Worf Had the Flu

""It was an opponent Nanoha-chan wouldn't have had any problem protecting her allies from or defeating if she had been her usual self. But the strain of overexerting herself made Nanoha-chan less capable, and her body slowed down at a crucial moment. The result... was this.""

- Shamal, Magical Girl Lyrical Nanoha StrikerS

A type of fandom-based Author's Saving Throw, this is the specific rationalization that a character suffering from The Worf Effect or a Curb Stomp Battle did so only because something (artificially) undermined their performance. The insinuation, of course, is that it probably wouldn't have happened this way under "normal" circumstances.

This is often used within fandom, and can be a satisfying answer for fans bothered by the outcome of the battle or use of the trope itself. As the 'flu' is generally pulled from something within the story, explicit or otherwise, it does not necessarily require a blatant Retcon or Canon Discontinuity—the event itself is still treated as canonical. Note, however, the new reason may not officially be, except as a passing Ascended Fanon by some writers.

Whether or not a later matchup is provided becomes irrelevant. If enough ire is raised from using the Worf Effect, a later matchup may be specifically avoided to dodge any mention of it at all. On the other extreme, the response to the trope may be too loaded with Take That overtones not to come off as petty. In contrast, a well-written Evasive Fight Thread Episode often includes 'flu' logic in an effort to quell any complaints about the match-up. Essentially the "Power Seep" part of Power Creep, Power Seep.

This Flu is also often exploited by a nasty Big Bad Wannabe in order to have a shot to kill those powerful people, through luck mostly. Of course, defeating those who had flu doesn't mean you are that trope. With planning and exploiting this 'Flu', one can avoid being labeled of that trope.

A type of Drama-Preserving Handicap. Compare Actually a Doombot.

Anime and Manga

 * In Bleach, Ichigo's poor performance in his battles against Ulquiorra and Yammy, as well as his first battle against Grimmjow, is attributed to his difficulty suppressing his inner hollow.
 * In the Arrancar arc, Hitsugaya, Rangiku and Renji are losing to their Arrancar enemies, but then they get permission to release their Power Limiters, and easily defeat their foes. Being limited to 1/5 of one's power is a pretty crippling handicap.
 * Ichigo when confronted by the #5 Espada Nnoitra Jiruga gets easily owned, then gets bored and leaves the ass-whooping to his Fraccion, Tesla. It should be noted that Ichigo had a grueling battle against #6 Espada, Grimmjow Jaegerjaquez (who also got owned by Nnoitra) in which he barely defeated him. This is shown when he took on Ulquiorra again, and was a match for him, until he had to release (Ulquiorra lost, but Ichigo doesn't consider his Super-Powered Evil Side laying the smackdown on him a fair fight).
 * The entire Bount Arc is this trope. Every Soul Reaper who comes to Earth can only use a fraction of their power, and Ichigo has to relearn Bankai for some silly reason. Even the Bount enemies don't reach full power until they travel to the Soul Society.
 * In the Invasion Army arc, Ichigo's power was failing after . So of course he was coming into this new dilemma already handicapped.
 * In the Lost Substitute arc, it's revealed
 * In the anime Berserk, Casca actually loses and needs rescuing from her first battle with Adon Corbowitz. While tending to her Guts notes blood between her thighs and comments to himself how it must be hard for a woman mercenary. The next time she and Adon meet, the beatdown goes the other way.
 * It's also a Chekhov's Gun, as she's seen being 'out of it' earlier. Furthermore, as in case the viewer doesn't get it, Adon says, when being beat down: "YOU HAD PMS!?"
 * One Piece: Luffy and the rest of the Straw Hats are initially unable to defeat the CP9, and while they are not yet using the techniques they use to defeat their opponents in later battles, Nami suggests that they weren't fighting at their full potential because they were still unsure whether Robin had betrayed them. Once they realize that she did what she did for their sake, they are able to fight to their full power to rescue her (Strangely enough, Sanji knows Robin's reasons and still is unable to defeat Blueno, but later defeats the far more powerful Jyabura). Luffy also admits he wasn't at his fullest because he wasn't full and just fought Wanze, whow as a relatively weak enemy but managed to thrash Sanji a fair amount before he started using knives.
 * Earlier in the manga, Sanji was wounded by Pearl and nearly lost to Gin.
 * In the Skypiea arc, Luffy, Zoro and Sanji are unable to fight well against Wiper because they have not adapted to Skypiea's higher elevation and thinner atmosphere. Luffy manages to get over this by the time he fights the White Berets, and throughout the rest of the arc, there is no suggestion that the characters are fighting at anything less than their full potential.
 * The Straw Hats exhaust themselves fighting the first Pacifista on the Sabaody Archipelago, making them easy pickings for Sentoumaru, Kizaru, Kuma and another Pacifista. To be fair, though, if they had that much trouble against an ordinary Pacifista, they had little chance against the original model with Devil Fruit powers or an Admiral. And with the possible exception of Luffy, they were all also recovering from the fight against Gecko Moria, his generals, Oz and the subsequent beatdown by Kuma. Especially Zoro.
 * Kuma seems to be a fan of this trope, considering that he's beaten the Strawhats twice, and both times he confronted them right after they'd fought a major, exhausting battle.
 * Luffy's somewhat underwhelming (Haki aside) showings during the Kuja and Marineford battles are at least partially attributed to having to deal with the Kizaru/Kuma/Sentoumaru/Pacifista gangstomp the day before in the previous case and nearly dying against Magellan and being kept running on sheer willpower and hormone doping in the latter case. Of course, a lot of it has to do with the fact that the major players are all Warlord of the Sea class, at least, but the Luffy at Marineford didn't seem to be operating at the same caliber as he did against the likes of Rob Lucci and Gecko Moria, and actually had to be doped again near the end of the battle.
 * This was the primary reason Franky was struggling against Fukurou, despite having previously overpowered Blueno; As he was lacking in Cola, his attacks were decreased in effectiveness and power. Once he got his cola back...
 * Seriously, many of Zoro's battles had him at some sort of disadvantage or not at his full potential. In the battle with Cabaji, he was already injured from Buggy's earlier attack. When fighting Hachi, he was still recovering from his wounds from his fight with Mihawk and had a fever on top of that. He had difficulty with Mr 1 since Mr 1's body can become steel, something Zoro couldn't cut at the time. During the Davy Jones game, he wasn't able to use his swords due to the rules. He only had two swords with him during the fight against Ryuuma. And against Oz, he was still getting used to his new sword Shunsui. With Kuma, he had taken damage from Ryuuma and Oz over the night. With the Flying Fish Riders and with the Pacifista, he was hampered down from his injuries from Thriller Park, along with Luffy's pain that was transferred to him.
 * One scene in Episode 52 of the Naruto Shippuden anime (which doesn't appear in the manga) suggests that Naruto and Sakura fared poorly against Sasuke in their first meeting with him after the timeskip because of their wounds from their previous battle (although they do realize that Sasuke has gotten far more powerful). Yamato is also holding back, not wanting to injure Sasuke too much, but just after he decides to get serious, Orochimaru leaves with Sasuke.
 * In the manga, Naruto was still suffering from his Four-Tailed Form's side effects. He was, at best, half power when he finally encountered Sasuke (even Orochimaru commented when they fought again, Naruto wasn't doing nearly as well before). Sakura, likewise was still suffering from the poisonous wound that she had gotten from the KN 4's tail swipe. Only Yamato and Sai were at full strength.
 * Before the Time Skip, during the Chunnin exam tournament, Jiraiya notices the chakra-blocking seal that Orochimaru had placed over Naruto's Kyubi-containing belly-button seal, and realizes it prevented Naruto from channeling properly. Once he removed it, Naruto was able to instantly master the water-walking technique he had been struggling with before. And it might also explain Naruto's rather lackluster performance against Kiba—Naruto previously never needed any distractions or significant pauses in a fight to create Shadow Clones. Of course, Naruto himself never seemed to notice his own difficulties...
 * Tsunade's first appearance has her using then-current Big Bad Orochimaru like a paddleball. The only reason Orochimaru did not bust out far more powerful moves for the fight was because had previously lost the use of his arms (and thus, most of his jutsus). Jiraiya was likewise disabled thanks to a drug Tsunade slipped into one of his drinks earlier on. Tsunade as well suffered some early damage due to her entirely psychological weakness to blood, making her use her trump card on a healing power. If the Sannin were at their top form during the fight the others there would've been useless and the battle would've dwarfed even the epic rumble that it was and likely not be quite as one-sided.
 * Missed Moment of Awesome...
 * The Sound Four were all capable of holding off multiple ANBU agents in their first appearance, but all lost to genin later on. However, this (and the fact that the genin caught up to them in the first place) was at least partially because they had exhausted themselves when they ran into two Konoha jonin and had to activate their cursed seals just to get away.
 * Sasuke outright admitted he was only capable of beating because of the very sickly state he was in when he attacked him.
 * Played with in Sasuke's battle with
 * To be fair, Sasuke did far better than Itachi even suspected he would. Breaking Tsukuyomi, equalling him in Taijutsu, faking out Amaterasu... only Susanoo Sasuke didn't have a contingency against since he had never seen, or even heard of it before. And that was the only part of the fight that Itachi let Sasuke win in.
 * Pain versus Naruto could have been much more one sided with the odds heavily against Naruto had it not been for the fact that Pain was trying to capture Naruto, not kill him. It also didn't help that he'd just finished fighting and leveling a village, and his most powerful body had its powers disabled at the start of the fight.
 * And Chapter 485 seems to be setting this up for the fight between In this case it's less Worf Had the Flu and more like leveling the playing field, as  It still counts since
 * And going back allllll the way, Naruto's crappy abilities with chakra control are implied to be due to the Kyuubi's chakra inside him. Once he started getting his jutsu under control, he was learning jounin level skills (albeit in a wasteful manner—thank the Sage of Six Paths that he's got enough chakra to burn) and a technique that requires a practically impossible level of chakra control.
 * Dragonball Z:
 * Goku's heart virus thing while fighting Android 19 in This is actually taken to the extent of an Alternate Universe, where without the aid of Trunks, Goku died from the virus, and well... While Android 19 was indeed programed with the intent to counter Goku's fighting style, it was made clear he would never have stood a chance had Goku been at full health. Made clearer when, after defeating Goku, he gets cocky and  tries to take on Vegeta. Seeing as Vegeta does not have any illness, uses a completely different fighting style, and has undergone three years of Training From Hell to prepare for this very day, it's  easy to predict how it goes for 19.
 * Also happens much earlier when the series when Goku is defeated by Yamcha because he is extremely hungry.
 * Also happens when Goku loses to King Piccolo's minion Tambourine, but only because Goku was exhausted from fighting in the Tenckaichi Budokai. Tambourine is confident he can win again in the rematch, but things don't go so well for him.
 * Lordgenome of Tengen Toppa Gurren Lagann
 * Even more true considering
 * Similar to the Super Robot Wars example further down the page, Mahou Senki Lyrical Nanoha Force gives this treatment to by way of depriving her of the equipment needed to fight against the Huckebein.   goes into her battle with Cypha lacking the countermeasures necessary to neutralize her opponent's Mage Killer abilities, and as a result only manages to hold her own until Cypha gets serious. Double points here because before this, Signum had never been defeated onscreen by any of the other characters.
 * Nanoha's overexerting herself resulted in her getting injured and almost crippled while on a mission, as Shamal points out in the above quote.
 * The Wolkenritter are less at an advantage over Nanoha and Fate's group because they have sworn not to kill anyone in their quest to save Hayate. Despite managing to fight off Signum until she retreats or outside forces interfere, Fate loses most of her sparring matches against Signum in the period after A's.
 * Prior to his first battle with Mukuro, Hibari from Katekyo Hitman Reborn literally had been injected with a flu, causing him to get curb-stomped despite being at least Mukuro's equal in fighting prowess.
 * Ash's Grovyle from Pokémon evolves into Sceptile...into the worst possible moment, when he was heartbroken. Somehow, this causes Sceptile (a powerful Pokémon in its own right) to be unable to use its attacks, rendering it useless for a couple of episodes.
 * Ash's Pikachu gets a taste of this in the very first episode of the Unova saga. overloads Pikachu's electricity-storing capability and thus renders it unable to use Electric-type attacks. Ash finds this out the hard way when the 'Chu gets trounced in a battle with a trainer who had, mere minutes earlier, received his first Pokémon.
 * "Charizard Chills" has the title Pokémon critically frozen after battle with a Poliwrath. His respect as well as loyalty for his trainer returned after Ash spent all night trying to thaw him out.
 * Later, he also suffers a wing injury during the battle against the Johto gym leader Faulkner, giving him a little bit of trouble against the leader's Pidgeot.
 * Digimon Savers: In one episode, one of Masaru's punches breaks SaberLeomon's tooth. This wouldn't be out of character for him except that an earlier attempt to punch SaberLeomon had significantly less effect, and prior to the second attempt SaberLeomon had just taken a Gizumon blast, severely weakening him to the point when an Ultimate level Digimon could blow him up.
 * In the Tales of Symphonia manga, Lloyd claims that lost his last fight with him because he was still suffering from the wound he received.
 * In Tokyo Mew Mew, Ichigo gets attacked by Kisshu in Episode 17 while she's sick, resulting in her being unable to defend herself and the Blue Knight appearing for the first time to save her.
 * Muhyo and Roji's Bureau of Supernatural Investigation takes a long time to recover his tempering after a sentencing, so when a problem arises soon afterward, he's often unable to intervene immediately. As such, after the group defeats Face-Ripper Sophie, only for, they spend much of the battle retreating, and must brew Muhyo a dangerous potion to help him get his tempering back before they can effectively fight back.
 * In Tegami Bachi, during the infiltration of Honey Waters, Niche drinks some of the poisonous water that is the village's namesake. It doesn't take effect immediately, but when the villagers pin down Lag and Connor, Niche is only able to defeat Lag's attackers before being paralyzed from the poison, resulting in her and Connor being captured and Lag barely escaping.
 * Rurouni Kenshin: One of the reason Kenshin easily fell to Shishio  was because he had already gone through battles with Aoshi and Sojirou. Both opponents were considered near or at Kenshin's level, so it would be a miracle for him to even be able to stand up to Shishio. This trope extended to Kenshin's allies as well; Saitou, Sano and   were unable to even hurt Shishio due to their previous injuries.
 * Shishio is actually concerned about whether or not this is fair, but Kenshin reminds him that it counteracts his own handicap, his lack of sweat glands which eventually . Shishio also plays with the trope, since it's implied that the extra heat energy his body produces makes him stronger somehow and he can literally kill someone by touching them long enough. Oddly enough, he doesn't use this as a weapon.
 * Medaka Box: Zenkichi's victory against Munakata is slightly downplayed, as despite his abnormal desire to kill,.
 * Soul Eater: Black Star's failure to use Soul Menace against Kid is actually a product of his inability to deal with the worfing that he's noticed he was being subject to. And THOSE losses were caused by him losing confidence in himself for not being able to master Shadow Star.
 * In Gundam Seed Destiny, when Athrun brought up how Shinn had defeated Kira, Kira admitted to being "distracted" because he was "unsure" if he should be fighting ZAFT or not.
 * Inverted in Hunter X Hunter where Gon (the main character) barely beat Shizuku in a right handed arm wrestling match. Then when Shizuku goes back to her friends we learn that Shizuku is left handed.

Comic Books

 * In the big DC vs Marvel Universe crossover, one fight that attracted particular opprobrium from fans was Lobo—a character who can go toe-to-toe with Superman and at the time could regenerate from a single drop of blood—losing to Wolverine (who at the time didn't even have his adamantium skeleton, though his healing factor was significantly boosted as a result). This was explicitly down to Popularity Power—the results were voted on by fans—but the match-up was so uneven the writers had to have Wolverine's victory take place off-panel. A little while later Lobo mentioned that he'd actually been bribed by "some bald guy" (presumably Professor X) to take a dive in the fight.
 * One of the more famous events in the history of the X-Men is the battle for leadership of the team between Cyclops and Storm - who at the time had no powers. Storm won by stealing Cyclops' visor. Without the control of the visor, any attempt to continue fighting would've run the risk of killing Storm (or any of the audience), so he gave up. Several years later, Cyclops' ex-wife Madelyne Pryor announced that she'd used her psychic powers to make Cyclops lose. This is a relatively easy Retcon since Cyclops spent much of the fight distracted by a major argument he and Madelyne had just been having, so to say he didn't exactly have his mind on the battle was very easy to change into a result of Madelyne's direct influence.
 * Played in advance in the Superman vs Predator mini-series. Under normal circumstances the Predators would have posed no threat whatsoever - so the story had Superman catch alien flu just as he arrived in the jungle where they had landed.
 * A better explanation happened in Superman vs Aliens. The battle took place on a planet circling a red star, and since Superman's might mostly comes from the radiation of a yellow star...
 * And when Superman fought Muhammad Ali, the aliens behind the Let's You and Him Fight had made sure it was under red star radiation.
 * Several defeats and cases of Badass Decay, of villains who were revealed to be members of The Intelligencia in Fall of the Hulks were explained to be staged for heroes as distractions from their true schemes.
 * Early in his superhero career, Spider-Man is actually beaten and unmasked by Doctor Octopus in front of his friends and family. However, Peter's powers were on the fritz at the time—he had lost his spider-sense and had his strength reduced to that of a normal teenager—and so no one believed that he was actually Spider-Man, but was just dressing up as Spidey in order to distract Doc Ock. Much later, when Peter revealed his secret identity to the world during the events of Civil War, Doc Ock went ballistic because he had known this information for years and never realized it was the truth.
 * A borderline case occurs with the death of Gwen Stacy, as Spider-Man was suffering from an unspecified illness at the time. This tends to be omitted in almost all retellings of the story, however; given that Gwen's neck snapped due to the abrupt stop from Spidey's webbing, it's questionable whether the illness was a factor at all in her death.
 * In the very first crossover between Superman and Spider-Man, Spidey initially holds his own because Lex Luthor and Doc Ock had unknowingly (to him) sprayed a dusting of Kryptonite particles on him. But once those particles come off... well....
 * In another meeting between the above two it was a blast of Red Sun Radiation. Spider-Man does well until the radiation fades just as Superman is about to use a full powered punch (this is the 1970's Superman.) He stops the punch and the blast of the punch knocks Spider-Man through several buildings.
 * If the above two entries are referring to the first Superman vs Spider-Man tabloid, they're both wrong in the fine details. Spidey's ability to hurt Superman in their "meet-and-greet" battle was due to Luthor using a Red Sun Radiation beam on him, thereby at least partially negating Supes' invulnerability. Superman still had his full strength, though, so once he recovered from the shock of being knocked around by Spidey (who, let it be said, was almost as surprised as Superman when a blow sent the Man of Steel flying), he struck back, only to realise while his fist was in motion that if the punch landed, it would kill Spider-Man, so he pulls the punch—with the resulting wind-blast mentioned above. After Spidey recovers from being sent flying through at least one building, he gets angry and charges Superman, only to have the Red Sun Radiation wear off just as he lands his first punch. As he puts it a couple of panels later, "Oboy. I broke my hands..."
 * Similarly, The Flash, when in the Marvel Universe during the JLA-Avengers crossover, was unable to run as fast as he usually does (and, eventually, loses his Superspeed altogether) because 616 lacks the Speed Force. Otherwise he'd probably knock every Avenger not named Thor unconscious about .5 seconds into the required "Crossover Fight".
 * "It was just a Doombot." Really!.
 * Thanos can make duplicates of himself perfect enough to fool the Watcher. (Which brings up the question of what's the difference between beating Thanos and beating a perfect copy of Thanos.)
 * ...and then she beat him again!
 * In Knightfall, Batman begins with an unspecified illness and the plotline is based around how he completely wears himself out by trying to capture all the inmates the Dangerously Genre Savvy Bane has released from Arkham, positioning himself for the Curb Stomp Battle Bats will eventually receive.
 * Doctor Strange lost to Hulk during World War Hulk because he was channeling the powers of a demon that was too powerful for him to properly control, and because the Hulk tricked him and broke his hands to prevent him from properly casting spells.
 * When Doctor Strange helped found the original Defenders, his immune system apparently took a vacation. The writers admitted to brainstorming "how do we keep Doc from wrapping up the plot in one frame" almost every issue. Lampshaded when Doc took a break from the Defenders to figure out why he was having so much trouble with his spells.
 * Similar to the eternal Doombot excuse, Prometheus explained his embarrassing performances since his first, when he took on the entire Justice League of America, by explaining that in the intervening time someone had stolen his gear and impersonated him.
 * Retroactively done to every single Superman vs. The Flash race. Superman tries to convince Barry Allen not to return to the speed force and states that he's been able to keep up if not win in all their races. Barry simply tells him, "Those were for charity, Clark." Fastest man alive indeed.
 * The above was an odd case of this. Superman really was about as fast as Barry back when those issues were actually written, but Superman was powered down substantially in 1986 and, even if a lot of that power has returned he is not back to Silver Age power levels, so when those Silver Age stories became canon again, this explanation became necessary.
 * Thor is said to only use about a fifth of his full strength when fighting humans, even insanely strong ones like the Hulk, out of fear of accidentally killing them. One of the few exceptions (he specifically noted he wasn't holding back) was when he fought Iron Man after Civil War, and even after Iron Man's numerous upgrades in the past few years Tony didn't last thirty seconds.
 * When Supergirl first returned in 2004, she was shown outperforming Superman to the point where it was speculated that she might actually be more powerful. It turned out, this was meant to show that Superman had been holding himself back all these years out of fear of causing death or destruction (which Supergirl in fact does in the early issues because she doesn't know her own strength.)
 * So when the yellow-clad Weapons Master does fight the flu-ish Superman, this ironically makes Big Blue that much more dangerous. As he tries to explain to the bad people, he doesn't know if he can stop his punches from taking off heads.
 * In one Bronze Age story, Superman starts having Does Not Know His Own Strength moments, and fears his powers are growing beyond his ability to control. In fact, the reverse is true: the Parasite is slowly draining his powers, but he made a point of first draining Supey's sense of self-control that normally keeps them in check. Since he was no longer pulling his punches, they seemed more powerful even though his baseline strength was actually dropping. By the time he figured it out, the Parasite had already drained a good chunk of his energy.
 * Preacher (Comic Book); the flashback history of the hero's dad. All sorts of horrific things end up happening to Daddy simply because his army buddy was too damned stupid to go get the flu treated.
 * When Erik Larsen subjected the Incredible Hulk to The Worf Effect at the hands of new, improved Doctor Octopus, Peter David, who had been writing Hulk comics at that point, wrote him beating Octopus with two fingers, saying that last time he simply "had a bad day".
 * An issue of New Avengers had Wrecker narrating a fight between the titular team and The Hood's crime syndicate, explaining that he wouldn't have lost to Luke Cage, Hero for Hire, who is significantly weaker, if Doctor Strange hadn't confused him with his magic.
 * Hulk was on the receiving end of a Curb Stomp Battle at the hands of Zeus. That wasn't because of this; rather, that battle was the flu to set up for the next story arch, which required the Hulk to be significantly weaker than his powerlevel at the time normally allowed.
 * In Wolverine Origins, Dog only attacks James (the future Wolverine) after James exhausted himself cage-fighting during the previous night. Dog had also slipped one of James' opponents a set of brass knuckles to make sure James would be injured even worse. And James still nearly kills Dog after Dog makes him remember that
 * Rachel Grey aka Marvel Girl of the X-Men was the host of the Phoenix Force for a long while. Her relatively weaker power compared to her mother's stint as the Phoenix's host was due to Rachel actively suppressing the Phoenix's power. She mentioned at one point that she only allowed the Phoenix to use at most one percent of its power.

Film

 * It's ironic this trope is called Worf Had The Flu, considering how often it happens to the Starship Enterprise itself. For instance, in The Wrath of Khan, the rather puny-looking Reliant sneak attacks the Enterprise and leaves the ship hobbling along for the rest of the movie, thus prolonging a confrontation that, under normal circumstances, would've resulted in the Enterprise mopping floors with the Reliant within about two minutes. Most of the crew being cadets didn't help, and Khan was Genre Savvy enough to have studied the Enterprise in detail.
 * This is also used to explain why a jury-rigged Enterprise in the following movie The Search for Spock goes down with one hit from an old clunker Bird-Of-Prey.
 * Later, the far more advanced Enterprise-D almost gets blown out of space by an even clunkier Bird-Of-Prey in Star Trek Generations, thanks to the Duras sisters getting their hands on their shield frequency (which apparently lets them fire through it).
 * In the same film, the Enterprise-B was so new most of its equipment wouldn't be in until Tuesday, and was only being taken out for a spin for the sake of the news crews. Also, it turns out that Earth, the main planet of the Federation, had no other available ships, leaving the Enterprise as the only one in the sector, because... uh, because... um...
 * In Hellbound Hellraiser II, many fans were disappointed to see Series villain Pinhead and his cronies taken out by the new Cenobite, Dr. Channard. Many have written off his easy defeat due to him being weakened and disoriented by learning he was once human, a notion supported by Hellbound screenwriter Peter Atkins.
 * The Iron Man films do this. The first has
 * Predators does this when

Literature

 * In the fourth Riverworld novel The Magic Labyrinth, master swordsmen Cyrano de Bergerac and Sir Richard Burton take time out of a running battle to fight a (rematch) duel. Both are itching to see who's better, but they're both weary from battle, both slightly wounded, and have both been drinking to boot, and they're on a rapidly sinking ship (they really wanted this rematch). In the end, Burton draws first blood, and offers to help Cyrano to his feet... only for Cyrano to be shot by one of Burton's companions, who had no idea the duel was a gentlemanly one. Burton later (and during the fight too) wonders what the fight would have been like had they both been at their peak condition.
 * In Brisingr, Paolini has made certain that Eragon has not had time to recuperate to his full strength since achieving his super-human power.
 * A more straight example would be at the end of Eldest, when However, this was subverted when Eragon
 * In Men At Arms Lance-Constable Cuddy brags in one scene about his axe-throwing prowess; he's so good that he won the last contest he was in by a landslide, aiming at a target behind him, while he was sick with a bilious attack. Right now he's healthy as a horse. So don't mess with him.

Live-Action TV

 * The trope naming incident occurred in an episode of Star Trek: The Next Generation but wasn't an example of this trope. Worf, the badass Proud Warrior Race Guy, keels over in the middle of his shift right at the end of the episode's opening teaser. In this case, it was a Pseudo Crisis; the show comes back from commercial-break with Worf already all better after a simple inoculation in sickbay, being lectured by the doctor about he should have been vaccinated when he was a kid.
 * Episode six of Dollhouse features this canonically on both sides: when Ballard and Echo fight, on the surface it seems like it might be an even match that could go either way. Echo with her programming is probably the better technical fighter, but Ballard is very big, built like a brick house, and so tough he can take out four gun-wielding thugs with a plank after he's been shot—plus, he's a trained fighter, so all of his experience is real. However, he had been shot mere days ago, and was not looking to actually hurt Echo, as she's his best link to the case. Cue him fighting defensively and eventually getting worn down. On the flip side, Echo was also fighting in order to frame Ballard for shooting a cop, not to actually win, so while she wasn't fighting to win either, her goals were served by simply getting him to the right place at the right time and disappearing.
 * Spike's attempted rape of Buffy the Vampire Slayer in "Seeing Red" only got as far as it did because a run-of-the-mill vampire had got a lucky shot in earlier (as she was staking him, no less). Both injuries carry over into Buffy's fight with a superpowered Warren - even with super-strength and near-invulnerability, he can tell she's off her game.
 * On Angel, Hamilton stomping over Illyria happened only after she had been massively depowered, and it's probably telling that Hamilton didn't go anywhere near her until this had happened, and in fact when Wesley was studying her gave him a hint that led him to discover how to drain her powers. He even goes into an exaggerated Smug Snake routine to Illyria's face as he ponders why she can't beat him to a pulp.
 * In Dai Sentai Goggle Five, only going as far as episode 8, Goggle Blue gets A Day in the Limelight episode...where he got horribly owned solo by the Monster of the Week because they managed to wound his leg while protecting a woman. Skip ahead several episodes later and then, he's shown to be as good as he gets when he's on a solo fight. Especially when kids are involved.
 * An inversion takes place in Mahou Sentai Magiranger, where the Heavenly Saint Lunagel is defeated in battle by Wolzard partly because she went on her own, but mostly because he'd spent the past four episodes doing nothing but powering up.

Professional Wrestling

 * After coming to WWE, The Big Show was rather horribly misused, ending up as a lower midcarder holding the Hardcore Title. About this time, Brock Lesnar had pretty much obliterated his way to the World Title. Deciding to make Show the next challenger for the belt, WWE bookers just cooked something or other up about "don't wake the sleeping giant", basically saying that the reason Show had been so low on the cards was that he hadn't been trying very hard to do otherwise.
 * May have been a Real Life dig at Paul Wight, who had been "fat-camped" down to farm territory OVW in the past for perceived shortfalls in dedication (and diet).

Video Games

 * This happens at the start of some Metroid sequels. Samus loses all of her equipment or has something happen, to justify the player having to collect what Samus had at the start of the game. Also, in Metroid Zero Mission there is a sequence at the end which embodies this trope.
 * In Chrono Trigger there is a sequence where your party has all of their money and equipment taken from them. Unless you have in your party, this sequence becomes a stealth mission.
 * In Prototype, halfway through the game Alex is given a "cure" that zaps him of all of his powers besides his strength, speed, and shapeshifting. He gets better.
 * In Super Robot Wars Original Generation Gaiden, many people seems to come to term that Lamia Loveless was hit with this trope that she accidentally got hit by so many Distress Balls. She only got caught by the Bartolls on the first place because she was not in her mecha (the same goes to Kusuha, Arado, Seolla and Latooni), and later on, Juergen managed to 'kill' her because for the same reason, added by the fact that she was just recently and forcefully been plugged out from her cockpit that binds her. She doesn't really have much impact after being rescued, but should you bring her to battle against the Bartolls in Chapter 34, she will express disgust on the Bartolls and show them that in the right conditions, they are no match for her. Unfortunately, however, she could never do it on Juergen (nor that she has any special lines against him when they face off in Free Battle).
 * In Golden Sun, when the party faces Saturos on the roof of the Mercury Lighthouse, they are able to defeat him. However, Menardi reveals that because he's a Fire Adept, he's weakened by being on the Water-aligned lighthouse roof (strangely enough, although Water Adept Mia is able to recover her MP, Fire Adept Garet suffers no disadvantages). Saturos is stronger (and backed up by Menardi) when fought on the complementary Earth-aligned Venus Lighthouse.
 * The first Yellow Squadron member shot down in Ace Combat 4, Yellow, is revealed to have sortied with poorly-maintained engines.
 * In Zero Gelb 2 mentions that his squad would often be sent from one mission to another without even any basic maintenance on their planes. The result is a slightly easier Ace fight.
 * Given the power levels of many Touhou characters this trope is used by many fans to explain the defeat of certain characters, since everyone in Gensokyo is battling under the Spellcard system, and if they weren't Holding Back the Phlebotinum, the fighting between magicians, time-stopper, ancient vampires, embodiments of death and afterlife, immortals, wielder of NUCLEAR POWER, and assortments of gods would have wiped Gensokyo off the map. And Yukari would pretty much beat everyone.
 * In Warriors Orochi, this is how the Orochi beats the Tokugawa. They arrive and launched their attack on Edo castle just in time when Honda Tadakatsu is away scouting the area. Considering Tadakatsu is often considered Samurai Warriors' Lu Bu, the battle might have a different outcome if he is ever present.
 * In Street Fighter, Birdie uses this as the actual explanation for his loss against Ryu when they meet again in Street Fighter Alpha; it also explains why he was white in the first game.
 * In Mortal Kombat vs. DC Universe the effect that causes the two universes to merge also evens out the power levels of the characters. Or else Liu Kang fighting Superman hand-to-hand would just be silly.
 * Archer is possibly the most powerful character in Fate/stay night, but he is handicapped somehow in almost every fight he takes part in.
 * Fate route: At the start of the route Archer is surprised and grievously wounded by Saber, who he didn't particularly want to fight. He is then sent against Berserker, who can ignore everything but his most exhausting attacks.
 * Unlimited Blade Works route: Archer spends most of his time trying to manipulate events rather than fighting (on the two occasions he does fight, his enemy runs away after one attack). After this, he is cut off from his source of mana and his power fades until he's only keeping his body together through sheer willpower.
 * Heaven's Feel route: Archer is wounded by Saber as in the Fate route, then is forced to fight in poor conditions and exposed to attacks which ignore his usual defences.
 * Lancer gets this too in the Fate route. His only accomplishments were fighting Archer to a standstill and attempting an instant-kill attack on Saber which failed...until you realise that this was before Archer was injured, Lancer was ordered to scout his enemies rather than defeat them, and . He is notably more Badass in the Unlimited Blade Works route.
 * Then there's Rider having a limited mana supply and not wanting to obey her Master's commands until the Heaven's Feel route, and refusing to wear his armour against someone he viewed as an inferior opponent... really, this could be applied to most characters in the game at some point.
 * In all routes, Saber starts out being improperly summoned by someone who can barely use magic, so she has an incomplete connection to his mana and therefore has to recharge herself very often with large amounts of sleep and food, even if she uses only a little bit of her power. This is exacerbated by the fact that she took a cursed, slow-healing stab close to the heart soon after being summoned. It also doesn't help that, due to worries that Shirou's lack of mage skill would leave him open to mind magics, she doesn't let him know her true identity and holds off on using her Noble Phantasm even more than any other Servant. And of course, her Master being unwilling to risk her life if he can avoid it and being unwilling to fight as ruthlessly as possible is a pretty hefty handicap for a Servant of the Grail War as well, even though she herself isn't really all that much more ruthless than he is (especially compared to all the non Rin and  Masters). The other Servants aren't pushovers by any stretch of the word, but as the two times she got a competent mage as a master showed, there is a REASON she's considered the strongest class.
 * The Fate/stay night Worf character, Berserker, has this arguably crippling him in UBW and definitely doing so in HF. In UBW, he's hampered in his fight against because he's shielding Ilya as well (which is given a Shout-Out in one of his Fate/Unlimited Codes missions, where he has to fight his opponent while keeping the defenseless Ilya alive). In HF, he gets hit by a gamebreaker ability he can't actually fight against  before he can truly fight. While in, the fact that he  is likely because all his stats had degraded...including Noble Phantasm, meaning God Hand no longer provided as good protection. And while the Berserker class amps his already legendary strength and speed, it leaves him unable to use any of his skills or non-auto Noble Phantasms, instead fighting almost purely on instinct, reflex and power. Which is enough to make almost everyone who encounters him wet themselves in terror.
 * Arcuied is operating far below her normal power in Tsukihime, as she is still recovering from Shiki slicing her into pieces, and has to devote almost all her strength to suppressing her bloodlust. This is probably a good thing for the sake of the plot, though, as with access to her full abilities, she has Story-Breaker Power and would curb stomp everyone in about ten seconds flat.
 * During the Duel to the Death between in the World of Warcraft novel The Shattering Prelude to Cataclysm,  gets some good hits in on, but after taking a hit from his opponents weapon, which unbeknownst to either of them, was poisoned, slows down long enough to take a fatal hit to the neck.
 * Zeus pulls this on Kratos in God of War 2 by tricking him into using a magic sword to defeat a giant statue at the start of the game. However Kratos had to deplete all his energy in doing so making him easy pickings for Zeus to kill him. As the end of the game shows though, Kratos at full power is more then a match for Zeus.
 * The statue's outstretched hand slamming into Kratos while his back was turned didn't do him any favors either.
 * In Mass Effect 3, this is the only reason why Cerberus agent Kai Leng is able to defeat . He puts up an impressive fight, but tends to leave someone not quite at their best.
 * , however, get's the last laugh, as Kai's main mission was to assasinate someone else, which had failed because, as

Web Comics

 * In one Sluggy Freelance strip, Zoe kicked resident Badass Killer Rabbit Bun-Bun through a wall. When Zoe brings this up years later to try and intimidate Bun-Bun, he responds, "That was then, and you were half naked. Let's rock."
 * In The Order of the Stick, Knight Templar Miko singlehandedly defeats the Order of the Stick to drag them in chains to Azure City. Later, after Miko kills Lord Shojo, Roy knocks her flat fairly easily, and mentions that this time, besides Miko having Fallen, Roy was using his Ancestral Weapon (which had been upgraded immensely) and not a stupid club. Also, Word of God says that the reason her clothing turned grey was because many of her magic items only worked for Paladins in good standing, which she was not at the time.
 * Durkon rationalises that the rain that prohibited the team from working effectively the first time they battled Miko was a divine sign that they weren't going to win this one. However, she did beat them a second time without the rain slowing the party down. Or he could've been trying to justify why he surrendered the first time and only healed the second time.
 * Roy's comment, "Stupid railroad plot," lampshades this nicely.
 * In Girl Genius, Franz Scortchmaw, the Great Dragon of Mechanicsburg ("…you may have seen him on the town's arms"), the First And Most Dread of Dragons, was mostly sleeping for the last few decades. He was more than capable of defeating inferior monsters and vehicles of the invading forces, but when he met another dragon, it quickly became a Curb Stomp Battle. When the other guy was about to finish him off, Agatha have remembered some things about Heterodyne designs, figured there's nothing to lose, and shot him with Gil's lightning stick. It turns out she guessed right, so after that it was a Curb Stomp Battle again, but this time with Franz beating up the invader.

Web Original

 * A version of this occurs in "Have Yourself a Monkey Little Christmas" in the Whateley Universe. Chaka is put in significant danger during a fight because she'd just had her hips broken and reset! This is also a Chekhov's Gun, as the need was stated around her first appearance!
 * Yet again, Fey's infamous fight against Mule is revealed to include a good bit of Flu. Fey fought her in an arena where she couldn't draw upon her powers. In fact, she was put in there specifically because the administration heard her say "But I can't do a fight in there! The Ley Lines are so tangled that I'll hardly be able to do anything!" Furthermore, her foe can absorb her magical abilities. What follows is a rather fun run-and-gun.
 * In the second-to-last episode of Red vs. Blue: Revelation, it's revealed that Tex is destined to always fail at the last moment, because This explains how, throughout the series, Tex always managed to get captured, killed, or knocked-out at a critical moment despite being the strongest character in the series.

Western Animation

 * Word of God has this as something that came into play during the formation of the Book One Avatar: The Last Airbender finale: Giving Zuko injuries from both his ship exploding, and some sort of cold-based sickness from his near drowning experience in icy water (not to mention powering up Katara with what is noted to be an especially water-bending-favoring full moon), made it much more likely for Zuko to initially struggle to victory against her (winning once the sun comes out), then losing his rematch under the light of the full moon. Furthermore, when the sun does rise, Zuko one-hit-KO's Katara. During the third round, it was night again, they were in a freakin' snow storm (plenty of water to bend) and Zuko was half-frozen to death. The next time Zuko and Katara had a real fight he more than holds his own against her.
 * Similarly, Zuko is similarly handicapped by being unable to use any of his Firebending in his fight-to-a-draw against Jet in season Two. Doing so would have exposed his identity, especially after an earlier incident in the season where he'd shown his firebending in a fight to defend a town and was then immediately thrown out of said town, causing him to hold back with Jet.
 * In The Venture Brothers, Dermot "claims" the only reason Dean beat him up in a Wimp Fight was because he was sick at the time. Did I mention throughout that entire episode Dermot "claimed" that his hands were registered as lethal weapons.
 * Kung Fu Panda: Legends of Awesomeness sees Temutai try to invoke this the second time he faces off with Po, claiming that the last time they fought, he had a head cold. It's very obviously an excuse he made up on the spot.
 * Happens in the second Season Finale My Little Pony: Friendship Is Magic when Queen Chrysalis manages to defeat Princess Celestia in a straight up fight. Chrysalis had gotten a major power up feeding off of Shining Armor's love for Princess Cadence. (As a note, that exact same power of love proved sufficient to curbstomp the entire Changeling army about ten minutes later, once Chrysalis lost her tap into it.) Not only does she visibly struggle against Celestia's power, even Chrysalis is outright shocked she won.
 * It's also noteworthy that Chrysalis' plan was not to fight Celestia head-to-head at all — the only reason she was doing so is because she'd gotten exposed as an impostor halfway through the wedding and was backed into a corner by an angry Princess who had been officiating at the ceremony.
 * Season 4's finale provides even more context on this and another explanation. Judging by the size of the craters left behind in the struggle between Alicorn Twilight and Tirek, if Celestia had unleashed her full offense during this episode she'd have killed everypony else in the room. She not only had to face an opponent temporarily juiced-up on almost-alicorn levels of power, she had to do it with one hoof behind her back and struggling to keep the collateral splash of the battle from harming the completely unprotected civilians standing less than twenty feet away. In light of all that, its amazing Celestia managed even the showing she did.
 * Season 4's finale provides even more context on this and another explanation. Judging by the size of the craters left behind in the struggle between Alicorn Twilight and Tirek, if Celestia had unleashed her full offense during this episode she'd have killed everypony else in the room. She not only had to face an opponent temporarily juiced-up on almost-alicorn levels of power, she had to do it with one hoof behind her back and struggling to keep the collateral splash of the battle from harming the completely unprotected civilians standing less than twenty feet away. In light of all that, its amazing Celestia managed even the showing she did.

Real Life

 * The suggestion is often made that the French lost the battle of Waterloo only because Napoleon was ill with piles (or some other complaint).
 * Maybe, although some people think the flanking manoeuvre by the Prussians played a big role as well.
 * There's a Voltaire short story called Lord Chesterfield's Ears that's based on this sort of idea.
 * The Battle of Borodino, the turning point toward a Russian repulsion of Napoleon's invasion, was lost (according to some historians) because "Napoleon had a cold." Leo Tolstoy says of this that that means "the adjutant who forgot to give Napoleon his waterproof boots [two days earlier] was the savior of Russia."
 * Used as an excuse so many times, especially when it's a massive upset or a loss that is much more lopsided than anticipated. It may or may not involve home court/field/ice advantage and it frequently involves injury and/or fatigue.
 * When [insert your favorite team in [insert sport here] here] loses a game.
 * The New Zealand Rugby team was suffering from food poisoning at the final of the 1995 World Cup, to the point where they can be seen throwing up on the sidelines.
 * A legend has Auburn University cadets greasing the rails before an opposing football team from Georgia Tech arrived, causing their train to slide past the station, and forcing the team to tire itself out walking back to the stadium.
 * Averted in Game 5 of the 1997 NBA Finals between the Chicago Bulls and Utah Jazz, to this day thought of as "The Flu Game". According to The Other Wiki, Michael Jordan woke up the day before the game nauseated and sweating profusely. He was diagnosed with food poisoning. He barely had the strength to get up out of bed, and the Bulls trainers told him there was no way he could play in Game 5. The Bulls would be at a distinct disadvantage without their leader, because the Jazz had just won two straight games to even the series, and whoever won Game 5 would be one win away from the championship. But he rose out of bed three hours before tip-off, determined to play. And after a listless first quarter in which the Jazz ran off to a 16-point lead, Michael led the team back to a 90-88 victory, finishing with 38 points, seven rebounds, five assists, three steals and a block. And then his teammate Scottie Pippen helped carry him off the court.
 * Nearly every losing sports team ever. It can't always be the referees' fault.
 * In college football, a famous recent example would Colt McCoy at his last Rose Bowl Game. The momentum of the entire game reversed suddenly - all because McCoy got tackled by a nearly 400-pound man early in the game, taking him out of the game. It wasn't even an especially brutul hit, but the physics somehow left his arm with no sensation whatsoever. He didn't feel any pain and his arm hadn't suffered serious injury, but he couldn't feel the football contacting his palm and fingers and thus couldn't make accurate throws. Truly a bizarre moment in sports as a QB had never before been knocked out of an entire Super Bowl or BCS Title game before, much less on such an unusual injury.
 * Two recent NBA examples: The Spurs in 2000 and the Celtics in 2009 were defending champions but late in the year lost their best player (Tim Duncan for the Spurs, Kevin Garnett for the Celtics) for the entire playoffs and suffered an early playoff exit to an otherwise inferior team.
 * Oddly enough, at least in the US, defeats are always blamed on this while victories are credited to divine intervention. The reverse is almost never the case.