Near the end of the Stone Ocean arc of Jo Jos Bizarre Adventure, EnricoPucci achieves godlike status as he has gained the ability to speed up time and move the universe towards destruction and recreation. Pucci has already killed off most of the heroes, and all that's left is Tagalong Kid Emporio Alnino. Pucci stops the universal reset just short of a full cycle in order to catch Emporio at the one moment they were both in the same location — the Green Dolphin Street prison — in order to kill him. Pucci thinks this will be easy enough, seeing as how Emporio has one of the weakest abilities in the entire series, but unknownst to him, Emporio borrowed one of his fallen friend's abilities, and just as Pucci is in the perfect position to kill Emporio, Emporio is in the perfect position to kill Pucci. The kid surprises him with a weather-changing ability and uses it to poison him with fatal levels of oxygen.
Kars of the Battle Tendency arc gets this as well. Having just become the Ultimate Life Form, he's Nigh Invulnerable, capable of regeneration, transformation, and is immune to both the sun and Ripple power. However, his decision to give Joseph Joestar an ironic death via Ripple massively comes back to bite him, as Jojo uses the Red Stone of Aja - the same MacGuffin which gave Kars immortality to begin with - to reflect it; Kars' is launched into space by his own power, where his Adaptive Ability generates a shell that prevents him from dying.
To add insult to the injury, Joseph gets one of his hands sliced off just as Kars emerges from the volcano. While Kars tries to fly away and leave Joseph out there to die, that same hand gets flung into Kars, knocking him out of the atmosphere into outer space before Kars could react in time and escape.
In Stardust Crusaders, Hol Horse's Stand takes the form of a gun that fires bullets who's path he can control. On two occasions, this has led to Hol Horse accidentally shooting himself with his own bullets.
Okuyasu from Part 4 has the stand ability to erase anything by swiping it with his stand's right hand, causing anything surrounding the empty space to close in and fill it in. He'll occasionally use this to teleport himself forward a few feet or pull things towards him, but the first time he demonstrates this use by pulling Josuke towards him, he also accidentally pulls forward a nearby potted plant, which hits him in the head and knocks him out.
Also from Part 4, Rohan is a mangaka with the ability to open up anyone who looks at his manga like a book. On top of incapacitating the victim, he can also read their minds, which is how he comes to discover Josuke's Berserk Button about people insulting his hair from another character. When Josuke figures out what causes the Stand to affect him, he advances on Rohan with his eyes closed, and though Rohan pushing his Berserk Button does finally get him to open his eyes, he's then too blinded by rage to actually look at the manga he's holding out, and Rohan quickly gets clobbered.
Digimon Savers: The Big Bad Kurata committed genocide, created collateral damage to to take over the world in the mean time he sucked in void bending devices, so what does he do when he gets defeated? He activates a huge explosion that causes the Digital World to crash into Earth, and he disappears into a light while doing it. This action also is the final straw for the Final Boss.
In Digimon Xros Wars, Neptunemon is killed by his own trident. It has a homing ability, and Shoutmon X4 uses that to his advantage and jumps behind Neptunemon, causing the trident to have to pierce through him to reach its target.
Big Bad Dr. Hell designed a Mechanical Beast (Spartan K5) resembled a Gladiator... but it was a pacifist refused attacking unless provoked. Baron Ashura requested testing it against Mazinger Z anyway, but Kouji actually befriended it. Enraged, Ashura ordered several Iron Masks putting a time bomb on Spartan K5 to blowing it up. Later, the Mechanical Beast was accidentally goaded into attacking Mazinger Z and UTTERLY BEAT THE CRAP OUT OF IT. Right when it was about of delivering the final blow, the bomb went off. Kouji and his friends got sad. Hell and Ashura got angry.
A nearly literal example in another episode. Kouji was fighting the Mechanical Beast Glossam X2 in a an underwater battle. Glossam shot a pair of torpedoes at Mazinger. Mazinger grabbed them and threw them back, blowing Glossam up.
In episode 27, Ashura captures Aphrodite A and scans it in order to learn how building a photong engine. He hands over the records to an Iron Mask and commands him go and hand them out to Dr. Hell. Though, a Kikaiju -that had been deployed by Ashura to delay Mazinger Z- is returning to base right on that moment, and steps on the Iron Mask, killing him and destroying the information they had obtained.
UFO Robo Grendizer: The Vegans managed to make huge technological breakthroughs by exploiting ores of the material radioactive known as Vegatron. However, it led to his planet becoming unstable, forcing them to find new worlds to colonize. The vegatron bombs they rained upon Fleed scorched the Fleedian army to ashes, but they also turned the planet they intended to colonize on a radioactive wasteland. And finally, Vegatron radiation destroyed their homeworld and rendered their Moon Space Base -their last safe haven- inhabitable.
Soukou no Strain kills off Medlock by having Ralph override her ship and order her own killer robots to tear her apart. The real irony is that she had recently turned good, and the good guys assumed she got out safely like they did and didn't think anything of looking for her...
In contrast with the manga, many Sailor Moon anime characters died this way (in fact, the protagonists themselves rarely kill anyone, except for monsters-of-the-week and Big Bads) — at least when they were not offed by the Big Badfor their constant failures, betrayed by their peers, or redeemed. Malachite/Kunzite died of his own reflected attack (though Sailor Moon still qualifies for that kill by reflecting it); Mimet/Mimete died when she used a machine built by Eugeal/Eudial, whom she killed; Telulu/Tellu was blown up by the giant plant she summoned; Byruit/Viluy had her Nanomachines turn against her and "erase" her; Cyprin/Cyprine and Petirol/Ptilol (regarded as one person) were tricked into blasting each other, Rubeus is killed when he blows up his ship, and Sailor Lead Crow was sucked into the black hole that she tried to use against Sailor Moon, though only because her black hole device was sabotaged by her sociopathic teammate, Tin Nyanko.
In the second season of Yu-Gi-Oh!, when Yugi dueled Marik's mind-slave Strings, the only way he was able to beat his invincible card setup was to use it to his own advantage so that his monster would be destroyed and regenerated an infinite number of times within a single turn, and due to one of the effects Marik had on the field, Strings was forced to keep drawing cards from his deck every time the monster regenerated, until he ran out of cards and lost the duel by default.
When Yugi defeated Duke Devlin at Dungeon Dice Monsters, it was, in a way, Duke's fault; he had inadvertently designed the DDM version of Dark Magician, Yugi's favorite monster, incredibly powerful, with abilities that made Yugi able to use it with almost as much synergy as he did in Duel Monsters. (Yugi could not help but thank him for making such an accurate version of his favorite card before he delivered the winning blow.)
In the Virtual World arc, the Quirky Miniboss Squad all suffer a defeat this way. Oshita insults Yugi's Kuriboh, and loses because of its effects, Otaki laughs at Black Magician Girl for being useless without her master, so Anzu Summons it, Oka, a smug lawyer, falls for an obvious bluff, Ota, who viewed Shizuka as the weak link, loses to her St. Joan, Daimon, who viewed himself as superior to Kaiba, loses when Kaiba Summons a card strong enough to attack his Kill Sat, and when merged together, they view Jounouchi as The Load to Yugi, only to have Jounouchi's cards be instrumental to victory.
In the second season of Yu-Gi-Oh! GX, Judai dueled X, a Pro Duelist who used a Mill Deck; Judai won by decking him out. X was a very unpleasant person (even Edo, who witnessed the duel, didn't like him), so this was sort of poetic justice. (Of course, Judai does this using one of his Neo-Spacians, and a common theme with his duels is that the villains never understand how they work and never take them into consideration. Even the most Crazy-Prepared villain can never prepare for something he knows nothing about.)
Yu-Gi-Oh! 5Ds plays it in another angle. While locked in the Facility, Yusei is forced into a duel with the head jailer. His Iron Chain strategy is to exhaust the opponent's deck, but Yusei reveals that his last two cards (from a deck all cobbled together from other jailed duelists) actually depended on a high graveyard count, and he wins the duel with them.
There's an example before that, way back in episode two. Yusei duels a guy who uses Insect cards, and had a Spell Card on the field (Ant Lion's Vengeance/Retribution of the Ant Lion) that damages a player whenever their monster goes to the Graveyard. Yusei pulls off a combo that destroys all three of his opponent's monsters, and lets his own Spell card do the rest. (Given that the guy purposely destroys one of his own Insects earlier in the duel to use its effect, he's obviously not entirely clear on how his own card works; long story short, he was an Ineffectual Sympathetic Villain, more or less.)
The Yu-Gi-Oh! Tenth Anniversary Movie Paradox's Sin World set does him in. Paradox's set essentially hinged on weakening his opponents' monsters enough so that his overpowered beasts could curbstomp the Dream Team of Yami Yugi, Judai and Yusei, essentially killing them. Yami Yugi starts the unraveling when he takes back Yusei's stolen Stardust Dragon and it was more or less a defensive waiting game, tanking attacks and rescuing fallen monsters until the time was right to flatten Paradox and save all of time.
Minor example in Yu Gi Oh ZEXAL (no real wagers were involved) in the episode where Rio demanded a duel from her brother, Shark. Rio tried to win by using a Field Spell that benefitted Water-Attribute monsters and Xyz monsters, and used them to gain an advantage for a turn, summoning a powerful Xyz called Ice Princess Zereort. Unfortunately, she seemed to forget that her brother also specialized in Water-Attribute Xyzs, and was able to use the Field Spell to summon a far more powerful one called Shark Caesar, which was able to wipe her out.
In Yu-Gi-Oh! ARC-V, Shingo steals two of Yuya's cards and gives him the weak monster Block Spider as an insult, saying it's nothing but trash. When they duel, Block Spider deals the final attack to Shingo.
In Mahou Sensei Negima!, Negi used the same power Rakan tried to use on him. It failed to keep him down for the count though.
A good example of the monster variety: Babidi is done in by Majin Buu (while Buu was his father's creation, not his own, he intentionally released him).
Frieza was cut in half by his own attack (he even lampshades it) which led to his first demise (though he got better later on).
It's also stated the Frieza's the one who created the Super Saiyan legend - when he destroyed Planet Vegeta, he ended up sending Bardock to the planet's past, where Frieza's ancestor confronts him. Their fight leads to Bardock becoming a Super Saiyan and killing him; with the ancestor's dying breath, warns them of the golden-haired warrior.
Once in a movie and once in the series, Garlic Jr. opens a hole to the Dead Zone, an empty dimension, to try to capture our heroes. No points for guessing what happens both times. Even worse, being immortal, the Dead Zone is the ONLY known thing which could potentially defeat him. And he let it be used against himself TWICE. He was asking for it, really.
Dr. Gero, thrice (in the "real" timeline and in the two future timelines).
And in the original Dragon Ball, Tao Pai Pai got blown up by his own grenade, as Goku kicked it back to him (although like Frieza, he made an Unexplained Recovery later on. In both cases, they came back as cyborgs.)
In Dragon Ball GT, Cell and Frieza, while fighting Goku in Hell, trap him in Hell's freezing depths. Unfortunately for them, ice down there is actually sentient, and the living Goku is too warm for them to freeze him. Cell and Frieza, being dead, are naturally far more vulnerable.
In Rurouni Kenshin the puppetmaster Gein surrounds Aoshi with oil soaked wires that he lights causing a forest fire. Aoshi uses Onmyô Hasshi to hit Gein with a Kodachi, and reveals that he has tied a wire Gein had left during the battle. Gein begs him not to kill him but Aoshi pulls Gein into the fire Gein had set himself killing him. Aoshi escapes the fire by using a hole he had dug earlier.
In an early episode of Fullmetal Alchemist, Ed does battle with an alchemist who transmutes a sword and is later impaled by it. Needless to say, he doesn't get better.
This also shows up much later in the original manga, when one of the generals awakens the Mannequin Soldiers so they can take back the city from Mustang/Armstrong's insurrection. They promptly eat him.
The main villains of both series also fall victim to this. In the first anime, Dante, tired of Gluttony's whining over the loss of Lust, transmutes his reason away and turns him into a mindless monster. She is later killed by him because he's gone berserk. In the manga, Pride eating Kimblee after the latter's near-death proves his downfall, when Kimblee's soul ends up distracting him at a crucial moment and enables Edward to destroy his Philosopher's Stone (something Pride had never even considered, because he had assumed it was impossible for any soul he consumes to maintain its individuality). Also, Father's attempt to absorb Greed for his Philosopher's Stone also backfires when Greed uses the connection between them to use his Homunculus power on Father, turning his body to charcoal and leaving him vulnerable.
Gato, the gangster who hired Zabuza and Haku, gets slaughtered by Zabuza.
Zaku ended up having his arms blown up by his own air tubes (implants which let him perform sonic and air pressure attacks) after Shino snuck some of his bugs up into them, clogging them.
Sasori the puppet master gets impaled by his first creations: puppets made to look like his own parents, wielded by his own grandmother. She suggests that the human heart left in him made him hesitate upon seeing them rushing toward him, rather than dodge it.
And after he was resurrected, he was defeated again by getting trapped in his previous puppet body, controlled by Kankuro, the same guy who he EASILY defeated before.
In filler news, two of the three Jannin from the Land of Greens arc were whacked by having their own powers used against them. The first was Gentle Fist'd by Hinata in a way that smothers him in his own magnetic powder, effectively making his jutsu into a ball of suck by breaking the "off" switch; and the second had his ice-crystal death ray reflected back at him by Naruto's headband.
The third was also defeated because he was crushed by Chouji who swallowed the water from his jutsu.
Almost happened to Deidara when Sasuke pinned him to his explosive clay bird with two large shurikens and sent the bird plummeting down to a minefield he had set earlier, but he manages to escape.
It almost happened in a flashback as well, when Itachi used genjutsu to trick Deidara into wrapping explosive around himself instead of Itachi, but Itachi stopped him because it was his mission to get Deidara to join Akatsuki.
Pain lost one of his remote-controlled bodies when he used it to absorb Naruto's Sage chakra. Without proper training, said chakra turns people into stone frogs.
Kisame suffers this twice. First, his own sword Samehada betrays him for Killerbee/the Eight-Tails because he fed it so much of his chakra while they fought. Then it turns out that the huge water jutsu he used to drain the Eight-Tails chakra and trap Killerbee attracted the attention of Raikage and company. Raikage and Killerbee (rejuvenated by the chakra Samehada just gave him) promptly team up to decapitate Kisame. While this wasJust as Planned, even he said it worked a little too well.
Sasuke absorbed Orochimaru into his body using the technique Orochimaru intended to use to take over Sasuke's body.
Danzo's death is also an interesting case. Having spent his whole life preaching his principles that a shinobi should never show any emotions in battle, and consider the mission to be above comrades, guess how he died? Sasuke pierced his Chidori right through his teammate (whom Danzo had held hostage) to kill Danzo.
In a recent chapter, Kabuto got defeated by Uchiha Itachi, who he himself resurrected from the dead to fight in the war using his Edo Tensei technique. Not just defeated, but forced into undoing the technique, effectively destroying half his side's military power.
Also happened to Obito. He used his Kamui to suck Kakashi into the other dimension, only for Kakashi to deal some serious damage to him when Obito partially morphs into that same dimension to escape one of Naruto's attacks.
In a very satisfying example of reaping what you sow, Jackal, one of the many villains of Fist of the North Star, after turning loose a giant convict called Devil Rebirth against Kenshiro, makes the mistake of thanking him for freeing him from the "monster" he had previously convinced was his long-lost brother after Kenshiro defeats him. Devil Rebirth promptly grabs hold of Jackal in a grip too strong for him to escape, and Kenshiro finishes him off by means of Jackal's own dynamite, the weapon the Dirty Coward of a crimelord used to commit his most despicable acts of the arc.
Fate/stay night: It is already ironic that Kirei Kotomine was killed with the Azoth dagger he gave Rin years before. What is even more interesting is that the dagger was given to him in the prequel by Rin's father, Tokiomi Tohsaka who was Kirei's teacher. It was then used to stab Tokiomi by Kirei while Tohsaka's Servant Archer (Fate/zero 's Archer, aka, Gilgamesh) watched impassively.
Precia Testarossa, desperate to reach Al Hazard before dying of her disease or being arrested by the TSAB, tried to go do the dimensional transference when she had nine out of 21 Jewel Seeds, short of even the 14-seed bare minimum she suspected she would need. She falls to her death as the transference fails and her lair collapses.
Jail Scaglietti took part in Project Fate, an illegal cloning experiment that Precia completed. It's Fate Testarossa, the product of this experiment, who eventually defeated him and brought him to justice.
Even though no one dies, Luffy is beaten around by Foxy for nearly their entire fight. Foxy uses both his power to slow down time and mirrors to reflect his "slow beams." At the end of the fight, however, he's caught by one of his own beams, reflected from a shard of the same mirrors he used earlier, allowing Luffy ample time to set up a truly epic finishing punch.
Also with Eneru, the very gold ball he grafted onto Luffy's arm meant to slow him down becomes the very thing that ends up stopping Eneru's energized death ball and defeating the fake "god".
Moria uses his 'Shadows Asguard' technique in order to absorb one thousand shadows on the island to fight Luffy. While he's much bigger and stronger, he's also slower and struggling to keep the shadows in. Luffy defeats him handily through a combination of Gear 2nd and Gear 3rd.
Recently, Robin has been starting to fall into this whenever she tries to use her Devil Fruit powers to restrain opponents with Devil Fruit powers of their own that are activated by touch. Since the copies of her limbs that her powers create still count as her real limbs, this usually results in Robin falling victim to those powers herself. So far, this has happened with Ain and Sugar.
Subverted in Rave Master with Six Guard's Sean. When he's knocked out by his own sleep-inducing power, he ends up fighting in his sleep and is even stronger than when he's awake. He grinds his teeth, too.
One of the Death Note owners, Kyosuke Higuchi, is killed when his notebook is repossessed by Light, who recovers his memories and writes Higuchi's name in a scrap that he tore out of the notebook earlier.
Light himself suffers this fate at the very end of the anime when Ryuk makes good on his promise to Light in the very first episode and writes Light's name into the Death Note.
Having throught he'd cleverly defeated death, Szayel-Aporro learns that all he did was accidentally absorb a drug Kurotsuchi had placed inside his lieutenant on the off-chance anyone would use her as an incubator. The drug speeds up his perception of time. When Kurotsuchi stabs him, killing him only takes a few seconds but, thanks to the drug, it feels like centuries to Szayel-Aporro.
Charlotte traps Yumichika in a technique that relies on this trope to kill narcissistic characters in an ignomious way by ensuring their death passes unseen and unmourned by anyone. However, all it does is allow Yumichika to unleash his Coverblowing Superpower without fear of his colleagues uncovering his secret, resulting in Charlotte suffering this death by this trope instead of Yumichika.
Hachigen kills Barragan by teleporting his rotting arm into Barragan's stomach, causing him to age himself to death.
When Tousen's hollow form gives him the ability to see, he becomes so focused on his new-found sight to the exclusion of everything else, allowing Hisagi, his former lieutenant, to sneak up on him and land the finishing blow from behind.
In 421, this happens to Aizen. Relying on the Hogyoku for power was fine when it still considered him a worthy master. The moment it didn't, the Hogyoku took back all of the power it had given him leaving him vulnerable to Urahara's sealing kidou.
One could easily argue that Aizen did this willingly, even though it was unknowingly. By setting the proto-arrancar "White" out loose in the human world, he caused Isshin and Masaki to meet. This resulted in Ichigo's and his sisters' conception. Aizen willingly attempted to build Ichigo's strength and feed his potential in order to create an opponent that would allow him to reach higher levels of transcendency. That eventually backfired magnificently, as Ichigo gave him an emphatic Curb-Stomp Battle, before attacking him with Mugetsu, which would weaken Aizen enough for Urahara's sealing kidou to take effect.
In 466, Yukio tries to kill Toshiro with an inescapable Zerg Rush of monsters programmed to zone in on Toshiro's location and crush him. Then Toshiro flashsteps right next to Yukio and freezes his Fullbring. Yukio can't do anything but scream in terror as his own monsters surround him and Toshiro, knowing full well that Toshiro will be able to dodge their attack while he can't.
Robotech: The Shadow Chronicles is basically an epitome of this trope. Basically REF has weapons based on technology provided by Haydonites. When they clash, the question becomes: will Haydonites manage to turn humans' Haydonite-based weapons against humans, or will humans defeat Haydonites with Haydonite-based weapons? Both actually happens, but in the end humans win, at least for the moment.
In the Fanservice-filledQueen's Blade, the assassin Melona's primary means of attack is to squirt some sort of acidic fluid... from her breasts. Reina defeats her by blocking off her nipples with her Breast Plate, causing the acidic liquid to back up, swelling Melona's breasts to massive sizes.... and blowing them up.
Ranma ˝ includes this on a few occasions, usually as a way for Ranma to beat opponents who, for whatever reason, outclass him. The best example is the Musk Dynasty story; Ranma's opponent Herb is far stronger and better trained at ki attacks then Ranma is, and knows how to disrupt the Hiryu Shoten Ha, which normally feeds off of the opponent's ki (which makes it a tentative example of this trope). Realizing that his opponent's attacks have left large quantities of ki floating loosely, he tricks his foe into apparently destabilizing the Hiryu Shoten Ha again- instead, Herb actually gives Ranma what he needs to gather all of the available ki, coalesce it into a single massive bolt, and drop it right on his head.
In an earlier story, the Date Monster of Watermelon Island, Ranma is stuck in female form and defenseless against Tatewaki Kuno, who has lost his delusions and thus is capable of actually concentrating on defeating Ranma for once. Aware that his Training from Hell has conditioned him to attack watermelons, s/he slips one onto Kuno's head, whereupon he knocks himself out cold and restores his memory- and thus his delusions.
The Martial Arts Dining story might also count by a technicality; Ranma's winning move, the Parley du Foie Gras, not only takes advantage of a loophole in the rules, but also turns Piccolet Chardin's normally advantageous mutations into Ranma's key to victory. Piccolet's rubber-like face allows him to eat faster then Ranma can, but also makes it easy for Ranma to force his own food down Piccolet's throat.
Actually referred to by name in an anime-exclusive OAV; early into the Christmas Scramble OAV, Kodachi mockingly points out that Kuno's unidentified but huge present is far too big to even get through the door, never mind into Akane Tendo's stocking. Kuno, horrorstruck, points out that he's been hoisted with his own petard (probably not in the original Japanese, though, as Kuno's Shakespearean references are a Woolseyism). And is promptly squashed under Shampoo's bicycle.
In Mobile Suit Gundam Wing Endless Waltz features a Heroic example of this trope. Heero uses his Twin Buster Cannon to destroy the Big Bad bunker. Though Heero survives Wing Gundam Zero is destroyed by the third shot's recoil.
Ah, but the super weapon with a programming defect may as well be the same as the mad scientist whose creations kill him in the end. This also happened in the live-action movie, G Savior, directly to the main antagonist.
Mobile Suit Gundam Seed Destiny has the Federation once again trying to nuke ZAFT into space dust... only to get spectacularly one-upped when ZAFT's Neutron Stampeder detonates their nukes in-flight and even while still in the launch tubes. And yes, it's every bit as plausible and awesome as it sounds.
Mobile Suit Gundam and its related side stories showed that the majority of Zeon was hoisting their own petards. Many of the soldiers and higher ups are Glory Seeker-types who seek to outdo their own ace pilots, no matter if their actions harm their chances of actual victory.
In the mid-season of Code Geass R2, when he is badly wounded and expecting help from Charles, V.V. instead gets his Code taken from him by Charles out of anger for lying to him too many times, and is left to die.
Jessie Mavia in Kinnikuman lost to Kinnikuman when he was goaded into going on the offensive. This was a mistake because, while Jessie is a master at move counters and reversals, he has no original moves of his own. Taking the initiative as he did left him wide-open to Kinnikuman reversing Jessie's attacks.
In Pokémon Diamond and Pearl, Paul released his Chimchar because it lost one too many battles, and considered it weak. In the Sinnoh League, he was defeated by Ash who used the same Chimchar...as a fully evolved Infernape.
Bianca's Minccino in Black and White had a dreadful habit of cleaning anything it found dirty. Bianca pulled out a Poké Ball that was just as unclean as Ash's badge case (she delivered that to him as well), and when Minccino saw that, it darted up to clean it off. After that, though... wiggle, wiggle, wiggle, click.
Cyrus's grand scheme was to possess Dialga and Palkia to create a new dimension for him. However, when they are released, the dimension fades away and is brought to a more timely end by the not-yet-fully-released Dialga and Palkia - but not before Cyrus enters the portal.
Baccano! provides an indirect example of this. After first inflicting damage on Szilard Quates herself, Ennis, one of his created homunculi, gives Firo Prochainezo instructions with her dying words on how to finish him off. Consequently, since the method of killing Szilard involves absorbing his knowledge, Firo is able to save Ennis.
Most of The Seven Kin of Purgatory were defeated this way.
Rufus Lohr, of Sabertooth, memorizes magic he's seen and imitates it. He's kicking Gray around like a soccer ball until Gray imitates Erza's Heaven's Wheel by creating dozens of ice weapons at once, going too fast for Rufus to memorize.
Angel of the Oración Seis is taken out by Lucy because of this. Lucy holds an incredibly deep love for Stellar Spirits, so when Angel used the Mind Reading spirit Gemini against her they are moved by her passion and refused to fight.
And then you have Master Hades of Grimoire Heart. His Evil Plan involved reawakening Zeref. Too bad Zeref had a Heel Realization and wanted no part of said Evil Plan, and absolutely annihilated Hades for even thinking of trying to use him for his own ends.
Tenchi Muyo! has a spectacular moment in Episode 7. The episode's main plot of Ryoko and Ayeka trying to win Tenchi's heart reaches its peak when they trick Mihoshi into returning to the Galaxy Police and locking Washu in her lab before turning on each other. Everything falls apart spectacularly when Sasami defeats an alarm Ayeka put in to keep Ryoko out, the two girls finds out Washu was already in his room, fall prey to said alarm (which launches them into the lake) and, for good measure, Mihoshi returns... and crash lands on the house.
Gold and Silver from Yaiba are both defeated by their own features: Silver is knocked out when he accidentally shot his electrical laser while in a water pool and Gold is impaled by Yaiba's sword after the latter took advantage of Gold's super strength and super elastic arms to get propelled with enough force and speed towards the titan.
Reiji Mizuchi from Metal Fight Beyblade loves striking fear into his opponents till they're broken wrecks. Ginga ultimately delivers an epic Shut Up, Hannibal! on him. The sight of Ginga not being afraid of him causes him to have a Villainous Breakdown and be overwhelmed by his own fear, allowing Ginga to defeat him. He's last seen as the same broken wreck he typically left his opponents in.
From the original Anime/Beyblade , one of Max's opponents, Queen, is using a modified attack ring with a sharp blade in an attempt to strip down Max's beyblade to obtain his bitbeast Draciel, but Max figures out a counterattack that causes the attack ring to spin in the opposite direction. The special attack ring was made only to work in one direction, so when Max's beyblade reversed it's spin direction, it ended up backfiring on Queen's own beyblade and literally tearing it apart.
In Pokémon Special, Black only managed to beat Lenora because she had her Stoutland spam Take Down, a move that, while powerful, whittled down its HP and allowed it to be taken out in one good hit.
Lupin III has used the Self-defeating villain version a few times.
In Manga.Lupin III, we have a literal example of the phrase, as Lupin hires an assassin to kill a Yakuza boss ( who is a split personality of the assassin ) and the boss has set bombs all over his house.
in Lupin III: Travels of Marco Polo – Another Page, Bernardo, who tries to use his Kill Sat to kill Lupin's gang, instead ends up right in the center of the shot. That's why you don't try to screw over Lupin, especially when a Chinese triad boss with connections to your weapons company owes him a favor.
In the anime version of THE iDOLM@STERPresidentKuroi convinces the audio technician from the Idol Jam to conveniently forget where he put the CD with the 765PRO idols songs. This comes to bites him in the rear, when Chihaya starts to sing in acappella, making the tech (and crowd) be so moved by the scene that he restarts the audio in the next chorus, effectively creating a greater effect on the public than it would be if she had just started singing normally.
Also, this little stunt was the last drop for his own group of Idols who didn't want to keep up with his crap anymore and quit his company before the song Chihaya was singing even ended.
In Ultimate Teacher Ganbachi plants a spike to the ground in order to kill Hinako who was dropping from above, only to be nudged towards the spike and have Hinako drop on top of him, impaling him in the process.
Rikka found out about Yuuta's 'Dark Flame Master' persona (which Yuuta sees as Old Shame) after seeing him put on the act one last time before school. In his defense, he really wanted it out of his system and he thought no one was around to see.
Sanae got herself entangled on her very long hair after trying to use it like... bolas.
In the 12th volume of High School D×D, Cao Cao was so Crazy-Prepared that he also neglected the fact that his Medusa eye (which he had to replace his normal eye thanks to a Boom, Headshot from Issei) is weak to Samael's blood that is supposedly weak against dragons (and apparently, snakes). Of course, no one could have seen Issei coming Back from the Dead when he should have been Deader Than Dead thanks to being coated by it. Not to mention, Issei practically stalled him by explaining something which was really out of character (from Cao Cao's perspective at least) and fires off a bullet which Cao-Cao admits was foolish.
In Shin Mazinger, Tsubaki mentions this trope by name over Viscount Pigman's plan to obtain Zeus' hand. Inflicting her with a curse using her Tragic Past concerning Kenzo Kabuto and her brotherTetsuya Tsurugi, Pigman, disguised as a repentant Baron Ashura, attempts to get Tsubaki to reveal Zeus' hand's location, especially as Kouji and the Mazinger-Z are being beaten by the Super Prototype Energer-Z, seemingly being piloted by the revived Kenzo. However, as Baron Ashura narrates the incident and begs Tsubaki to reveal the hand, she gets the drop on him, realizing that the only way they would have known all of this was because of their time in the pillar. She guts "Ashura" and later forces Pigman to retreat as she does reveal Zeus' hand... for it to turn into Mazinger-Z's ultimate weapon, the God Scrander.
The Deep Blood arc in A Certain Magical Index concludes with what is perhaps the most awesome example of this trope. Touma uses Izzard's power (to turn his belief into reality) against Izzard by making the alchemist think that Touma is an unbeatable Badass. With a dragon for an arm.
In YuYu Hakusho, Yusuke is fighting Rando, a demon that steals spells and techniques. Rando tries to shrink Yusuke with a spell he used on Kuwabara earlier...only for it to shrink him! They're fighting in a swamp, and some algae blocked up Yusuke's ears. The requirements of the spell are that the victim needs to actually hear the incantation, otherwise the spell bounces back on the caster. Genkai states that this is the inevitable result of stealing powers and not earning them- you're bound to miss some crucial info.
In Gundam Build Fighters, Kirara charms Sei into letting her take care of his Build Strike Gundam, which she promptly sabotages. However, she only sabotaged the Mobile Suit and not the Build Booster pack and when the Build Strike falls apart, the Build Booster takes over and swiftly defeats her Gerbera Tetra.