By the end of the second novel, he regains his powers by embracing them.
Nearly happens to the protagonist when he walks through the shield without knowing either what it does or that he has magic for it to affect. Luckily for him, his Love Interest was on hand with the antidote.
The House of Night: Happens to Aphrodite, and as of book 9 she has NOT gotten her vampyrism back. Still kept her visions, though, which was the one thing she could have happily gotten rid of.
Destined to Lead Kajiya is Brought Down to Normal - sort of, when her magic gives out after a particularly stressful assembly. She was banished from the very tribe she was supposed to lead. While her magic does not give out completely due to her being a magik, and thus favored by magic, she is still considerably weaker than before the assembly- making her magic the equivalent of other females.
Michael Vey has Nichelle, who has the power to painfully take away a Glow's power. When Michael manages to overload her power, Hatch deems her to have outlived her usefulness. While she still has her power, she was too scared of Michael to use it again, and many have stated that without other Glows around, her power is useless. In the second book, the Elgen invents a device called RESATs that replicate Nichelle's power, but in greater doses.
Gene Wolfe's Able of the High Heart (novels "Wizard" and "Knight") is effectively brought down to normal by promising not to use his higher powers as price for being able to return to Mythgarthr in pursuit of his true love. The grant of this dispensation is driven by concern for his happiness, not by admiration of true love; although God does move in curious ways.
The episodes '"Human Nature" and "Family of Blood" on Doctor Who feature the Doctor turned into a human via Applied Phlebotinum. He doesn't even remember being a Time Lord. Martha points out, "God, you're useless as a human!" and has to save his butt a few times.
While he's still a Time Lord in "The Lodger", he can't get to the TARDIS and is forced to live life normally (and in the right order.) Watching the Doctor cook and work in an office is adorably jarring.
In "The Eleventh Hour" he's left without his TARDIS or sonic screwdriver, his standby tools, and has to foil an impending alien invasion in about a half-hour using only his wits.
"Helpless" from Buffy the Vampire Slayer—a "test" called the Cruciamentum - a rite of passage to test the Slayer's intellect and wit - (induced by Buffy's mentor) at the command of the Watcher's Council. One she was never informed of or prepared for.
Aiko from Season 8 of Buffy, a Slayer who is full of squee when Buffy personally calls her after she is impressed the Japanese girl had killed a bunch of demons, is used as a test subject by vampires who want to depower the Slayers. They easily beat her to death and string her up as a warning/threat to Buffy.
Buffy, in particular, but it can be jarring to see everybody else being so...so normal in Season 9. Simone by proxy attempts to have her depowered and slain. Especially Willow, who has no powers at all.
Willow: "Without magic, I'm back to being part hacker, part hostage, while my superpeeps kick evil's butt."
On Angel, Angel becomes human for one episode by touching the blood of a particular demon. He feels his heartbeat for the first time in centuries and actually needs to eat. Buffy comes to town and they share a day as "normal" lovers. Except she is still a slayer who has to fight evil, and he can't help her. So Angel undoes it all by the end of the episode, and he is the only one to remember the entire thing.
There was also an episode where a villainess used a ray gun to take away Clark's powers and Lois ended up with them instead.
The same kryptonite thematic episode of Smallville.
Plus the one where a kid steals Clark's power with Kryptonite and thunder; when that same kid steals them again with more Kryptonite and a power generator; when he and Lex are trapped in a series of tunnels with just enough Kryptonite to make Clark normal; the episode with Perry White and the solar flare thingies (half the time); when Jor-El takes his powers at the start of the Zod arc; when Jor-El takes his powers at the end of the Veritas arc; when the clone of Zor-El tricks the clone of his mom into tricking him into taking the Blue Kryptonite ring; when Jor-El takes Kara's powers (and memories) for the vaguely plot-centric reason that her dad was evil; when they followed Brainiac into Krypton in the past; cloned Zod's Bad Future with the artificial red sun (and cloned Zod and his army of cloned Kryptonians have artificial powers, of course); and all the cloned Kryptonians count, too, though as clones they've technically never had powers; and... all in all, Smallville writers just love to take their character's powers away.
Eric Summers: Welcome back to being normal, Clark. Kinda sucks, doesn't it?
A comedic pseudo-example is an episode of Seinfeld where George finds himself getting very bad at lying.
Barney Miller, the "backup bionic guy" in The Six Million Dollar Man, had his bionics "throttled back" to normal human level after his initial appearance.
In one episode of Star Trek: Deep Space Nine, Odo has his shape-shifting abilities taken away by his people as a punishment for killing a fellow Changeling. Unusually for this trope, he does not get his abilities back until quite a few episodes later.
In Charmed there was an episode where Cole had to fully give in to his demon side in order to protect the girls which left him as a mindless beast for all of ten seconds before they used a spell to permanently remove his powers, leaving him mortal for a while and hating it. He then went on to assume the throne of the underworld and become the Source of all Evil in the world but hey, there was a difficult transition period. Where he went from there is difficult to follow. Cole sort of embodies Powers as Programs.
Additionally there are several times during the series where the sisters, while retaining their ability to cast spells, scry, and make potions, they lose their active powers, for example in "Power Outage" when a demon tricks them into using their active powers against each other in anger, breaking the Power of Three and removing their powers. Also in "Ordinary Witches", when an accident causes Phoebe and Piper's charmed powers to go to innocent bystanders. And when they are given the chance to experience not being witches as a reward for defeating the Source (twice). And several demons/evil witches who have stolen their powers over time.
Leo also loses his Whitelighter powers mid-series, after choosing his family over his responsibility as Whitelighter. Subverted in that, unlike Cole, he never regains his powers.
Pushing Daisies had a variant: Ned didn't lose his power, but decided to stop using it.
On the last episode of The Secret World of Alex Mack, Alex is given the antidote to the chemical GC-161, which originally caused her powers in the first place. We never find out if she uses it.
In one episode of Hustle, Mickey falls victim to a minor scam himself and loses his mojo as a result, going from suave and frightfully intelligent to an unlucky, bumbling idiot.
In an episode of Red Dwarf, Kryten is temporally brought down to normal when he is turned into a human being.
In the 1998 Merlin series, this happens to the gnome Frik, who loses his magic and becomes basically a strange-looking human. However, this might have worked to his advantage, as he shortly thereafter becomes a Badass Normal working for the heroes, and because he is no longer magical, he survives the end of magic instead of fading away as Mab does.
In the BBC Merlin, Merlin loses his magic for a while in the season 4 opener, after which he ended up passing out for a while. He was still in a bind when he woke up, but during the trip back to Camelot with Gwaine, he regains his power.
The season two opening of The Sentinel has Jim struggling with his heightened senses until they fade out altogether. He's later told in a vision that his experience so far has just been a taster and he needs to decide whether to continue as a Sentinel.
The third season opening reuses this trope. Jim accidentally shoots a security guard, blames his Sentinel senses and loses his abilities due to his guilt. He then has to go through with another vision to get them back and save the day.
The fate of every Super Sentai team, and at the beginning of the first episode of Kaizoku Sentai Gokaiger, after sacrificing their powers to defeat the invading Zangyack forces.
Bosses in Undercover Boss go deep undercover, work in the front lines working minimum wage jobs and sleep in cheap hotels.
Captain Jack Harkness discovers in Torchwood: Miracle Day that the healing factor and immortality he previously had is gone.
Chuck without the Intersect, which happens several times over the series.
Most recently, he's without it in Season 5. As with before, this doesn't stop Chuck from showing that he's far more than just a bunch of government secrets stored in his head.
On Heroes, Sylar spent all of Volume Two depowered after being infected with the Shanti virus. In Volume Three, the entire cast experiences this for a couple of episodes during a solar eclipse.
Earlier in Volume 3, Peter, the Physical God of the entire cast, loses his powers entirely... to his father!
Notably, the episode with the eclipse has Sylar and Elle realize how dangerous HRG can be with his superior training, when they're without their powers. As soon as HRG realizes that everyone has lost their powers, he grabs his sniper rifle and goes hunting.
Happens to Castiel from Supernatural several times over the series. In a Bad Future, he becomes human after the angels leave Earth for good and is a complete mess, indulging in drugs, booze, and orgies. Near the end of Season 5, he gradually loses his powers as he's cut off from Heaven and becomes much weaker, even needing to rest and sleep.
Cole experienced this in Tracker, thanks to an energy weapon made by one of Zin's guys. It nullified his Cirronian energy, and he was essentially human until Mel realized she could power him up again.
The episode of "Election" in Tower Prep features a disease that causes this.
Once Upon a Time: When the curse took over, all fairytale creatures that were nonhuman or magical became human and/or lost their magical power. For example, the Evil Queen can no longer use magic, Rumplestiltskin is returned to his human form (even regaining his limp and accent), the fairies are human nuns, and Red Riding Hood no longer transforms into a wolf every full moon.
In Moonlight, Mick is a Friendly Neighborhood Vampire who spends much of his time bemoaning the fact that he's a vampire. Finally, he's given the chance to (temporarily) turn back into a human... just in time to get his ass thoroughly kicked by an ancient vampire. Then again, even as a vampire, he couldn't have done much, as the guy is too good. The very next episode, he realizes just how badly he needs to be a vampire again and has Joseph re-turn him.
An episode of Mutant X has a New Mutant with a Healing Factor (which makes his Death Seeker personality a little ironic) working for GSA, when an epidemic starts that threatens to wipe out all New Mutants. He is forced by his boss to work with Adam (although ordered to shoot him as soon as he has the cure). When Adam extracts his DNA to use his Healing Factor to cure the disease, he inadvertantly removes this ability. The guy is happy to be able to injure his arm without it immediately healing... until the Big Bad realizes this and has him shot.
Season 3 of the American Being Human (Remake) sees self-loathing werewolf Josh as human after he kills his maker Ray. However, he soon becomes cursed after being scratched by purebred werewolf Liam in an attempt to save Aidan from his clutches. Similarly, Sally the ghost is brought back to life but she must not ever see anyone from her previous life or else they die of mysterious causes, and the insatiable hunger she feels is actually a precursor to her slow transformation into a zombie who needs freshly killed flesh (human preferred) to stall her encroaching decomposition.
The blood of a Grimm can strip a Hexenbiest (or a Zauberbiest) of his/her powers (in fact, they can't woge anymore), making them pretty much human, although they still have extensive knowledge of potions. Nick does this to Adalind by forcibly kissing her, knowing she will bite him to stop it and, in the process, ingest his blood. She later manages to restore her powers through a long and complicated (not to mention gross) ritual involving the death of another Hexenbiest, which also supercharges her unborn baby.
In the 3rd season finale, she returns the favor by pulling a Bed Trick on Nick and using a potion to make him normal.
On Friends, resident starker Chandler Bing is said to have a nubbin, a third nipple. Just after he has it removed, one of the gang makes an obvious joke that he misses saying. When he realizes this, he laments, "The source of my powers! Oh god, what have I done?"
In Don't Rest Your Head, if one of the Awake falls asleep, upon waking they lose all their powers until they stay awake at least as long as they slept... If they live long enough to wake up, that is. They'll be asleep for at least a full day, and from the moment they fall asleep to when their powers are restored, they act as a beacon attracting Nightmares to kill them or worse. The game is called Don't Rest Your Headfor a reason.
The 4e rendition of Forgotten Realms had the Spellplague do this to Elminster: once the mightiest archmage in the setting, with a direct access to the goddess of magic (his on/off lover) and an essentially limitless lifespan, reduced to a near-powerless tired old man thanks to the ravaging of the Weave and the murder of Mystara.
Happens to the Toa Nuva in BIONICLE after the Bohrok-Kal steal their powers.
And then again to Tahu Nuva in the final battle, reverting him to his original design from 2001. It was necessary for him to use the Golden Armor.
Prototype: Well, almost normal, anyway. About halfway through, you get infected with a parasite that robs you of all your powers, save disguises and your baseline abilities. On the plus side, the upgrades you get for removing the parasite are worth the wait.
At the beginning of God of War 2 & 3, you start off with some of the magic attacks from the previous game but are soon relieved of them.
Slight subversion in Kingdom Hearts when Riku steals Sora's keyblade in Hollow Bastion. It's subverted in that, while Sora is normal for all intents and purposes during this time and forced to fight with a wooden sword, it is not shown as a good thing in the slightest, as only the keyblade can defeat The Heartless and keep the universe from unraveling.
Iori Yagami as of KOF XII & XIII. He can still tear you a new asshole with his bare hands.
Neverwinter Nights: Hordes of the Underdark has an optional bonus dungeon in chapter 2 that is under the effect of an ancient artifact that blocks all magic. Without your bags of holding, magic weapons, potions, spells, and Rings of Protection your character will have trouble dealing even with the normal monstrous spiders around the entrance, let alone the Belibith further in. And good luck if you're playing an archer and neglected to buy ammunition since you've got that cool unlimited-electricity-damage-arrows shortbow...
Sonic Labyrinth has Eggman sealing away Sonic's speed in the form of very heavy shoes. Sonic can still Spin Dash, though.
In Disgaea 4, the main character had this happen to him because he refuses to break a promise he made not to drink human blood. Slightly subverted in that, thanks to The Power Of Sardines, he is still stronger than most of the enemies thrown his way. "Normal", in Hades, is still pretty badass.
Once is actually done humorously in the Null Magic Hall to the opponent you are supposed to fight, he is a magician, but due to the rules of the Null Magic Hall; magic cannot be used. However Techs and Ryu's Transformations can.
Another is Fighting the Elder Dragon, Ryu cannot transform due to specific wards placed in the room to prevent Myria from spying.
In the aftermath of the Final Battle of World of WarcraftCataclysmthe Dragon Aspects lose their immortality after channeling their powers through the Dragon Soul to slay Deathwing for good.
Shantae: Risky's Revenge ended with Risky stealing Shantae's genie powers. Shantae and the Pirate's Curse has Shantae adjusting to life as a non-genie, and fighting to get her magic back.
Her hair changes to black because it is a side effect of burning out magically.
Gregory Deegan suffers a pretty brutal version of this in Dominic Deegan in the "Built to Resist" arc. TIM, having recently escaped from another dimension and packing Lovecraftian Superpowers, rips out Gregory's white magic. And this is just one part of the Break the Cutie treatment Greg gets in this arc...especially since, unlike most examples, his depowering turns out to be permanent.
Dominic himself loses his Second Sight, as part of The Finale.
Jade Harley of Homestuck started off with her Dream Self already awake, which gave her a huge advantage over the other three kid protagonists. She was so far ahead that quite a few people in the fandom considered her a Mary Sue character. That quickly changed however, when her Dream Self got killed and she lost the ability to see future events, along with all her cool stuff in her house. To make matters worse, since Jade was asleep for so much of the storyline, she was actually behind now when compared to the other protagonists' progress in Sburb. She was brought down to sub-normal.
Of course, she caught up to everyone else fairly quickly, then went God-Tier in [S] Cascade, putting her on even ground with the other kids.
The title character of Princess Pi once lost her throne, and later her invincibility, as a result of a bratty little girl using a genie to help herself become the ruler.
Apparently happening to Abel in Dan and Mab's Furry Adventures as a consequence of not feeding on emotions. Aaryana believes that this is why Abel is able to dream (something Cubi normally can't do) and why he needs to eat and sleep. His Being half is becoming dominant since he is starving his Cubi half.
Also attempted in Start of Darkness, when Lirian inflicts Xykon with a disease that saps his magic. Unfortunately, his minions have just enough resources to allow him to undergo the Emergency Transformation into a disease-immune lich.
Happening to Richard and his townspeople in Looking for Group. As a consequence of being less of a figurative monster, Richard is slowly becoming human again. Since the people of his village are linked to him, they too are becoming human. Maikos compares this to dying since they are no longer immortal pseudo-undead beings. They can age, get sick, starve, and die just like any other human.
The Global Guardians PBEM Universe: During the storyline in which invulnerable, untouchable hero The Shield temporarily lost his power to surround himself with an impenetrable force field, he freaked out and ended up temporarily institutionalized because of his pure, unadulterated fear of being hurt.
The Monster Girl Encyclopedia has a Cute Monster Girl version of a doppelganger. A girl in a black dress, she can read the mind of a man who was rejected by the woman he loved, and use her shapeshifting ability to become the ideal version of said woman. When she approaches him, the man can't help but love her as well. However, should the man see the doppelganger in her true form, and love her as she is, then she will lose the shapeshifting ability. Not that she needs it anymore though.
In Phaeton the Bounds children all burn out their powers during the mission to Japan. They still haven't been restored.
Superman: The Animated Series had Luminous block off yellow sunlight, sapping Superman's power source. Clark hated it, as not only couldn't he do any super heroics, he finally had to use iodine on his wounds and got to experience what a pulled muscle felt like.
In another episode, Mr. Mxyzptlk's powers are removed for misusing them.
In another episode, Supergirl is trapped in Skartaris, which likewise has a red sun, depowering her considerably. However, instead of moping around, she quickly confirms that her powers indeed don't work and adopts new ways of being awesome, namely, by being a Little MissDeterminator.
Happens to Green Lantern a couple of times during the series as well when his ring is drained, broken, or taken away. But since John was a member of the Marine Corps before getting his ring, he can and will kick butt without it, if not as effectively.
Lloyd in Space, "Francine's Power Trip": Telekinetic Francine has a cold and has lost use of her powers, usually used to annoy Lloyd.
Monster Allergy had Zick losing his powers to Magnacat after being trapped in a container that absorbs his powers ("The Devourer"). Later, he gets them back after he sees his father in danger ("The Last Tamer").
There's one episode of Winx Club where, as punishment for sneaking out of the school and causing trouble, the principal strips the main characters of their powers , forcing them to stop a monster using brooms and soap.
Winx Club also did a variation on this as Story Arc later in season 1, with Bloom losing her "Dragon Flame" powers to the Trix. Several episodes later, she is under a lake with her sister/secret guardian Daphne, and it's revealed that Bloom's powers never left her (even though all signs pointed otherwise, starting with the fact that she was stuck in her regular form all these episodes), but her Heroic BSOD blocked her from summoning them. Once she stops moping, she gets her powers back.
The Trix and Ancestral Witches in Magical Adventure do this to every fairy in the Magic Dimension to give themselves exclusive rights to magic-using.
"Night of the Living Grim": Grim contracts a bizarre magical disease, "Encroaching Doom Syndrome", that results in him turning into a mortal human. He goes back to being The Grim Reaper when the living slime creature his sickness created apparently eats off his flesh.
There was also an episode were Mandy lost her nerve (as in a little Anthropomorphic Personification of her attitude living her head) and it moves to Billy's head. This downgrades her from Heroic Comedic Sociopath to meek little girl and Billy up to a bully (though he's still stupid). She later decides she doesn't need the nerve and returns to her usual state while making the nerve vacate Billy's brain.
In "Gwen 10", the What If? episode of Ben 10, Ben wakes up without the Omnitrix, but remembering the series so far. Upon realizing that it's the day he got the Omnitrix, he tries to get it back... And fails. He kinda mopes for the rest of the episode, but nothing else is shown of how it would have gone from there; it's a one-shot "What if?" style episode, complete with Shout-Out at the end. A more straight version of this was the season two finale, where Ben loses the Omnitrix after finally mastering its abilities, resulting in him having fight both of the show's major villains (up to this point in the franchise, anyway) without it. The episode ends with him and his cousin winning the battle with limited use of superpowers, and Ben regaining the Omnitrix, albeit unable to access the device's full abilities once more.
At times the whole Ben 10 show seemed to play with the idea of losing powers. It was a story formula, he would use his alien powers, beat the tar out of several guys, then the true big bad would show up, and the Omnitrix would be out of juice, Ben would then have to use his wits, creativity, and family to hold them off till he could juice up again. Presumably, they got tired of that because in "Ben 10: Alien Force" he never runs out of juice and changes from form to form at will.
In Danny Phantom, thanks in part to Sam's unassuming wish, Danny ends up an Average Joe without his ghost powers until she wishes it back.
In an episode of W.I.T.C.H., Cedric's attempt to track down Elyon resulted in the Guardians losing their powers (It Makes Sense in Context). Unfortunately, they were stuck in their altered forms.
Another episode had Cornelia accidentally take up the others' powers, turning her into a super-Guardian, forcing Will, Irma, Taranee and Hay Lin to figure out how to keep fighting without their powers.
"Power Outage" from Static Shock. Every Bang-Baby in the city, including Static and Gear, gradually lose their abilities. Most of them like it that way. Static and Gear are restored at the end — they have to be, "Future Shock" confirms that they're members of the Justice League in forty years — but the rest of the Bang-Babies are implied to be permanently depowered. This was the last episode.
In the Men In Black: The Series episode "The Out to Pasture Syndrome", in a climactic battle with Alpha, Jay turns one of his weapons on him and destroys all his alien appendages, reducing him to a (horribly emaciated) human. He is then locked in a highly-advanced prison cell.
Alpha: Go on, Zed. Destroy me. Do it!
Zed: No. You're a mere mortal now. You'll be punished like one.
Of course, this comes back to bite MiB in the butt in the next season when Alpha escapes, gains new robotic appendages and helps the Ixions attempt to invade Earth.
While a hyper-evolved worm is by no means "normal", there was an episode of Earthworm Jim where Jim's super-suit was replaced with one that only gave him strength comparable to an ordinary person. Or as Professor Monkey-For-A-Head found out the hard way, "an ordinary, really big person".
Gladstone:I don't believe it! I've lost my luck! No food... no money... gasp I'll have to get a job like normal people!!
Raiden of Mortal Kombat: Defenders of the Realm loses his godly powers during an episode involving a magical orb. He's still badass thanks to the fact that he has been fighting for thousands of years.
During the episode, Raiden does show distress and unease at losing his powers, explaining that for him, being a Physical Godis normal.
The Adventures of the Galaxy Rangers episode "The Power Within". A slight subversion as it was demonstrated here that the Series 5 implants don't give the Rangers their abilities, just enhance what's already there. Niko could still sense the hunter on their trail and misdirect them, and Doc was still able to hack Nimrod's computer - it just wasn't as fast or as flashy as what they could do with a badge push. Of course, one scene could be read as the Series 5 implant curbing Shane's ability to use his abilities, but seeing as he is the last of a failed super soldier experiment, that could have been deliberate.
One episode of Batman Beyond had a computer virus infect Terry's batman-suit-mini-Power Armor thing, forcing him to go it with just a utility belt and domino mask rather than flight, invisibility, super strength, etc. Turns out he picked up a few of the bat-skills from Bruce after all.
ReBoot. Part of the plot for My Two Bobs involved Bob bringing himself down to normal in order to be more "original" like the other Bob. Hexadecimal was also brought down to normal earlier when a viral scan reformatted her into a Sprite.
Generator Rex delivers this to series Big Bad Van Kliess. After bringing him back from the dead (long story) Rex agrees to join him if he lets his friends go. He then shakes Van Kliess's hand... and promptly cures him, sapping him of his powers, and reverting him back to a normal human. Needless to say, Van Kliess quickly makes a hasty retreat courtesy of Back from the Dead Breach
Max Steel did this near the end of the first series. After an argument between Max and Rachel about Max relying on his powers over his training, he (naturally) loses them for the episode. However, he hates this fact and is all too willing to get his powers back.
And in the finale, Aang uses Spiritbending to take away Ozai's ability to firebend, neutralising the threat he poses to the world without breaking Aang's Thou Shalt Not Kill policy.
The Darkwing Duck episode "Duck Blind" has Darkwing lose his sight after Megavolt overloads numerous lightbulbs. After a period of failed crimefighting and later self-pity, he manages to overcome the initial loss by utilizing his other four senses, and smashes the light in Megavolt's lair bringing the fight to equal footing in darkness. Status Quo Is God is followed by an accidental shock after the fight restoring his sight.
It should be noted that both times Sonic doesn't actually lose his speed. He's just put into a position where he can't use it. His sneakers are designed to protect his feet from the intense friction running at the speed of sound would create.
In the pilot, Princess Luna undergoes this after her defeat as Nightmare Moon.
Discord can take away pegasus wings and unicorn horns on a whim, which he demonstrates on the mane cast in the season 2 opener.
In the season four premiere, the Mane Six is forced to give up the Elements of Harmony to stop Everfree Forest from growing out of control. On the plus side, doing so revealed a special chest that may be able to get them back. If they can find six special keys.
Twilight's Kingdom Part 2: Celestia, Luna and Cadance when they transfer all their magic to Twilight, and Discord goes through this when Tirek drains him of his magic. This also happens to Twilight when she surrenders hers and the Princesses' power to Tirek. The Mane Six return the favor after unlocking the aforementioned Rainbow Power chest.
In the movie My Little Pony Equestria Girls, Twilight loses her magic when she enters the human world, and also can't depend on her encylopedic knowledge (since she knows nothing about the world she is in). As an ordinary human girl, she has to accomplish her task using only her leadership skills and her knack for repairing broken friendships.
At the end, after Twilight leaves with the crown and the portal closes, the Humane Five revert from Magical Girls to normal humans.
Happens in a direct-to-DVD/Netflix episode of The Avengers: Earth's Mightiest Heroes, specifically to Captain America, The Mighty Thor, and Iron Man due to a magic spell. Captain America goes back to his scrawny, pre-Super Serum self, Iron Man is in his prototype armor (and doesn't know how to use it), and Thor becomes a mortal (and promptly gets his leg broken, in homage to the injured leg of Donald Blake, his comic incarnation's non-powered human form for some time).
Subverted in Team Umizoomi, Where The Shape Bandit takes Geo's Shape belt so he can use the shapes build a house. Geo still has his powers, He just builds necessary items out of toys, food, and toiletries instead.
Similar to the Darkwing Duck episode above, an episode of Batman: The Animated Series had Batman rendered blind after an explosion. He circumvents this at first by devising a helmet that would mimic a bat's sonar, but, when the Batplane crashes attempting to catch the Penguin, he accidentally snaps the wiring and is forced to capture the Penguin blind. However, it just makes him even more scarier, since he can now catch criminals blinded, but as Status Quo Is God, he's back to normal at the end of the episode.
An episode of Fantastic Four, the team lose their powers after an nuclear explosion goes off. Ben's overjoyed at being human again, but Reed is out to prove that he isn't useless and makes a set of gear to replicate their powers. They end up regaining their powers confronting Doom with the aid of Daredevil.
The Legend of Korra: The Big Bad of season 1, Amon, has the ability to take a person's bending powers away. In the Series Faux Nale, he eventually does it to Korra herself, but the trauma also unlocks her airbending, which she had been unable to use until then. Later she gains the Avatar State, restoring her own bending, and Aang teaches her to use spiritbending to restore everyone else's.
Part 1 of Transformers Animated's Christmas special sees the Autobots suddenly wake up in their factory base as ordinary humans. They spend some time trying to adapt to their new, weaker bodies and figure just what happened. Ultimately, the whole scenario was revealed to be a virtual world generated by Soundwave so that he could keep their conscious minds occupied while he brainwashed them into becoming Decepticons.
Has happened to The Powerpuff Girls a few times, in episodes such as "Slumbering with the Enemy" and "See Me, Feel Me Gnomey."
People that are highly dependent on social networking sites and mobile gadgets can feel like this when deprived of them. Although, since this is now the normal way of life for much of the planet, it may even feel like a case of "brought down to subnormal," depending on the person.
In countries where an official is elected for a certain term, once that amount of time runs out, they are once again a civilian. Though, depending on the office they held, they may be given special protection for the rest of their lives.