Air Gear: Despite being the heir-apparent to the Flame King Spitfire, Kazu has been summarily manhandled by Aeon Clock, Sora, Nike, Nott-Dagr, and several nameless Gravity Children throughout the series.
In Assassination Classroom, Lovro the hitman dealer was a powerful, talented assassin during his younger days. Despite being currently retired, he's still skilled enough to effortlessly subdue Irina. He's no match for the God of Death, a mysterious figure who abruptly kills Lovro within ten seconds of making his presence known to him. Except not quite.
In Attack on Titan, Reiner Braun serves as a consistent punching bag to demonstrate how strong or dangerous something actually is.
Played for laughs, when Annie's exceptional fighting skills are established through her effortlessly tossing him on his ass.
During the Expedition arc, he is very nearly crushed to death by the Female Titan. This later turns out to be a ruse, allowing him to pass intel on to her without arousing suspicion.
During the battle at Utgard Castle's ruins, the danger of their situation is established when a Titan bites — and breaks — his arm.
Eren's skills as a fighter are demonstrated when he's able to defeat Reiner's Armored Titan in a one-on-one fight. Reiner is forced to resort to calling for Bertolt's assistance to avoid a complete loss.
The power of the Coordinate is demonstrated through sending a Zerg Rush after Reiner and forcing him to retreat.
Eren's new ability to harden portions of his skin is demonstrated through being strong enough to shatter the Armored Titan's armor.
The power of the Thunder Spears is demonstrated by repeatedly and violently blowing Reiner's Titan up, including an attack that blows part of his head off.
During the Battle at Fort Slava, the power of the Middle Eastern Union's naval artillery is demonstrated by blowing the Armored Titan and Reiner to pieces, very nearly killing him. This particular Worfing makes the military realize that We Have Become Complacent and advancements in military technology will be necessary to survive.
When attacking Paradis for the last time, Reiner and Porco are struggling against Eren (who by the way has his Titan brains blown out by Magath, hindering his motor skills).
Bakugan Battle Brawlers: Gundalian Invaders: Aranaut made a strong first showing in the previous season when a digital clone of him threw around one of the main characters like a rag doll. However, the Aranaut in GI has one of the WORST fight records in the show, quickly going from hot stuff to a bit of a joke, usually only winning with help or other circumstances.
Unusually, Tite Kubo sometimes uses villains to establish the new power levels that the story is introducing.
After Luppi's power level was established by fighting Hitsugaya's team, he is one-shotted by Grimmjow as soon as Grimmjow regains his full power to highlight the difference in threat level between the pair to the readers.
Ayon, after effortlessly dominating five different lieutenants, is easily stopped and killed by Yamamoto, reminding readers that of all the characters currently on the battlefield, this is the guy with the strongest chance to take out Aizen.
Szayelaporro and Aaroniero were in a prelude scene to the fourth film to establish the power levels of Hell's denizens.
Ichigo suffered this whenever it needs to be established a new threat is far beyond any threat he has previous faced.
When Byakuya first appeared in the storyline to establish Byakuya's power level.
When Aizen was first revealed as the villain, to estabish Aizen was a greater threat than normal captains were.
Ishida was instantly defeated during Renji's first appearance to establish the difference between Renji's power level and the hollows that had been appearing in the story until then.
Chad has suffered this several times as a set-up for Ichigo's fights.
After defeating several seated officers easily, Chad was easily defeated by Shunsui to establish the difference in power between a captain and a seated officer. This set up Ichigo's fight with Kenpachi.
When Grimmjow's group invades the human world, Chad is almost one-shotted by Grimmjow's weakest Fracción D-Roy to establish the threat Grimmjow's team poses. This is a lead-in to all the fights Hitsugaya's team face and, in particular, leads in to Ichigo's eventual fight with Grimmjow.
Chad is one-shotted by Nnoitra, despite having just gotten 3 power-ups in a row and handily beating Gantenbainne, to establish Nnoitra's threat level prior to Ichigo fighting him, showing how big a gap there is between a Privaron Espada and an Espada.
Rukia, after defeating D-Roy, is one-shotted by Grimmjow to emphasise Shawlong's point about the difference in power between Fracciones and Espada. It sets up Ichigo being defeated by Grimmjow.
Renji had his brand new Bankai ruined by Byakuya in the first appearance of Byakuya's Bankai to establish exactly what Ichigo would be fighting in the supposedly climactic battle of the Soul Society arc (prior to the real villain being unmasked, that is).
Komamura is instantly defeated by Aizen to show Ichigo that Aizen is so powerful, even the other captains can't do anything to defeat him.
When Aizen artificially jumped in power level, Tite Kubo displayed the new power level by having him one-shot three very powerful shinigami at the same time. Urahara, Yoruichi, Isshin.
Kira was one-shotted to establish both the power level and the ruthless fighting styles of the story's newest enemies, the Stern Ritter.
Kenpachi's off-screen defeat at the hands of the final arc's Big Bad, Yhwach, leads to a shock defeat to establish Yhwach's threat level. It was a fake Yhwach who defeats Kenpachi, but it triggers Yamamoto's arrival to fight him; the real Yhwach turns up and kills Yamamoto, throwing the entire Gotei 13 into disarray, demoralising them, and establishing just how different Yhwach is going to be as a villain compared to even Aizen.
Saizo's got a reputation for never having been beaten, but then gets thrashed around by Hanzo in all his battles with the man, and by Sasuke during their second fight.
Jinpachi is introduced stopping a blow from Seikai bare-handed, to everyone's shock. When Seikai was introduced it took almost the whole team to beat him.
Seikai could also barely harm Byakugun for most of their fight. Far more tragically, despite his Charles Atlas Superpower being Nigh-Invulnerability, he is the first Brave to die in the sequel, setting the power level for Susanoo, a Physical God.
Bubblegum Crisis: The AD Police. Despite having high-yield firearms, railguns, powered suits and combat helicopters they often cannot stop rogue Boomers. Their K11s did stop a BU-12B Combat boomer (both getting destroyed in the process, sadly, although the second one was pure jinx on the AD Police side) in "Blow Up", though. Leon sniped Largo before he could pulverize the Knight Sabers in an orbital beam of death, too. As the designated Badass of the team, Priss also suffers from this to some extent.
Cardcaptor Sakura: Kerberos finally returns to his awesomely badass-looking true form... and gets hammered every. Single. Time. Often, it's explained by having Kero's creator be the one to send the threat to test our heroes, but not always. It'd be nice to have Kerberos's true form prove non-useless once in a while.
Somewhat lampshaded in the manga, near the end of the first arc, when they acknowledge Kerberos's vicinity makes The Earthy stronger, and Kero comments to himself "My true form isn't helping at all."
Cardfight!! Vanguard: Dragonic Overlord "The END" has appeared in three fights, used by three fighters. It's always touted as incredibly powerful (as players in real life can attest to), but no one has ever won using it. First, lost to Ren using it, to show the power of Phantom Blaster Overlord. Later, Morikawa used it, to show how good Aichi has gotten. And finally, Miwa used it against Kai to show how strong he is when he gets the power of Link Joker.
Happens twice to Accelerator, once to establish Amata Kihara as a certified Crazy-Prepared badass, and once to show just how inconceivably powerful Aiwass is. In both cases Accelerator, who is otherwise one of the most powerful and dangerous characters in the franchise, barely escapes with his life.
Magic Gods are beings of incomprehensible power, capable of destroying and recreating the entire universe (as first shown by Othinus). Then one is killed, and the rest depowered, by Noukan Kihara. And then all but one of the survivors are banished to another world by Kakeru.
The "Invisible Thing'' oscillates between being on the giving and receiving end of this. When it first appears, it terrifies Fiamma, then in a state more powerful than God. Before it can actually do anything, it's forced back into its seal by Touma. In its second appearance, it's immediately crushed by Othinus, to demonstrate how powerful even an incomplete Magic God is. The third time, it overpowers Kakeru, even though the latter can instantly defeat Magic Gods. And in its fourth appearance, Aiwass easily crushes it again. It should be noted however, that after the third time it came out, questions begin to arise if it's even the same being that constantly keeps appearing. At first Touma considers it a case of Rock–Paper–Scissors, thinking it case of compatibility. However, he soon brushes it off, stating that the third time it came out, it felt it was far more powerful than anything he had encountered before. Describing it as an unbeatable predator who stood at the top of the food chain.
Touma: Is this really the same as... that one from before?
Anti-Skill is the city's elite task force, armed with heavy weapons and armored suits. Their job is to handle anything that Judgment can't, such as armed criminals and high-level espers. If they show up, they will inevitably be curb-stomped to prove the power of the threat.
In Demon Slayer: Kimetsu no Yaiba, Giyu's own creation, the 11th Water Breathing form: Dead Calm is introduced as an ultimate defense-to-counterattack measure capable of completely negating even a strong demon part of the Lower Moons' strongest attack with much ease, as it was shown against Rui. Come the Infinite Castle arc, where Giyu has grown a lot stronger thanks to the Hashira Training and later awakening his Mark, and the best way to show Upper Rank 3 Akaza's ultimate technique: Blue Silver Chaotic Afterglow is extremely strong is to bypass Giyu's Dead Calm.
The Digimon franchise as a whole has Seraphimon. As a Mega-level Digimon, the leader of the Three Great Angels and one of the rulers of the Digital World in the Digimon Frontier continuity, he is incredibly powerful, but you'd only really know this if you're into the Expanded Universe. Whenever Seraphimon shows up in ananime or manga, he is promptly defeated (and outright killed in Frontier), demonstrating just how dangerous the new antagonist is. His debut appearance in the first of the Digimon Adventure 02 movies had him defeated by Cherubimon within thirty seconds of evolving, and that was with another Mega, Magnadramon, assisting him!
Combined with Running Gag, Leomon always dies for this effect. In Digimon Adventure it's to show Etemon is a Not-So-Harmless Villain. In Digimon Tamers, it's to show that Impmon has gone From Nobody to Nightmare. In Digimon Data Squad, where it kind of happens twice, it's to show how monstrous Kurata was when he sent the Digital World on collision course and by inventing a method of permanently killing a Digimon with ease. On the other hand, Frontier's instances were not this trope while in Digimon X-Evolution and Digimon Fusion it's pretty clear they are killing him for the sake of it.
One that has really annoyed the fandom is the first five minutes of Digimon Adventure tri. when the four main Chosen Children of Digimon Adventure 02 — Daisuke/Davis, Miyako/Yolei, Iori/Cody and Ken — are taken out by Alphamon, though it's incredibly hard to tell with just a five minute preview if they were just taken out or out-and-out killed.
And back in the first Adventure, we have Wargreymon and Metalgarurumon, previously shown to be powerful Megas for taking out VenomMyotismon, each being taken down with one hit from Piedmon's trump sword attack. This quickly establishes just who they are dealing with and shows just how much of a level in badass they'd be taking when they finally had a rematch.
The third movie of the Adventure series, Diaboromon Strikes Back, does this to Omnimon. Previously shown to be able to kill thousands of Diaboromon clones in seconds, Diaboromon's new form defeats Omnimon soundly. This is done to hype up Imperialdramon Paladin Mode, who defeats this new Digimon in one hit.
Imperialdramon himself was hit with this hard in the 02 series proper. Despite being a Mega level (and even calling himself the most powerful Digimon of all in the dub) he never once has an actual victory of another Digimon his level ( he only beats two Ultimate levels, and the average mega level is over ten times stronger than the average ultimate, so this isn't particularly impressive). He mainly serves to show how powerful whatever villain he's facing is, but this has the side effect of making him look incredibly weak for his level.
Savers has a peculiar case of a weapon being worfed hard. The GeoGrey Sword proved to be vital to allowing ShineGreymon to win when it was first introduced, but in literally every subsequent appearance it would only end up getting destroyed.
Angewomon and Silphymon are both Ultimate level Digimon and should be similar in terms of strength, yet Angewomon in Digimon Adventure 02: The Beginning is featured in the same Digivolution sequence where everyone else is only going to the lower Champion level, and she is the only Digimon to have trouble fighting Ukkomon's tentacles. Gatomon appears to have digivolved to Angewomon specifically to be defeated and have to revert back and only then DNA Digivolve with Aquilamon into Silphymon.
Durarara!!: Discussed. In his first appearance, Kinnosuke talks about how the police tend to get this kind of treatment in supernatural fiction –- they usually end up laying in their own blood to show how dangerous the enemy is. However, he doesn't really mind this, as it shows that people still believe that cops are strong and powerful.
Eyeshield 21: This applies to some players, most heavily the heavyweight linemen — considering how easily Gaou crushed Banba and the Pyramid Line (previously the standard for strength, tying with the Devil Bats' own center Kurita), Mr. Don (who can smack down Gaou with ease) should be strong enough to split an anvil by coughing at it!
Jellal Fernandes, officially recognized as one of the ten strongest wizards (until they recognize which side he's on, at least) is so powerful that Natsu need to absorb the ultimate magic Etherion in order to beat him. Midnight only needs to land one hit on the poor guy — and he does it off-panel, too. Erza is willing to say Worf Had the Flu, but there are a good many other ways of arguing this one.
This is later reversed, with Jellal single handedly defeating Midnight, along with Angel, Racer and Cobra, ostensibly to remind the audience just how powerful Jellal is supposed to be after having suffered this a few times. What's more he seems to defeat the four with only a middling amount of effort. However, this is once again inflicted on Jellal, along with the rest of Crime Sorcière, by August, the strongest of Alvarez's Spriggan 12.
Natsu is also hit by this relatively often. If he's not fighting the Big Bad, it's likely he'll have a tough time against an opponent. Lucy is also hit with this, to indicate that her opponents are too strong except for Natsu or Erza to defeat.
Makarov, despite being the Big Good and a Wizard Saint like Jellal, has been hit with this a few times to raise the stakes. During the Phantom Lord arc, he's incapacitated by the magic-sapping powers of Aria of Phantom Lord to hype up his threat level; though it's acknowledged by several characters it only worked because Aria sneak-attacked him, as proven when Erza defeats him despite her own injuries and when Makarov returns and flattens his ass with ease along with the Phantom Lord guild master/fellow Wizard Saint Jose Porla. He gets hit with it against during the Tenrou Island arc, where he gets utterly wrecked by Grimoire Heart's guild master and former Fairy Tail guild master/his predecessor Precht "Hades" Gaebolg to show just how much stronger he is (and unlike with Aria, there's no Worf Had the Flu involved and he proves to be every bit as dangerous as advertised).
The fight between Rei and Raoh is this. Rei has been long established as a powerful fighter capable of at least forcing Kenshiro to fight seriously, so it's easy to expect it to be an epic fight... Except Raoh casually beats him up without even using his fists (he punched him with his Battle Aura), prompting Rei to decide to use a suicide attack we see killing Raoh... Except it was actually Raoh visualizing the attack in his mind so he could decide the best counterattack, one that leaves Rei with three days of atrocious pain before the release of death without even scratching Raoh. In short, this fight used Rei to establish not only Raoh's strength but also his genius.
In the second half of the manga, Kenshiro faces off against Falco in the Tentei Arc. Falco is the Golden General, and therefore the successor, of Gento Kōken; a martial art which can undo the effects of Hokuto Shinken's pressure point strikes at a cellular level, making the user immune to Hokuto Shinken's pressure point effects entirely. In other words, he's one of the most powerful enemies Kenshiro had ever faced. He is tasked with protecting the Celestial Emperor, Lui, who was the target of a kidnapping. However, Lin is kidnapped instead, as they look identical since they're twin sisters. Falco agrees to travel to the Land of Asura to set things right, and being the most powerful practitioner of Gento Kōken, you'd expect him to fare well. Instead, he's immediately killed by a nameless 15 year old.
Takumi Aldini. His first appearance showcases himself as Soma's equal in resourcefulness and experience. His loss against Subaru Mimasaka foreshadows the amount of planning Soma would need to overcome him.
Terunori Kuga, eighth seat of the Elite Ten. Backstory-wise, we see how big of a threat Eishi Tsukasa (First Seat) is by the fact that he defeats Kuga 5-0 in a Shokugeki.
Joichiro and Eishi are trounced by the Noir chef Asahi Saiba.
From the New World: Shisei is extremely powerful, not to mention intelligent and coldly rational, compared to the other humans with telekinesis; that is, everyone. He gets a variant of this trope the first time he appears; Shun's creature-in-an-egg project terrifies him, which is the viewers' main indicator of how horrifying it is, since we never see much of it. Played straighter in episode 21: he is easily defeated by (and brutally killed by) a rampaging Akki. Shisei's inability to fare much better against this enemy than anyone else did makes the battle seem truly hopeless.
Fullmetal Alchemist: Used against Major Armstrong by his sister Major General Armstrong. Not only does she get him in tears by standing on his foot, she knocks him through a wall during the battle for the Armstrong Estate.
Scar's defeat of Basque Grand is done for similar reasons, in order to demonstrate how badass Scar is. This is justified in the Brotherhood anime, where we see that Grand's defeat has more to do with his not having all the information on Scar's abilities than anything else. In the 2003 anime, he kills Grand onscreen, and backs it up the next episode by being the first person to do substantial damage to Al's metal frame.
Mustang gets hit with this trope too, although it's less that he gets taken out and more that he fails to take out his opponent, which under most circumstances would mostdefinitelyhappen. When he faces Gluttony with the latter's stomach open, displaying the eye of Truth, his flame attack fails spectacularly as the fire is merely absorbed, prompting Ed to call him useless. Mustang then suggests that he do something about it.
GoLion: Every encounter the titular robot has with a robeast who is a physical threat to Golion is an example of this.
GTO: The Early Years: Machida is the first person to actually beat Eikichi in a duel, since he uses brass knuckles. Ryuji goes to challenge him, but he loses too.
HeartCatch Pretty Cure!: The Dark Precure shows this off and gets one. In the very beginning, she's shown wiping the floor with Cure Moonlight, leading to her depowerment. Everytime she shows up to fight the other Cures, it's just the same, with Cure Sunshine's arrival only barely changing the balance. It isn't until Cure Moonlight is repowered that the Dark Precure is finally given this, which leads to a very painful Villainous Breakdown for her.
Kabeyama, Touko, and Tachimukai, whose special skills are almost useless in the long run against most of the opponents' abilities. Also, want to show how bad the bad guy team is? Have them beat a random team or even the heroes to 10-0 or worse within the first half. This however, can be avert easily after The Hero begins his speak of friendship and how fun soccer can be.
GO introduces us to Kurama and Sangoku, both of whose hissatsus (Sidewinder and Burning Catch, respectively) unfortunately fall victim to being used in order to show how strong the opposing team is, despite the fact that in Sidewinder's case, it's actually a pretty good hissatsu. At least Sangoku gets Fence Of Gaia later on, which proves to be decent at saving a few goals here and there.
Just being the title character doesn't earn Inuyasha an exemption from Worf duties. Generally any fight against a major opponent has to open with the same ritual: Inuyasha unsheathes his BFS; headlong running charge into opponent; sword gets blocked (either directly or by some magic force field), and sparks fly for several seconds; then Inuyasha gets thrown back to the practical horizon. (In this case, the big tough character often does prove capable of beating the opponent handily but still has to give them the chance to toss him. Perhaps it's etiquette?)
Despite appearing only in a single episode and having no build up to his appearance in the story, Goshinki serves as a perfect measuring stick for Inuyasha's full demon form. Goshinki's mind reading power and intelligence, enormous strength and biting power as well as his incredible speed make him impossible for the heroes to handle. However, breaking Tessaiga with his teeth and heavily injuring Inuyasha with his claws awaken Inuyasha's demon blood inside of him, who now in his full demon form has not only superior strength and speed than Goshinki's, but his mindset becomes to bloodthirsty and dangerous that Goshinki's mind reading becomes useless against Inuyasha who doesn't think straight. The full demon Inuyasha effortlessly kills Goshinki, and because of how bloodthirsty he is, Inuyasha can become a much bigger threat to his friends if he doesn't keep his demon blood under control. Additionally, the biting power of Goshinki's teeth later serve as tool in form of Sesshomaru's new sword, Tokijin, meaning that Sesshomaru is now in possession of a sword that rivals Inuyasha's Tessaiga.
Jewelpet Sunshine: Garnet and Sapphie, two of the major Jewelpet characters and more powerful magic casters, are soundly defeated by the Dark Queen in the last arc, showing just how dangerous the situation is, and also showing that they're not part of the legendary Wise Ones.
Jewelpet Twinkle☆: The tournament arc introduces a minor character called Hilde, stated to be the favorite to win the Jewel Star Grand Prix. She promptly loses against the unknown Laiya (Alma in disguise), setting her up as a dangerous opponent for the heroes.
Kakyoin from Stardust Crusaders does this a lot. He claims "no one can just deflect the Emerald Splash", yet this move is deflected or dodged by Star Platinum, Tower of Gray, The Sun, and DIO, who deflects it with a single finger! And DIO kills him by using his Time Stands Still powers in one of both the most memetic and tragic scenes in the series.
Jotaro gets this quite a bit in Diamond is Unbreakable. He gets his flesh melted by Bug Eaten, which would have left him permanently crippled if not for Josuke's healing abilities. It took an all-out barrage of attacks from Star Platinum to deal an insignificant amount of damage to Sheer Heart Attack and then Jotaro gets severely, if not fatally wounded by it (once again, Josuke saves the daynote There's a reason that his Stand has the limitation that Josuke can't use it on himself). And then he gets it again in the Bites the Dust arc where he gets temporarily killed off by Kira using absolutely zero effort along with Josuke, Koichi, Okuyasu, and Rohan.
Despite being acknowledged by Sukuna as the strongest of the unregistered special-grade curses, Jougo loses every fight he partakes in. His attacks are easily intercepted by Gojo, and Sukuna doesn't even need to use any of his own techniques to kill him.
How does Sukuna show he is a really, really serious threat after he gets Ten Shadows, Mahoraga and his true power? By beating Gojo, who was all but invincible until then.
Kaiju No. 8: Chapter 4 introduces a Child Prodigy recruit to the Kaiju Force, Kikoru Shinomiya. Two chapters later, another humanoid Kaiju is introduced who takes her down in one shot. Downplayed in that she's able to keep fighting and hold off a revitalized Kaiju long enough for everyone to get to safety (and for Kafka to arrive).
Kengan Ashura: Variation, in which the character Hassad is introduced as one of the main character's potential rivals but ends up curb stomped a few chapters afterwards to establish the power of Katahara Metsudo's bodyguards. Japanese fans of the manga now use "to Hassad" as a verb to describe the phenomenon where a seemingly-strong character is introduced only to be beaten anticlimactically by an even stronger character.
Kill la Kill: When Nui Harime shows up to Honnoji Academy in the middle of Ryuko and Sanageyama's fight, Satsuki — the most fearless and formidable character shown in the series so far — immediately yells to Sanageyama to get away from her. Sanageyama doesn't listen, however, and charges Nui — only for her to instantly destroy his 3-Star Goku Uniform by removing a single thread, leaving him helpless.
Need a quick way to show off a mage's power? Have them shatter Nanoha's Deflector Shields, which are amongst the strongest in the series and the reason why Nanoha can invoke The Worf Barrage often.
Meanwhile, after her first battle, poor Vita has often found herself on the receiving end of this. May it be a powered-up Nanoha forcing her to the defensive, or Nanoha giving her an Oh, Crap! moment with one attack alone, or Zest smacking her out of her Unison form, it's like she's receiving karmic backlash from her initial beatdown of the main character.
Some chapters later Vita got (rather quickly) trounced again by one of the new villains just to maintain the tradition.
Even Signum got hit with this in Force to show off how powerful the Hückebein are.
As the series as a whole evolved, the Zentradi and Meltrandi in general have become this. Because the conquering giants are so prolific and genocidal, they've already encountered and fought countless spacefaring species in the galaxy. Several of the post-Super Dimension Fortress Macross series have a human fleet encountering remnants of a massive Zentran or Meltran fleet that's been devastated by an unknown alien race (i.e. the new upcoming antagonist). Seeing these ruins make the heroes (and viewers) understand they're about to encounter something more powerful than the Zentran-Meltran, one fleet of which would have defeated humanity in the original series if not for a last minute Heel–Face Turn.
Poor Klan Klein of Macross Frontier is the Proud Warrior Race Girl of the series... and she follows quite closely in Worf's footsteps, getting kicked around fairly consistently despite also having several moments of startling competency.
Magic Knight Rayearth: Whenever one of the trio is set up to fight an adversary on her own, the other two get one-shotted to show how powerful it is and how important it is that she defeat him/her/it.
In the Mashin Hero Wataru Series, Shibaraku and Senjinmaru are overwhelmed almost all the time to show off the power of the opponents.
The Mazinger series:
Mazinger Z: In the original manga, the 18m-tall Humongous Mecha Aphrodite-A, clad in super-tough Alloy-Z, was sortied to stop a mysteryous Humongous Mecha from rampaging through the city. That mecha was Mazinger-Z, "controlled" by a Kouji Kabuto who was learning the hard way that Falling into the Cockpit is not a good idea. When Aphrodite's fist failed to even dent the armor of the unknown robot, and with her being easily tossed aside with a simple motion, Prof. Yumi knew that enemy was extremely strong and dangerous.
And in one episode a secondary character called Saijyo showed he was a badass by beating Boss (who in spite of being the Butt-Monkey when in his robot was a very competent and Acrofatic fighter).
This was also how they showed that the Mykene Warrior Beasts were way more powerful and more dangerous than Dr. Hell's Mechanical Beasts. They almost destroyed Mazinger-Z.
Great Mazinger: Tetsuya was established in both his series and in the situation with Mazinger-Z described above as an AceHumongous Mecha pilot, Combat Pragmatist and highly competent, Hot-Blooded badass. In the reimaginings (Mazinkaiser and Shin Mazinger) how did you show the situation at hand was dangerous and the villain a serious threat? Simple. Pit Tetsuya against said villain and injure him or make him struggle. Even Super Robot Wars uses this to varying extents.
Venus A was also used like a punching bag by the Mykene Warrior Beasts when it needed showing how terrible they were.
UFO Robo Grendizer: Kouji Kabuto had been The Hero for two Humongous Mecha series, facing dozens of enemies and (often) emerging victorious. In the first episode he got shot down easily by Vegan mini-ufos, forcing Duke to reveal his true identity to rescue him. Kouji got subjected to The Worf Effect throughout the whole series.
Mazinkaiser: Both Mazinger-Z and Great Mazinger suffered this within the first two episodes, with both machines falling to Dr. Hell's Mechanical Beast army.
When Shishime Iihiko shows up, Superpower Lottery winner Anshin'in says she can hold him off for 15 seconds while the others run. And that's about how long she lasts, too. Not that running helps.
Supporting Protagonist Zenkichi Hitoyoshi can handle thugs and crazed kendo experts with ease, but he's occasionally used to show the threat of the next Arc Villain. Oudo easily subdues him with his Compelling Voice, Kumagawa toys with him during their fight, and he's even killed by the Gehyoukai. And the aforementioned Ihiko? Crushes him without a second thought.
Lan and MegaMan are defeated by Chaud and ProtoMan in a relatively short battle to establish ProtoMan's power level.
Later on, ProtoMan himself got worfed to showcase the power levels of ShadowMan and Bass. He was also shown on the losing side of a battle against the Dark Navis right after obtaining his new Muramasa Mode and needs MegaMan's help to turn the tide around.
Finally, all of MegaMan's allies got deleted in one attack in the battle against Nebula Grey.
Ace Pilot and Newtype Char Aznable in Mobile Suit Zeta Gundam. Despite having more experience and low level Newtype gifts, as well as piloting a Super Prototype, he underperforms compared to Kamille, Amuro (who's rusty in comparison, yet still proves he's an Ace Pilot), Emma (after suffering from her own Worf Effect before getting the Gundam MK II as her primary machine, which takes her to a level of badass), Reccoa Londe, Haman Kahn and Paptimus Scirocco. The latter two in particular absolutely destroy Char by tag-teaming him in the final episode, with his Hyaku Shiki being more or less batted around like a rag doll between them.
The Mysterious Cities of Gold: In comparison to the original series (where he was all but unstoppable), Mendoza very rarely proves a match for the arc villain in the sequel (He always puts up a good fight though).
Sasuke Uchiha suffers from this a lot, especially pre time skip. Kakashi, Rock Lee, Itachi, and The Sound Four all beat Sasuke fairly quickly and easily, with the latter two actually helping lead to his Face–Heel Turn. He still suffers from it post time skip, even getting hit with it 3 times in a row at the Kage Summit, and the fight with Killer B...
Speaking of B, he got the worf effect to later ninja who later go on to be opponents Sasuke keeps up and beats.
Sasuke may count as a deconstruction pre-timeskip, since being repeatedly defeated led to him believing he was falling behind which eventually drove him to seek out Orochimaru for power. It didn't help, however, that no one stopped to explain to Sasuke about Naruto's unbelievable learning curve because Naruto originally couldn't control his chakra at all, and it was only his vast reserves that pulled off his main cloning jutsu. Said cloning jutsu sends all the experience of the clones back to the original.
Even characters who gave Sasuke trouble earlier in the series wound up getting the Worf treatment in some way or another. Rock Lee especially, since after curb stomping Sasuke, he proceeded to get quickly defeated by minor villain Dosu, and then get an arm and leg absolutely destroyed by Gaara after suicidally opening his inner gates for a severe boost in strength.
This also happens quite frequently to Kakashi Hatake, more so post-time skip. In Part 1, Itachi Uchiha proceeds to curb stomp him, with ease. In Part 2, Kakuzu had every advantage, leaving him nearly helpless offensively (Kakashi, however, mentions that he could have won with the Mangekyo Sharingan, but would have ended up in the hospital again). We also see him nearly killed by Deva Path Pain, who takes little to no effort to defeat him and set him up to die.
The ANBU black ops, despite being referred to as incredibly powerful, never seem to actually do anything other than lose.
This happens a lot in Naruto. Aside from the examples listed above, Orochimaru got curb-stomped twice by Itachi, once before the series, and again at the end of Sasuke's fight with Itachi. Deidara made his introduction by defeating Gaara, and then lost to Sasuke, who in turn got hammered by Killer B and the Five Kages (including Gaara). Probably the best example is when Pain worfed the entire Leaf Village!
Before Pain worfed the entire Leaf Village, he got the good of a double-layer worfing. He was said to have worfed Hanzo the Salamander, whose only real feat at the time was the worfing of Orochimaru, Tsunade, and Jiraiya in their prime.
One interesting case is Naruto's victory over the Third Raikage. In this case, his victory was used not to show how powerful he had become, as his best attacks still failed to work, but how much he had progressed tactically.
Curiously, it happens to Madara Uchiha after becoming the host to the Ten Tailed Beast. While at first shown to be an Invincible Villain, Guy managed to almost kill him using the Eighth Gate, was clearly losing against Naruto and Sasuke's latest Next Tier Power-Up before he absorbs the God Tree and then he is literally backstabbed by Black Zetsu who is actually the will of the real Final Boss of the series.
Any dragon that shows up will inevitably be defeated by someone in an awesome manner. Albireo has a dragon acting as his guard dog, Kaede took out a dragon while blindfolded, Yue defeated a griffin dragon to prove she Took a Level in Badass, and Jack Rakan is said to have [fought the Sacred Guardian Beast of the Empire, the Ancient Dragon Vrixis Nagasha on even footing. It's one of the most powerful beings in existence, and it still worfed. It shows up again in chapter 281, and gets its ass kicked. Stupid reality warpingBig Bad.
Dynamis also has some trouble with this: after his debut, Nodoka steals his Reality Warper staff and uses it teleport away, Chachamaru obliterates his massive shadow summon, and later on he gets his ass kicked by Negi's Demon Form.
Fate's Quirky Miniboss Squad had precisely half a successful battle before this set in.
And now the whole of Ala Alba is suffering from this at the hands of the new Averrunci.
The go to Worf's in Ala Alba are Kotarou, Kaede, and Setsuna. Kotarou and Kaede were both made the Worf to Albireo in the Tournament. The event in the Chao arc that established her as a contender and Big Bad was that she outmaneuvered Kaede and Setsuna at once. Chachamaru also held this hat during the Magic World arc.
Anytime they need to lays downs that "Negi's students are really strong", some character will get worfed in some way, even Negi himself.
Happens to Asuka Langley Sohryu quite often in Neon Genesis Evangelion. Throughout the series, her achievements as a human and a pilot are often noted; however, she is never once shown defeating an opponent by herself. By the end of the series, she is Mind Raped by an Angel, and subsequently becomes so bad at piloting she suffers a nervous breakdown. In End of Evangelion, she finally manages to get her act together against the Mass Production EVAsonly to get speared through the eye shortly before suffering one of the most Cruel and Unusual Deaths in the entire damned series.
Subverted in Rebuild of Evangelion, where Asuka makes her entrance by one shotting the new attacking Angel, just to throw this out the window and show us why she's considered an Ace Pilot to begin with. She does require help defeating the 8th Angel (Sahaquiel in this one), but teamwork between the three pilots was kind of the point of that fight, even in the original. And she can't be held accountable for being absent during the next two Angel battles.
Played straight with Mari during the battle against the 10th Angel (Zeruel), where she's soundly defeated in a similar fashion to Asuka in the original series, despite putting up more of a fight and even successfully activating EVA-02's Beast Mode, which only serves to reinforce how powerful the Angel is.
In the manga, Asuka also debuts by defeating an Angel by herself in what is stated to be a record time.
The Big Bad of the arc often does this to several of Luffy's crewmates before Luffy goes to fight him (Buggy did it to Zoro, Arlong did it to Zoro and Sanji, Eneru did it to Sanji, Robin, Zoro and Wiper, and Moria and Oars did it to the entire crew), typically to establish that he's too strong for anyone except Luffy to defeat (or to remove the stronger crew members -i.e. Zoro and Sanji- from the equation). The villains often do it to minor characters to reveal just how strong they are, sometimes offscreen (for example, Mr. 3 supposedly captured a criminal worth 42 million, and this is revealed back when Luffy's bounty was 30 million). Although, 42 million is in fact a fairly low bounty for the Grand Line; Luffy's bounty shot up to 100 million as soon as he had the chance to prove himself against Crocodile, an opponent stronger than what the East Blue generally offers.
Speaking of Crocodile, he is the first villain to completely defeat Luffy (Smoker is a Hero Antagonist fit for the Grand Line instead of the East Blue), showing how the threats in the Grand Line are way above those of East Blue.
The Straw Hat crew as a whole can be used for a variation of this. During the Whitebeard War following Impel Down, antagonists who had defeated the Straw Hats without question in their first encounters (Aokiji, Kizaru, and Mihawk) have their initial moves blocked almost effortlessly by Whitebeard and his commanders Marco and Jozu, which quite clearly displays the weight class we're seeing for these characters. Further, Little Oars Jr. was defeated easily by the combined power of three of the Seven Warlords of the Sea, when his zombified ancestor took all nine Straw Hats and then some (although Oars was bigger and presumably much stronger than his descendant and Oars Jr. didn't have the Rubber Man powers or inability to feel pain that Oars possessed as a zombie).
Luffy's older brother Ace is also hit with this. Though he is quite strong compared to Luffy in both devil fruit and combat abilities, he's also used to show how much stronger certain characters are. In his backstory, Whitebeard easily defeated him more than a hundred times, Jimbei tied with him in a match that nearly killed both of them. Blackbeard also takes him down after a relatively short fight, and Akainu burns and eventually kills him.
Luffy's rival Smoker shares the same fate as Ace. While defeating Luffy and proving that he is a Worthy Opponent, he immediately gets worfed by Dragon the Revolutionary. And usually when Luffy is about to be captured by him, a character with few or no feats shows up to save him from Smoker and by this proves his strength. In Loguetown it was Dragon, in Alabasta he tied with Ace, and in Marineford Hancock easily broke his weapon. This is taken to extreme levels during Punk Hazard, where he is beaten by no less than 4 characters: Trafalgar Law, Caesar Clown, Vergo and then Doflamingo (though in Caesar's case, he was handicapped by not being inside his own body), the latter of whom would've killed him had it not been for the intervention of Aokiji.
Smoker's subordinate Tashigi is also pretty bad about this. During Punk Hazard, she is cut in half by Law, then knocked down by Vergo, and against Monet, despite dealing the final blow, she had to be saved by Zoro beforehand. Beforehand, she was trounced by Nico Robin in Alabasta to show how strong Robin really is.
On the other side of the equation, certain villains are used to establish how strong the Straw Hats have gotten after a training arc or so. The epitome of this would have to be the New Fishman Pirates; their primary purpose may have been to personify the racial tensions between fishmen and humans, but that got overshadowed by their secondary purpose, which was to serve as fodder for the Straw Hats, so they could show off how ridiculously strong they had gotten over the course of the Time Skip. Case in point: Zoro (one of the aforementioned examples of this trope mentioned above) one-shots their captain, resident Big Bad (Wannabe) Hody Jones, underwater (where fishmen have their strength multiplied several times), proving that any one of the Monster Trio could have taken Hody down easily during the Final Battle of the arc. Hody had just taken down another pirate crew while completely restrained by chains to establish how dangerous he was, and his defeat at Zoro's hands was a prelude to how the rest of the battles during the arc would go. The rest of Hody's crew (including one hundred thousand foot soldiers, comprising of fishmen and human slaves alike) fare even worse, as Luffy knocks out half of them with his haki as the opening volley and lets the other Straw Hats have their pick of the rest.
Pacifistas end up being hit by this trope pretty hard. Before the Time Skip, the Straw Hats had to use basically every resource they had in order to take down a single Pacifista. After the skip, Luffy smashes a Pacifista with one punch, and Zoro and Sanji destroy another in a single move - and their dialogue afterwards implies that each attack would have been a One-Hit Kill on its own.
Giants have had a problem with this trope. While the average human would have a problem dealing with them, they often serve as fodder for the stronger characters to show that size isn't that big a deal. The most imposing giant so far was Oars, who had the benefit of being a zombie immune to pain. His descendant Oars Jr. plows through some Mooks only to become a punching bag for the Warlords. Luffy's strength by Dressrosa is displayed with him one-shotting a giant. Big Mom had wanted to gain control of Elbaf's army, reputedly the strongest in the world, yet she utterly devastated them as a five-year-old.
Jack "the Drought", oddly enough, gets worfed in his favor: Soon after being established as a dangerous, unstoppable pirate, he proceeded to get trashed twice in a row, and rather catastrophically at that, even if he survived both times. Why in his favor? First time was his overconfidence leading him into a fight with multiple Vice-Admirals (including Garp), one Admiral, and the ex-Fleet Admiral all at once, and somehow surviving to have the bad memory, even if he was reported as dead. The second time? He tried to shoot Zunisha (an elephant big enough to carry a huge country on its back) with an entire fleet's worth of cannons, thinking that'd be enough, only for it to one-shot them all in return. Sure, he lost his fleet, but he did somehow survive being slapped with a trunk that could be an island in itself from sheer size. Instead of learning how tough the others are, we learn how stupidly overconfident, if still extremely powerful, Jack truly is.
Luffy himself finally ends up on the receiving end of this trope in the Wano Arc, when he decides to face off against Kaido (one of the Four Emperors of the Sea and proclaimed to be the strongest creature in existence). At first, it looks like it's going surprisingly well, as Kaido is caught off-guard and Luffy absolutely pummels him in Gear Fourth. Then, Kaido gets up without a scratch, sighs, and knocks Gear Fourth Luffy out cold in a single hit of his club. The form that utterly stomped Doflamingo is treated only as a mild annoyance at best to him.
The aforementioned Jack is shown to cower before his fellow crew member Queen despite his unwavering arrogance shown before, showing how strong Queen must be. Queen, however, is then taken down by Big Mom in 2 hits!
The first chapters of the Kozuki Oden flashback fully show how powerful Oden (the only person to ever leave a scar on and, were it not for Orochi's underlings timely intervention, probably kill Kaido) was, able to effortlessly defeat a mountain-sized boar and clash roughly on par with Whitebeard himself. And then he runs off eagerly, all enthusiastic for a fight, and (admittedly, taken by surprise and not too wounded afterward) get sent flying in one hit by Gol D. Roger.
During the Thriller Bark Arc, the Straw Hats have to fight a zombified "Ancient Giant" and only barely defeat it after a prolonged battle that lasted hours, and only because Luffy gained a one-time Super Mode that increased his strength a hundred-fold. In the Wano Arc, Kaido has ten similarly sized giants on his crew, but they're treated as fodder this time around, several being taken out in a single hit. It also indirectly shows that Moria would've almost certainly been crushed by Kaido a second time had he attacked, even with his zombie army.
After the Onigashima Raid almost all the Beast Pirates are effortlessly defeated by Admiral Ryokugyu, including King and the aforementioned Queen, and then fights all the defenses of Wano alone. And then right after that happens, Ryokugyu himself is forced to retreat when he discovers that Shanks is nearby. Indeed, although they defeated Big Mom together, Law and Kid both suffer disastrous defeats at their next destinations from Blackbeard and Shanks (respectively), showing that although they are incredibly tough, the strength of an Emperor by comparison is no joke.
When "Science Captain" Sentomaru was introduced, his boast of "strongest defense in the world" was quickly and properly demonstrated as something to be taken seriously, and played a big part in dealing the Straw Hats their single most crushing defeat at the time. When he's re-introduced in the Egghead arc, though, Rob Lucci shreds right through that same "strongest" defense in a single savage blow, demonstrating that the former CP9 member and current CP0 leader is still someone not to be underestimated.
In Egghead, we see the true power of Gear 5. Kizaru, who had once defeated the entire Worst Generation himself, and is an Admiral, now is perfectly beatable by Luffy in a duel.
During his introductory fight against Mosquito Girl, he manages to tear her legs off and incinerate an entire city block before Mosquito Girl powers up and tears him to shreds. Only Saitama's intervention saves his life, and it's this that prompts him to become Saitama's disciple.
Armored Kabuto smashes Genos into a wall and knocks him out with one blow, and this is before he powers up.
The Sea King spends an entire episode trashing about eight different heroes, including four A-Classes and an S-Class, as well as Sonic. Then Genos shows up, and... well, you can guess. Justified because a) he mistakes the Sea King for just another mook, thinks he's defeated him in one blow, and lets his guard down, and b) he jumps into the path of an acid projectile to save a young girl from being melted.
This is then deconstructed after the battle, when a heckler points out that if Saitama could defeat the Sea King with just a single punch, then the heroes who fell to the Sea King must have been pretty weak and should be considered failures who sacrificed themselves for nothing. In order to protect the fallen heroes' reputations, Saitama lies that they'd weakened the Sea King enough for him to show up, deliver the final blow, and then take all the credit.
Ash is hit by this for Gym Leaders in almost every time they get to have more than one episode to show how dangerous they can be towards him, before he beats them back for their badges. The only subversion is Wattson, who got steamrolled by Ash's Pikachu when the yellow creature was overcharged with electricity.
Ash's Charizard is regarded as one of, if not the, strongest mon amongst all the main characters' teams. So powerful, in fact, that he can stand toe to toe against Legendary Pokémon, andwin. However, he has also been a victim of this trope at least two times.
Dragonite in the Orange League Tournament (granted, Charizard was already weakened earlier by an Electabuzz and was still able to overall hold its own against Dragonite better than the others).
Dusclops in the last Battle Frontier battle against Brandon. (Although for that one, Charizard was winning until Ash ordered use Seismic Toss (a Fighting type move) to end it... but completely forgot that Dusclops is a Ghost-type.)
There's also the episode "Charizard's Burning Ambitions", where it gets slammed twice with a stronger Charizard's tail, then slammed face-first into the ground, then kneed in the stomach... it just goes on and on until the Charizard's caretaker makes it give up. This is arguably the whole point of the episode, as it showed Ash's Charizard it wasn't particularly strong for a Charizard. This episode caused it to undergo constant Training from Hell, turning it into the badass it is today.
Paul is used for this twice too. Wanna prove that Cynthia is untouchably strong? Watch her One Hit KO Paul's Pokémon one by one. Has Brandon been getting stronger? How about a 6-0 victory using only three Pokémon?
Ash's Torterra has fallen victim to this by losing every battle it's been in since it evolved to show just how powerful the other Pokémon is. This is mostly due to being moved aside in favor of Infernape. Bizarrely enough, the exception seems to be any battle against Team Rocket, where it's shown to have no problems.
Ash's (originally Dawn's) Buizel is another offender from that season. In its debut, it easily defeats Ash's Pikachu, Dawn's Piplup and Zoey's Glameow one after another but after that it usually loses to whatever opponent it's facing and is often the first pokemon to be beaten when it appears in a gym or rival battle to show how formidable and prepared Ash's opponent is.
Not as bad as the other examples, but Ash's Bulbasaur seemed to get defeated a lot in Season 1 only for another Pokemon such as Charmander or Pikachu to defeat the opponent.
Misty's Starmie is a pretty regular victim of this. Despite being the evolved form of Staryu, Misty's Staryu has been shown winning way more battles than her Starmie. It's shown to be pretty useful when travelling through water or saving people's lives but once a battle starts...
Brock's Vulpix is a similar offender. Its introductory episode has it unleash a very impressive Fire Spin to curb stomp Team Rocket. It does it again a few episodes later, with an even shorter fight. Then it's made an example of by Jessie's new Lickitung, locked in a hopeless fight with its identical clone, used as an ineffectual delaying tactic against an illusory Teddiursa in Pokémon 3, demonstrates Skarmory's superiority over its type disadvantage, before finally getting in one last Curb-Stomp Battle against Team Rocket and subsequently Put on a Bus.
Speaking of the aforementioned Lickitung, in its debut episode it curbstombs all of Team Rocket, gets captured with difficulty, then goes on to just as easily beat all of Misty's team simply by licking the Pokemon. It only loses because its lick doesn't work on Psyduck and only caused it to use it hidden powers. Every appearance afterward it gets taken out just as quickly and easily as the rest of Team Rocket's Pokemon.
Iris's new Dragonite managed to join the Worf train. After proving even a 4x type advantage isn't enough to take it down, it loses to Ash's newly evolved Krookodile, the first to get knocked down when the Kami Trio came back, beaten by Drayden's Druddigon in the middle of its best attack and got laid out by Charizard when he returned to Ash's team. Its reappearance in Journeys didn't do it many favours, getting a decent showing against Ash's Dragonite before being comically taken out by Dracovish in the latters first battle.
Even Ash's Pikachu gets this from time to time, though usually an odd variation of it. Despite its ability to effortless defeat Team Rocket single-handedly time and time again, they will often successfully capture or even one-shot it if the plot demands that another character/Pokémon of the day prove themself. If the episode involves a featured Pokémon struggling to learn to fight better, or a trainer trying to prove that they are strong enough, expect Pikachu to get taken out of the picture very quickly. Though it's usually still up and ready to deliver the finishing blow that sends Team Rocket blasting off again.
A human example is Sanpei and his Greninja. Their debut episode had them both at their best (despite Greninja being a Frogadier) and giving pointers to Ash and Froakie. Every episode after that once Sanpei got Greninja, however, the two can't live fighting their enemies which Ash and his Froakie/Frogadier/Greninja/Ash-Greninja beat effortlessly the next second. It gets even sillier when they're the only two people who lost in a ninja war and neither side ended up losing big time.
Korrina was, ironically, at the top of the world when she didn't properly train her Lucario (similar to Iris's Dragonite). After mastering Mega Evolution, the two have faced defeat after defeat. Her Lucario was taken down by Ash's Pikachu in the rematch, and then she was owned by Alain's Mega Charizard X to establish he was steamrolling through the gyms at record time to enter the Kalos League. Then, Korrina comes back during Pokémon Journeys as a PWC participant ranked higher than Ash, but her Mega Lucario (and Mienshao) get both taken down by Ash's fresh Dragonite without much issue. Then it turns out Korrina and her Mega Lucario were owned even worse by Galar Gym Leader Bea, who didn't even use Gigantamax while fighting them at Korrina's gym, calling her weak which, by now, wouldn't be wrong to say.
Ash's Lucario gets this during the "2021 Special Winter Arc", which is set after its victory against Bea after using Mega Evolution once. It gets easily apprehended by the Team Rocket trio of the other dimension to show how threatening they were and remains a Distressed Dude with Goh's Inteleon until the very end when it's rescued thanks to a Deus ex Machina by Arceus answering prayers all of a sudden without having done any battling. Cue the group shot ending.
It once more gets hit by this during Greninja's return episode, where it gets bodied hard against the frog, who's not even in his Ash-Greninja form, likely as an excuse to have Greninja be superior enough to mentor it in its own aura senses.
The above leads to a very strong worf effect on Raihan, whose Gigantamaxed Duraludon goes down by a big Aura Sphere from Lucario, who wasn't even using Mega Evolution and wasn't damaged at all.
Alain gets hit with this trope in the first round of the Masters Tournament, only managing to take out Leon's Rillaboom (who had already defeated his Chesnaught), before Leon's regular Charizard makes quick work of his Malamar and Mega Charizard X.
Unless it's against a wild Pokemon or someone generic, Red's Poli tends to get knocked out the moment it pops out of its Pokeball, even and especially after it evolved into Poliwrath. Especially kind of sad seeing how it's his first Pokemon (which he had for years before getting any other) and logically should be the strongest. No wonder Red uses Saur and Pika more often.
Also happens to Red twice. First defeated by the Elite Four to the point everybody wonders if he died in the process and later when Deoxys defeats his entire team.
Out of the Five-Man Band of the Kalos region, headstrong and physically-capable Y tends to be knocked around the most. Justified as it is stated that she's stronger than Tierno, Trevor, and Shauna while X isn't likely to get into the fray unless he's being directly targeted, meaning that by default she will be the first to jump in.
Pokémon Origins: Articuno is one of the legendary bird trio, and is said to cause snowstorms just by flying overhead. Mewtwo shrugs off its signature Blizzard and oneshots it with Psystrike. Red is left shocked that not even a legendary Pokemon stood a chance against Mewtwo.
The Prince of Tennis: Team Fudoumine. The first rival team introduced, they were given an angsty backstory and were supposed to be serious competition. They wound up being this trope instead (first against Rikkaidai, then against Shittenhouji).
Ranma ½: Ranma, Ryouga, and Mousse get hit with this in the Pantyhose Taro and Musk Dynasty arcs.
In the first scenario, the aforementioned villain is looking for a specific visitor to the Jusenkyo cursed springs, and therefore ends up crossing paths with them and defeating them handily. Ryouga even goes as far as calling him a "demon" when warning Ranma about him. Justified, given that Taro turns into a giant, flying minotaur when splashed with water, while that same water turns Ryouga and Mousse into small animals, and Taro has no qualms about exploiting the hell out of this.
In the second one, Mousse is quickly dispatched by a warrior with a penchant for throwing knives, and Ryouga is turned into scenery by another warrior with strength even greater than his. Then Ranma himself is defeated by those warriors' lord, a Gender Benderki master.
In The Red Ranger Becomes an Adventurer in Another World, Red is a powerful warrior who treats even high-leveled monsters like small-fry. Because of this, he's often used as a measuring stick for an enemy's power level, and he struggles against the first Seed of Magic monster and Rosie to demonstrate how dangerous they are. He's also at the complete mercy of the monster controlling Akarina, which is able to constantly attack Red's blindspots to prevent him from fighting back.
Kuyou is on the giving and receiving end of this. In his first appearance, he curb-stomps Inner Moka and nearly kills Tsukune, forcing Moka to give the latter a Superhuman Transfusion to save his life, which also gives Tsukune just enough power to beat Kuyou down. When he returns during the Fairy Tale arc, he's averted Villain Forgot to Level Grind and gotten even stronger... but his only real purpose at this point is to show the readers how many levels in badass Tsukune has taken by kicking his ass.
During Season 1, Inner Moka always managed to defeat the Monster of the Week with ease, with a few exceptions; for example, she only managed to beat Gin because the full moon, which was Gin's power source, ended up being covered by clouds, and she was nearly killed by Kuyou. Come Season 2, she gets hit by this more and more starting with Kahlua, whom Inner Moka openly admitted she didn't stand a chance against.
The first sign of just how powerful Alucard is? Akua's Jigen-Tou technique barely slows him down.
Sanosuke Sagara was the first enemy to pose any sort of threat to Kenshin. He was superhumanly strong, almost invulnerable physically and wielded a BFS that would have made Cloud pull a muscle. His skills were so impressive he was worthy of becoming a regular cast member. Unfortunately for Sanosuke, he had to take second string to the title character. In a short time, it became a running theme that before an enemy could be considered a match for the Battousai, they first had to curb stomp Sanosuke. By the end of the series, the people Kenshin goes toe to toe with laugh in Sanosuke's face and for shear amusement smack him around in unarmed combat (which is supposed to be Sanosuke's specialty).
Probably the best example of this would be the introduction of Shinomori Aoshi in the anime, who knocked out Sanosuke down with one hit when Kenshin gave Sanosuke a beatdown which included a Ryu Tsui Sen, arguably Kenshin's strongest attack at the time.
This doesn't happen so much in the manga, where the only ones to brush Sanosuke aside are Jin-E, Shishio, and Saito, the last of which inspires him to undergo Training from Hell to catch up. By the end, Kenshin notes that Sanosuke has become so strong that he doesn't have to keep an eye on him in battle.
During one of the final arcs in the manga, Sanosuke is getting his ass handed to him while Kenshin does nothing but observe, a character tells Kenshin that he's truly heartless if he can watch his friend getting killed and not help him, to which Yahiko answers that, if it was anyone else (even someone Kenshin didn't knew) he would go help him without second though, but Sanosuke was the only one strong enough to not need Kenshin's help and because of that he was the only one suited to fight side-by-side with Kenshin.
In her early appearances, much is made of Sailor Jupiter's great strength and fighting prowess. Thereafter, naturally, her primary role in the series sometimes seems to be to take a beatdown from anyone the story wants to sell as being powerful and intimidating. The '90s anime adaptation mitigates it somewhat by giving her, like the other major characters, occasional focus episodes and depicting her as one of the very few senshi to more than once take down the Monster of the Week herself without requiring a finishing blow from Sailor Moon, but that doesn't mean she's not frequently knocked around by enemies and allies alike.
All four Guardian Senshi end up falling into this role in later arcs of the manga and especially in Sailor Moon Crystal. In the third season of the latter, their attacks stop having a visible effect even on monsters-of-the-week after the second episode, after which their role in the story is mostly to be outmatched by the enemy and require Sailor Moon or Sailors Uranus, Neptune, and Pluto to save the day.
Taurus Aldebaran devolved into this after his first fight, serving only to establish that the new antagonists could defeat a Gold Saint and were thus worthy of their place on the Algorithm. He ended up being killed offscreen in the last arc of the manga. At least he got a Tear Jerker and a delayed-effect Moment of Awesome out of it.
Even more ignominious: Shiryu's Dragon Shield, one of the strongest ever due to being submerged for millennia at the bottom of the holy Rozan waterfalls, is usually the first thing that cracks, splits, or outright shatters when he faces a new class of enemy.
Saki: The Kazekoshi team, which is the school to go to for Mahjong that boasts a massive lineup and a history of championships that was only broken last year by the Mahjong Demon called Koromo. They started the Finals with a massive lead over the opposition after Mihoko crushed everyone else in the first match without losing her gentle smile... then spent the rest of the finals bleeding away said lead as they proceeded to be every other school's punching bag, to the point where their representative in the last match spent most of her time there watching in horror as she gets stomped into the ground by everyone else. You know things are bad when their biggest moral victory during that period was that they managed to hold their lead against a complete beginner.
Samurai Champloo: Despite (or because of) his badass status, Mugen is hit with this trope. He nearly lost to Oniwakamaru (though he was drugged before hand), lost to the monk Shoryuu once, was defeated and nearly killed by spear specialist Sara and was unable to land a single blow on Big Bad Kariya.
Giroro chronically suffers from this. Fortunately, it's played for laughs.
Angol Mois, resident Destroyer of Worlds, suffers this a couple of times thanks to the introduction of Angol Stones.
Episode 133 features a rapid succession of heavy hitters going down for the count, thanks to Alisa Southerncross.
Tenchi Muyo!: In the manga, Ryoko's usually hit with this stick, though it's not uncommon to see Tsunami on the sidelines. For Ryoko, she's usually taken out during the first half of a major storyline but comes back weakened enough that she can't solve any of the problems on her own. For Tsunami, it's usually something that would put Sasami in danger.
Tengen Toppa Gurren Lagann: Viral is said to be the commander of one of the units of the "Human Eradication Forces." In the manga, he was the one who wiped out the Black Siblings' home town. However, he almost always loses against Simon, Kamina, or the pilots of the Gurren that day. Once his Heel–Face Turn happens, he gets better.
In the Century Soup arc, Toriko had a tough fight with Tommyrod. Even though he managed to cut off his hand and punch several holes through his body, Toriko ended up collapsing from his injuries, cold and exhaustion, unable to fight. However, when Tommyrod was right about to finish him off, Teppei showed up... and defeated him in a minute. Justified, since Tommyrod already was in really bad shape.
Nitros were introduced as terrifying beasts — Toriko and Zebra had serious problem with just one. However, in the Cooking Festival arc, Zebra easily killed three of them singlehandedly, and Jirou blew the head of one of them off with a flick.
The same thing happened with a Blue Nitro — even though they are insanely powerful, they usually get one-shotted.
Toriko was once worfed by an environment — the first time when he stepped foot in the Gourmet World, he was nearly killed by pretty much ewerything, even though he already survived several incredibly tough environments in the Human World.
Speaking of the environments, several of the harshest environments in the Human World, in which Toriko strived to survive in previous arcs, were completely demolished by the Four Beasts simply to show just how powerful they are.
In the battle between Toriko and horse king Heracles, the horse king simply snorted at him, creating a giant crater and destroying nearly a third of Toriko's body. Later, Toriko (regenerated with the help of cure water) unleashes his secondinner demon, which can withstand Heracles' snorts and deal damage to him. So Heracles inhaled, taking away all the air in the vicinity and instantly defeating Toriko.
The first encounter with monkey king Bambina turned out even worse — he defeated three of the Four Heavenly Kings during the time that took the fourth one to blink. And he wasn't attacking them — he just tried to dance and nearly killed them by accident.
Don Slime was created simply to be worfed — he was insanely powerful, was able to transform into pretty much anything, and claimed to be previous king of the universe. However, all his devastating attacks barely did anything to Neo, the Gourmet demon and he ended up defeated and eaten alive.
In fact, almost everyone who faces Neo suffers from it to some degree.
Transformers: Scramble City: Devastator, who is shown early on to drive off the entire Autobot army, is quickly taken out in a few shots by the Aerialbots. Later on, Menasor and Bruticus are driven off by the arrival of the new cityformer Metroplex.
Ultimate Muscle is another one of those series where every good guy except the main character seems doomed to lose every fight they get in. Dik Dik van Dik and Wally Tusket get a lot of Lampshade Hanging about their repetitive losses, but there's also Jaeger, whose ability is lauded far and wide... and who loses every single match he gets into. (Well, OK, he wins one, but that was where he was fighting on a team.)
Karin Yuuki of UQ Holder! scores a couple of early victories then continuously falters due to adversaries exploiting the weaknesses of her immortality. This actually gets lampshaded to her later on in the series, and she begrudgingly agrees.
Yakitate!! Japan: Kai Suwabara only seems to win Cooking Duels by default. Both times he went up against Azuma, he lost without even having his bread tasted.
Yu-Gi-Oh!: Monster Cards themselves are not immune to this either: when a duel is intended to show off a particular new card, an older and already established ace card will generally fail to do the job first, or be overpowered by an opponent's card effect. This does not exclude the ace monsters Dark Magician, Elemental Hero Flame Wingman/ Neos, Junk Warrior/Stardust Dragon, Number 39: Utopia, Odd-Eyes Pendulum Dragon, Decode Talker/Firewall Dragon, and Seven Roads Magician, who frequently found themselves or their evolved forms take a beating to set up showing off a new card.
In the first anime series, Kaiba fulfills this role, especially when he's in an Enemy Mine situation. He gets worfed by Pegasus in order to demonstrate how powerful his Mind Scan is, he gets worfed by Noah (though Noah cheated) to set up his duel with Yami, he's defeated by Dartz in his 2-on-1 duel with Yami, and in Yu-Gi-Oh! The Dark Side of Dimensions he gets defeated by the powered up Aigami on his 2-on-1 duel with Yugi.
Speaking of Kaiba, his Blue-Eyes Ultimate Dragon — established to be one of the most powerful dragons in the game, which even Yugi failed to take down — falls prey to this when Obelisk the Tormentor is introduced. The anime also has Obelisk No-Sell Mirror Force, which otherwise is a dangerous Trap Card because it wipes out every Attack Position monster on the field.
Also, in any series, when a character manages to pull off an impressive or game-winning combo on their first turn, you can count on them losing in the next turn. A good example is when Haga and Ryuzaki duel Siegfried. They both Summon their most powerful cards, Insect Queen and Black Tyranno... and then Siegfried defeats both of them by playing Walkuren Ritt. Similarly, one-off character Dr. Collector Summons five powerful Spellcasters and sets up a devastating mix of lock-and-burn that would make him invincible... unless his opponent, DD, played Destiny Hero Bloo-D, which he did.
Mai is a very good duelist and strategist and has won plenty of duels offscreen to make it to the finals of both Duelist Kingdom and Battle City but she has the misfortune of going against powerful and dangerous opponents such as Dark Marik to show the viewers how hard it will be for the heroes to win.
Manjoume gets the Worf treatment quite a bit — he's lost to Daichi, Amnael, Saiou, and Amon. All four of them beat Manjoume in their first shown duels, and with the exception of Amon none of them had a particularly hard time doing it. He also tends to duel Judai whenever Judai gets a new deck. He got more victories in Season 2 after his Face–Heel Turn, including against Daichi and Asuka, and he's the one who dueled and defeated the entire Obelisk Blue dorm. Season 4 gives Manjoume a significant victory when he defeats Edo. Averted in the GX manga. Out of a dozen shown duels or so, Manjoume only loses two of them.
You could probably say that both Judai himself and Ryo got this from Edo. (Judai did win his first duel against Edo, but even Judai was smart enough to realize that Edo had let him win. It was certainly the case in Edo's duel against Ryo; the only duel Ryo had previously lost was one where his opponent cheated.)
Edo himself suffers from this a little. After beating his stepfather [DD] and winning Bloo-D, he only gets one more win for the rest of the show. He loses to Light possessed Saiou to show how dangerous Saiou's powers under the Light of Ruin are. His only fully shown duel in Season 3 is to Amon to show how dangerous Amon's new Exodia deck is. And his only duel in Season 4 is against Manjoume who he loses to as well.
GX second-season Big Bad Sartorius duels Prince Ojin, a One Turn Kill specialist. Using a few cards activated directly from his hand (they're never even played to the field), Sartorius forces Ojin to OTK himself. Sartorius never even takes his turn; technically, he won in zero turns.
Toward the end of Yu-Gi-Oh! 5Ds, The Dragon, Aporia, having made a Heel–Face Turn after being inspired by the heroes, challenges his ex-boss, Well-Intentioned Extremist Z-One. Aporia is confident he can win, with the stakes being that Z-one calls off his scheme if he does, as he's seen what he believes to be his master's entire deck. Except Z-one thought he'd try something like this and deliberately avoided showing all his deck to his henchmen. The result? Aporia is fatally wounded and Z-one's Life Points are untouched. The pivotal moment of the fight is when Z-One's Timelord Metaion leaves due to its effect, and Aporia thinks he's won, because that was Z-One's big boss... but then Z-One reveals that he has ten main Timelords, and Metaion wasn't even a particularly strong one. He then summons a second, and promptly undoes Aporia's entire strategy.
Don Thousand does the same thing in Yu-Gi-Oh! ZEXAL against Mizael, arguably the toughest (or second behind Nasch) of the Barians. Mizael attempts to pull a Taking You with Me against Don Thousand which would knock out both of them, but Don Thousand manages to defeat Mizael seemingly by playing absolutely nothing. We later learn that he can manipulate his opponents' moves.
YuYu Hakusho does this with Kuwabara, who lost most of his battles in the Tournament Arc to show how terrible the next team was. Averted against Team Masho, where he beat their captain, and Team Toguro, where he beat Elder Toguro.
