Daisuke of Bitter Virgin delivers one to a would be rapist of Hinako, very nearly beating the man to death with a plank of wood and would have if Hinako hadn't stopped him.
In the final battle between Suzaku and Kallen's Knightmare frames in Season 2 of Code Geass, since they're both fairly evenly matched now, nor do they have to withdraw due to other circumstances as in earlier battles, fight pretty brutally. Both of their Knightmare's get heavily damaged, to the point where the only thing really left of their mechs afterward is an arm or leg (although Suzaku "loses" by having his blow up). It's an example of a mecha How Much More Can He Take.
Any time a character shows of their new training or powers such as: Goku's one shotting of Nappa, Vegeta's use of a fake moon to turn into an Ozaruu and literally crush the life out of Goku, Vegeta against Qui and later Dodoira, Zarbon's use of transformation, Vegeta demonstrating Sayan zenith to Zarbon, The Ginyu's vs. Vegeta Krillin and Gohan, Goku vs. the Ginyu's Frieza in each new form to someone else, Goku once he achieves Super Sayan... The rest of the series continues in much the same manner...
Frieza's legendary beatdown of Vegeta, right after Frieza achieved his fourth and final transformation. In the uncut version (read: the one you won't see on Cartoon Network), it's quite possibly one of the most savage beatings bestowed in all of anime. Frieza literally pummels Vegeta until Vegeta can barely move from the pain and injury, tears of humiliation and agony dripping from his eyes. And just when Goku arrives and it looks like it'll be a Big Damn Heroes moment, Frieza finishes the fight by blasting Vegeta through the heart, killing him. While most of the cast is quick to admit Vegeta can't keep his mouth shut, Goku is heavily enraged by Kick the Dog-methods of one-sided fights. In fact, apart from Super Saiyans, all of Freeza's fights reached a point where he'll get fed up, power up, and utterly destroy his opponent without even trying: Nail, Krillin, Gohan, Piccolo, Vegeta and even Goku were almost killed in direct confrontations this way.
Just as harsh: Hercule/Mr. Satan's daughter Videl is savagely beaten to the point of crying by her superpowered opponent, Spopovich in the Tenkaichi Budokai tournament. He takes this almost literally as the last move he used was standing on and attempting to crush her skull against the tournament floor. During the first half of the fight Videl gave him a pretty far going beatdown, as she didn't know the true extent of the power Gohan had trained her to, but was just trying to win. She and the audience even thought she accidentally killed him at one point, but it turned out for this guy having your neck suddenly wrenched around 75 degrees by a roundhouse was far less than fatal. Of course, considering he barely registers any damage later in the fight, it's likely he let her beat the crap outta him for shits and giggles.
Vegeta notes that had Spopovitch killed her, he'd have been disqualified, which would have messed up the plans of stealing energy from Gohan or Goku for Majin Buu. Though he was certainly enjoyinghis part of the fight.
Also, earlier in Dragon Ball, Piccolo Daimao, even taking his robe off for some Serious Business, handed one of these to the young Son Goku. Even momentarily stopping his heart beating.
Raditz's first fight with Goku, which ended with him stomping on Goku's chest.
Vegeta's fight with Kid Buu when Goku needed one minute to charge enough energy to defeat him.
Pretty much any fight with Buu in any of his forms. First he one shots Dabura, Gohan and then curb stomps the lord of lords, then when Vegeta stops him from eating the lord of lords he traps Vegeta in a piece of his own stomach and then beats him half to death. He also stomps on Gotenks until Goten and Trunks train in the hyper-bolic time chamber for 4 months and even then they can only just harm him and then go toe to toe by going Super Sayan 3. Once Gohan returns the situation the keeps reversing depending on which form Buu is in and who's fighting him
Any time he lets his anger loose, he will be handing one of these to somebody. Unfortunately, he usually can't maintain his pissed-off state long enough (most people in DBZ would require a week-long beatdown to actually lose a fight). But man oh man, as long as he stays mad he will ruin your day.
Gohan going SS2 had him deliver one to Cell, only using a Ki attack at one point in the fight and mostly pummelling him. Turning SS2 gave Gohan a sadistic streak rivaling Frieza and had him let Cell hit him once just to show how outmatched Cell was, and as the fight went on it became clear Gohan was just dragging the fight out to torture him, which eventually backfired.
And, at the late Buu saga, he doesn't need to be mad to have access to his full power. And demolish Buu with mere punches and kicks.
When he first encounters the androids, he beats 17 down to the point where he can no longer even move, only able to watch in horror as Cell prepares to absorb him.
To say nothing of Cell's utter decimation of Piccolo immediately prior.
He defeated Hercule by just slapping him.
Common in the movies, with Goku getting one from Turles after the latter ate of the fruit from The Tree Of Might, which had a notably brutal Kick the Dog moment when Goku could barely stand and Turles pummelled him with repeated Ki blasts. More famously, any fight involving Broly has him do this before his beaten by a Deus ex Machina.
Johnathan Joestar's beatdown of Dio Brando in the first part, wherein he beats Dio so badly that Dio actually starts to cry. Considering how much crap Dio had put Johnathan through from literally the moment the two met, this was really cathartic.
Most main characters get at least one of these throughout the course of their part of the series, though not usually against the main villain. Jotaro completely annihilating Steely Dan after being put through all kinds of torture while he held his grandfather hostage comes to mind. The guy gets beaten up for three full pages, mind you (and over twenty seconds in the anime).
Which is topped by Giorno giving the biggest beatdowns in the manga to Cioccolatta for about 7 pages straight, ending it by punching him into a garbage truck.
On the villain side, there is Vanilla Ice subjecting Iggy to one in rage for being forced to destroy an effigy of his master Dio. Iggy is actually killed as a result of the beatdown
In Yu-Gi-Oh!, the end of the battle between Yami and Insector/Weevil on the top of the train qualifies as a hero-on-villain version of this trope. Despite already having won by the game rules, Yami just keeps on pulling his kill spell effect on a defenseless Weevil.
And he would have probably continued until Weevil fell unconscious from the pain had Anzu not intervened
At the beginning, Nagi Souichirou picks a fight with Takayanagi Masataka, biting off far more than he can chew when Masataka blocks his cheap shot with a chopstick, then proceeds to Kamehameha the punk across the room. Masataka decides to play the role of villain for a bit and swiftly proceeds to rearrange Souichirou's face with an unending flurry of kicks. Masataka eventually falls victim to another cheapshot from Souichirou, which, most unfortunately for our main protagonist, prompts Masataka to descend into a berserker rage, massacring Souichirou in one of the most brutal beatdowns in the series. The "fight" ends with Masataka intentionally missing his final wall-shattering punch (floor-shattering in the manga) as Souichirou passes out. Watch it here.
Also in Tenjho, when Aya faces off against Shiro (the staff guy) during the bowling alley fight. After Shiro inadvertently awakens her Dragon Eyes, Aya proceeds to beat the poor guy within an inch of his life, with his own weapon, laughing all the while. (Granted, she did feel pretty bad afterwards.)
Roy Mustang confronts Envy and learns that Envy killed Hughes. Cue the Curb-Stomp Battle, with Mustang repeatedly mutilating and incinerating Envy in the worst way imaginable, Ed and Hawkeye are barely able to talk Roy down from literally crushing Envy's True Form like a worm under his boot… Whereupon Ed instead Talks The Monster To Death.
And of course there is King Bradley Vs Greed. Lets just say that Greed died at least 16 TIMES without even coming close to being in the position to retaliate.
Bradley: So Greed old boy.....How many times would you like to die?"
During the final battle, just after Al sacrifices his soul to get Ed's arm restored, Ed proceeds to brutally beat the remaining Philosopher's Stones out of Truth!Father one punch at a time with his bare hands.
In episode 22 of the 2003 anime adaptation, Envy totally humiliates Edward and Lust and Gluttony take Alphonse hostage. The only reason the Elrics got out of that one was because they were saved by Scar, who actually did much the same thing to Ed in an earlier episode. And then of course, there's the final battle with the homunculi, in which Envy sadistically kills Edward after revealing that he is actually Edward's half-brother..
In Digimon Tamers, Guilmon, Renamon, and Impmon all end up on the receiving end of one. Of particular note is Impmon's, which was horribly brutal and can be summed up as a two-foot-tall cat-thing getting thrown through buildings and stomped on by a bipedal horse three stories high. The "fight" was so uneven that Guilmon and Terriermon were paralyzed by horror, Takato and Henry looked like they were going to be sick just watching it, Rika actually begged Renamon to help him, and eventually Renamon decided to jump in, albeit at the last second to respect Impmon's wishes.
Thorkell, a Blood Knight extraordinaire and major antagonist for part way through continually lays a beat down on the protagonist every time they meet in combat, often with his bare hands, though he loses an eye and a pair of fingers at the same time.
Askeladd's no stranger to this as well, as the latest 'duel' between him and Thorfinn was arguably the most humiliating bare-handed asskicking the latter's gotten to date in the series. In this case, however, it was mostly Thorfinn's fault, having challenged Askeladd while he still had a broken arm, and having failed to learn anything about finding new moves and keeping a cool head from their previous duels.
The first proper fight between Saito and Kenshin eventually turns into this after Kenshin is stabbed, and when Saito ends up using his belt and coat to try and strangle Kenshin after losing his sword he then resorts to his fists. A wuss, Saito is not, and Kenshin's forced to awaken his Superpowered Evil Side just to survive while Kaoru watches helplessly. Luckily, they're stopped Just in Time before they actually manage to kill each other. Later, the fight with Enishi goes a lot like this, but once again they're stopped by Kaoru.
Saito hands out another beatdown later in the series, this time to Sanosuke, to prove that he couldn't hack it in the coming battle in Kyoto. For the extra kick in the teeth, he trashes him at unarmed combat. Further more, he does it while avoiding Sano's shoulder injury, a weakness he would normally take advantage of.
This trope is inverted during the first Kenshin/Enishi fight. After Enishi says he's to kill Kaoru, Kenshin goes into an Unstoppable Rage and beats the crap out him, putting away all the fancy techniques that Enishi easily defeated earlier.
A rule of thumb is that this will happen to some degree whenever Luffy deals with a Logia Devil Fruit user, or one of the Shichibukai. The most obvious examples are Crocodile (who delivers it in a classic style after revealing that Luffy can't hurt him at all), and Aokiji (who does it, all at once, to the best of the heroes, taking The Worf Effect to its logical extreme).
Magellan managed to invoke this (despite being a Paramecia) in every fight he took place in during the Impel Down arc. Luffy's strength meant nothing when Magellan only had to touch him once with his poison for a fatality, and he was unable to land a hit in turn without covering his hands in the poison. It was possibly the closest Luffy has come to dying to date.
Hannyabal, his direct assistant suffers a truly sad, yet awesome beat down from Luffy, as he is obviously outmatched; yet is constantly is willing himself to get back up, especially after being hit by the same attack that knocked Lucci, yes that Lucci out cold, because of his unwavering belief of protecting the people of the world from criminals.
Subverted when Luffy faces a Logia Devil Fruit user he actually has an advantage over, and proceeds to kick his ass. When God Eneru recovered, he was too terrified of Luffy and didn't actually want to fight him anymore. His solution was to trick him by grafting a giant golden orb on Luffy's arm. When Luffy returned he gave one final move that completely defeated Eneru.
He also delivered a spectacular one to Hody Jones, who, despite his exceptional Determinator abilities, was still doomed to continually get his ass beat. For that matter, Caesar Clown also received one the second time around; while he may have won through simple Combat Pragmatism the first time around, there's not much that you can do when faced with an enraged Luffy. Also, they both really had it coming.
In an odd neutral-on-hero example, when Zoro challenges Mihawk, supposedly the world's best swordsman, to a battle, Mihawk proceeds to effortlessly block everything Zoro does with a tiny dagger. He proceeds to stab Zoro in the chest and, when Zoro refuses to surrender, he agrees to use his BFS, with which he shatters two of Zoro's swords and almost kills him. He only lets him live because he wants to see if Zoro really can surpass him.
A rare hero version occurs when Chopper activates Monster Chopper. The previously one-sided fight with Kumadori suddenly becomes a smackdown so brutal, you actually feel sorry for the villain who had previously just beat the hero within an inch of his life.
Bellamy beat up Montblanc Cricket and the Monkey Brothers, Luffy heads back to Mock Town and hands him a extremely satisfyingone-hit KO.
Marine Admiral Akainu for most of the Marineford arc was the living embodiment of this trope. Most notably his brief one encounter with Ace
Ichigo is delivered a No-Holds-Barred Beatdown by Grimmjow and Tesla (though in the latter case, he was half dead after defeating the former anyway.
And before that Yammy gives him, one after his Heroic BSOD kicked in.
Then later on, Aizen delivers one to Gin. Admittedly Gin had just stabbed him, but after Aizen came back again, he proceeded to slash him across the chest, rip his arm off, stab him through the chest, and finally throw him through a building.
Ayon cements himselfitself as the only thing in the Manga almost as terrifying as Barragan by delivering several almost impossibly brutal versions of the One-Hit KO. It tears out half of Rangiku's torso before she can blink. It crushes Momo's ribcage with a single punch. It attempts to crush and eat Hisagi when he attempts to take it on, and blows Iba away with a backwards glance during his attempt at Big Damn Heroes.
Yamamato delivers one to a special hollow that was created to stop his Infinity+1 Sword. The hollow rendered his sword useless, but Yammato simply killed it with a set bare-handed attacks.
Ulquiorra slowly escalated this during his final fight with Ichigo; before he kills him after advancing to his second release, Ulquiorra's pretty much beating Ichigo into the roof of Las Noches with all his might.
As Nodt delivers the most brutal one of the story when he does it to Byakuya. He steals Byakuya's bankai, paralyses him with his 'Fear' power and then uses the stolen bankai to rip Byakuya's body to shreds, leaving his half-flayed body glued to a wall with his own blood. This is particularly notable because Byakuya's bankai has always been capable of doing this to every opponent it fights against, but Byakuya has never used it so viciously.
Anytime Ichigo's Hollow surfaces, such as the fight with Byakuya, later Grimjow and then finally against Ulquiorra. In each of these examples Ichigo was being given a no holds beat down until he was on the verge of death or in one case actually dead at which point his hollow took charge and started to even things out.
Ninja Scroll: Himuro Gemma delivers a beating of this type to Jubei. Not even getting his arm cut off stops him. Getting his skull bashed in does, temporarily.
Another beatdown occurs earlier in the series during the Tournament Arc. Yusuke and his opponent realize that they're running out of strength, so they decide to keep trading blows between one another until one of them finally collapses. Yusuke comes out winning, being the Determinator he is at times.
Then there was Bakken, who both gave and received one. First, he decided to play around with Kurama, who had just survived two brutal fights in a row and was essentially asleep on his feet. Since Kurama was still standing in the ring, his opponent claimed this meant he was volunteering to fight. Bakken slammed Kurama's body around like a rag doll for several minutes before they finally called the match over. He was only convinced to stop the carnage by the threat of Yusuke shooting him in the back: rules or no rules. Whereupon Yusuke himself takes up the fight... and despite Bakken's mist ability promptly dealt him back for every blow given to Kurama earlier: only with Yusuke's much-stronger fists. Adding insult to Bakken is the fact that Yusuke also took every blow he threw at him and shrugged it off before beating him to a pulp when he was begging for mercy.
Younger Toguro's fight with Yusuke in the final match was very evenly matched...until he goes 100%. it took a supposedly Heroic Sacrifice from Kuwabara to make the hero be a real threat to the demon because it was WAY TOO ONE SIDED, to the point that Yusuke was being beat around like a rag doll.
And then there is Genkai Vs The Beautiful Suzuka. Genkai pounds him so hard indents of her fist are left all over his body, and his face has been bruised and to the point it's unrecognizable. Made particularly funny in that she viciously beats him senseless while shouting loudly about how his vanity and weakness keep him from becoming a real fighter...only to instantly stop with a quiet "that's enough" once he's thoroughly pounded.
Kuwabara receives two of these during the Dark Tournament arc. The first is during a three vs. three fight and the good guys have just learned that their opponents are Brainwashed and Crazy. Kuwabara, subscribing to the Honor Before Reason school of thought, refuses to attack them any more and the three gang up on him. It ends about as poorly as you'd expect. The second example is in his very next fight, before he's had a chance to recover. Due to several counts of trickery, Hiei and the Masked Fighter were disqualified before the match could begin, leaving Kurama and Yusuke as the only fighters with most of their bones intact to face five opponents in a row. Fatigue claims Kurama halfway through the third guy, and Yusuke is disqualified on a technicality before his match with the final one. Kuwabara is yelling in pain while climbing into the ring, but he agrees to fight for his team because he's the only one left. As it turns out, his opponent's power involves covering himself in rock and slamming himself into an enemy. Kuwabara's already broken body takes several of these attacks before Yukina shows up and The Power of Lovegives him a second wind and renews his energyso that he can send the guy flying with one shot.
Even more recently, Hinata takes on Pain to protect a helpless Naruto, finally confessing her love for Naruto before charging the most powerful Ninja in the world without a trace of fear. Pain proceeds to sidestep her attack, crush her into the ground with gravity, and seemingly stab her to death in front of Naruto.
While the manga version of the above doesn't count, being a One-Hit Kill, the anime version plays it brutally straight as Hinata repeatedly takes brutal blows from Pain's Shinra Tensei that leave her eventually unable to stand, yet she doesn't give up even when she's reduced to crawling on her hands and knees!
After seeing Hinata get stabbed, Naruto inverts this beyond anything ever seen in the anime. Naruto, suffering from the loss of his master, his village and his first teacher, loses all hope and resorts to the Nine-tails to bring down Pain. In the anime, Kyuubi Naruto, already in the 4-tailed state, mercilessly beats him on the Megaton-scale, yet Pain is unscathed. Angered even further, he transforms into a never-before-seen 6-tailed form and attacks him with far more power than before. Ironically, he doesn't attack Pain in his 8-tailed state, considering he was trying to break out of a moonlike mass that Pain trapped him in.
Really most of the arc was Pain doing this to all of Konoha. Naruto was the only one who can really do any significant damage to him in a non-Pyrrhic way (Kakashi, Choji, and Choza vs. Deva path is the only one that could even be considered a "battle"), and he only arrives halfway through. And still got his ass kicked in the end. And the only reason he lasted as long as he did was because Pain was holding back because he was trying to capture, not kill Naruto.
Chapter 605 has Obito completely dominating the Hidden Mist ninja after watching Rin die. They could not touch him, literally and figuratively.
In chapter 608, there is Obito doing this to Kakashi. First Kakashi takes a giant shuriken to the knee, then he's sent to another dimension, he comes back, is kneed in the chin, stabbed in the shoulder, punched, and finally takes a double cross-swipe of shuriken to the chest. All of this in a single chapter. And guess what? He's still standing!
Lordgenome, in Tengen Toppa Gurren Lagann. Unique in the fact that he delivers one, bare handed, to a mecha. Not just that, he climbed out of his own mecha as it was in the middle of being destroyed by the hero and messes him up barehanded. And because obviously this wasn't spectacular enough, the second movie takes this trope to Up to Eleven during the Final Battle, during which the Anti-Spiral King finally snaps and proceeds to beat the living hell out of our heroes while furiously ranting about the sacrifices made by his race and how the good guys are nothing but a group of reckless fools whose actions will doom the universe, culminating in the brutal dismemberment of The Show's Namesake Mecha.Seriously, the squiggly man was pissed. After which they get back up and give him a beatdown in return.
Played with in Kinnikuman when Brocken Jr. faced off with Ramenman. Brocken delivered one of these to Ramenman for a time until deciding to use the Camel Clutch, the move Ramenman had killed his father Brockenman with. At that moment, Ramenman asks if Brocken is all out of moves and proceeds to break free and beat Brocken down.
Played straight in the chapter "Crazed Robin Mask": Robin Mask, humiliated and bleeding after a lucky shot from Kinnikuman, promptly goes berserk and pummels his opponent into the ground.
In Fushigi Yuugi, Tasuki receives one of these from Brainwashed and Crazy Tamahome. They're more or less evenly matched when the fight begins, but Miaka can't bear the idea that her beloved Tamahome might be hurt or killed, and begs Tasuki not to use his weapon. He obeys, challenging Tamahome to be a man and fight him bare-handed instead. Tamahome promptly responds by hitting him in the face with his weapon... which knocks Tasuki down, where Tamahome proceeds to grind his face into the ground and issue one of the most prolonged, violent beatings in the series. Eventually, even Nakago arrives to pile on.
Possibly one of the greatest examples in all of anime occurs in Karas: The Revelation. The hero Otoha has been stripped of his powers, but it's revealed that, possibly due to a genetic disease ( he's incredibly bishonen for being the product of incest)), he's incapable of feeling pain. He readily cuts open his own hand with his sword without so much as wincing, and he more than once takes bullet wounds in fights and carries on with barely a hesitation. Even with this knowledge however, the audience cringes during his fight with a bull demon in a subway station: without his powers as Karas, Otoha is massively outclassed, and although he briefly holds his own, he's eventually impaled on a spike the width of a car tire and hurled the length of a city block... and he still gets back up. To elaborate. He survives a Wave Motion Gun attack. There's a moment where it really looks like he's going to summon up some supernatural power, one brief moment of hope, but it doesn't last. His Karas sword SHATTERS, he's got shards of glass or metal in HIS EYES, minus one arm. And he still TRIES to keep fighting. Which basically results in him collapsing forward, lamenting his weakness. And then, he became a Karas again, and delivered a curbstomp of his own to what was, in all likelihood, the weakest monster of the series.
"Karas: The Prophecy", being part 1 of the previous entry, opens with quite possibly the most epic battle of the entire series. Between Eko, the former Karas, and his replacement. Eko, being hundreds of years old and only recently replaced, delivers a fairly one-sided beating to the Karas who preceded Otoha. With Crowning Music of Awesome in the background. And transformations from samurai / ninja to something resembling fighter jet combat. Basically, whenever Eko enters the fray, a beatdown is about to commence. To the degree where its DISAPPOINTING that he Scaled Up into a giant asian-style mecha-dragon looking thing. As giant monstrosities never seem to put up as good a fight as a human Big Bad, and do not lend themselves to epic kung fu battle. Which was what made Eko such a wonderful villain. He knows that Authority Equals Asskicking and he's not afraid to do it. Which makes sense, considering he spent centuries as a monster-fighter in Japan...
One episode of Darker Than Black has the protagonist undercover as a waiter in a Yakuza run restaurant. He is attacked by a disgruntled patron who in the process causes a lot of damage to the restaurant. The next scene shows the protagonist befriending a young gangster while the customer is being savagely beaten in the background. Much more to the point is the fact that the first time we see Our Hero, he does this to someone. The guy was pretty much helpless, since he had the incredibly sucky remuneration of breaking his own fingers. Hei beat the everloving crap out of him, including knifing and kicking his freshly-injured hand to get him to talk. He finished by zapping the guy to death. Why yes, Hei is an Anti-Hero. Why do you ask?
The second episode of Kino's Journey features a Neutral-on-Villain version of this as Kino is told to drop her weapons in a pile... and then quickly annihilates the three slavers with one of her remaining weapons. As The Stoic, she doesn't show the typical rage these fights often develop, but it's messy, violent, and very, very brutal.
Shion (disguised as Mion) delivers one of these to Satoko, she ruthlessly beats the little girl in the middle of the class room while berating her for crying and taking up all her brother's time. She was about to kill her, saying that a cracked skull would shut her up, when Rika threw herself in front of Satoko saying she would also have to Go Through Me and Rena joined her. Shion was about to also take them out, and then she was Punched Across the Room by Satoshi... the boy she was doing it for. It should be noted that while this event was only shown in one chapter, since it is part of the back story (taking place a year before the main story) it is assumed to happen in every world.
In the third episode of the OVA, Satoko gets another beatdown, this time from Rika armed with a chair. First with a chair thrown hard to the face followed by four or five solid blows delivered at full force stopped only by Rika's mercy. However in this instance, Satoko was practically asking for it.
In the sound novel Rika hits her with the chair, then hits her. It's not as violent or traumatizing as the anime, but still effective.
Mahou Sensei Negima! has Heroic Resolve turn every fight Negi participates in into one of these at some point, since its a theme of his character to have such difficulties due to inexperience. Interestingly, the most intense of these came at the hands of another good guy during the end of the tournament arc. Negi got back up, and pulled out his new upgrade...and still can't win.
In Deadman Wonderland, this happens to Ganta during the majority of his battles. The only thing that keeps saving him is that, in the end, when everything looks hopeless and he's about to give up, he always gets a surge of energy and determination that makes him stand up again.
In Rave Master Haru does one of these on Lucia using a demon sword, and even almost kills him before Elie snaps him back into his senses. Then Lucia pulls one of these on Haru and almost kills him before Shuda intervenes and gets killed instead except he recovers. The fight this sparks is significantly less one sided.
And not forgetting(as much as would like to) Transformers Energon, wherein Megatron revives as Galvatron and proceeds to brutally kick the scrap out of Scorponok, brand him with the Decepticon sigil, then use his body as a shield before proceeding to rampage out and thrash our brash young hero-Bot (off-screen, but still). Then there's his Mind Rape of Starscream...
Episodes 2, 18 and 19 each. In short: if Unit-01 goes berserk on you, you will die. Horribly and messily.
End of Evangelion has a rare two-way No-Holds-Barred Beatdown, with both sides delivering it to one another. Asuka absolutely wipes the floor with the entire JSSDF army, beginning by lobbing a battleship into the heavy artillery and then literally stomping the gunships. Even the MP Evas don't slow her down; she destroys all of them in less than the 3 mins of power she has left. And then it gets turned around in a horrifying anddisgusting way. Turns out the MP Evas are effectively immortal. So they regen when she has run out of power, shove a spear through her eye, and then eat her alive. Then lob about 6 more spears, one of which splits HER ARM in half into her body. Even those people who hate Asuka would probably wince and agree that was the worst death of the series.
Rebuild 2.22 has this in an awesome way, that wouldn't fit in Neon Genesis Evangelion, but fits surprisingly well here. In short, Badass Shinji curb-stomps Zeruel using Angel-like abilities. To elaborate a bit, Zeruel first beats up EVA-02 in its The Beast Mode, where it's a lot stronger, because its limiters are released. Then EVA-00 comes with an N2 Mine and suicides against Zeruel, only to be burnt to a crisp while Zeruel is unharmed. Zeruel then proceeds to eat EVA-00 in one bite, leaving only its feet. Shinji then shows up in EVA-01 just when Zeruel is only a few minutes from fusing with Lilith, saving everyone at NERV HQ, and launches himself and Zeruel up using one of the high-speed elevators. Zeruel then rips the left arm of EVA-01, and throws it away, after which the EVA's internal power source runs dry... Only to suddenly be fueled by Shinji's Badass! He even creates a new left arm out of nothing but his AT-Field, and uses what can only be described as a Rocket Punch, after which his EVA sprouts wings and initiates Third Impact, just because Shinji wanted to save Ayanami. All while "Tsubasa wo Kudasai" is playing in the background. Yes, a Japanese children's song is playing while Shinji accidentally initiates Third Impact. And somehow, it all fits perfectly within the scene...
In the Suruga Monkey arc, features Suruga with her Rainy Devil beating the living crap out of Koyomi, breaking his wrist, taking some teeth out, and other unpleasant things. The top of the cake? She rips his abdomen open, takes his intestines out and slings him around the room by his intestines until they rip, sending him to a violent crash against the wall. And she's not finished (Koyomi would have suffered a horrible death if it weren't for Senjougahara, who appears in the midst of it and saves the situation).
And again in Nisemonogatari he gets his ass kicked again by Yodzuru, which includes him being kicked though ceiling and later smashed into the ground.
That's the least of it, at one point she shoves her hand into his chest and crushes his heart. It explodes like a balloon.
There's also the episode "Electric Shock Showdown", where Pikachu got badly beaten by Lt. Surge's Raichu. It got even in the rematch after using Raichu's size against it. In DPP it battled a Raichu and almost died. It even Hyper-Beamed it in the face.
Then there's the episode "Tie One On" that has a rare mutual one of these, when Ash's Bulbasaur and another trainer's Meganium beat the crap out of one another, with the fight eventually breaking down into a Vine Whip slug-off that ends with both Pokémon collapsing after a double Solar Beam. It actually was personal, due to a fight earlier in the episode, but the fight between them both apparently makes up for it, as before Bulbasaur and Meganium collapse, they smile at each other.
In "'Primeape Goes Bananas", Charmander is the victim of one of these until it learns Rage, and even then it still takes quite a few punches.
"Odd Pokémon Out": Ash's newly evolved Sceptile is on the receiving end of one from Seviper and Cacnea. He couldn't even fight back because he lost the will to use any of his attacks.
Pikachu vs. Entei in Pokemon 3. For one thing, he's a Legendary; and another, Entei's a lot stronger than an ordinary Entei (which is already saying something). You can actually see Pikachu beat up and bruised (but refusing to accept defeat) in mere seconds.
In "A Poached Ego", Jessie, James and Meowth take on a Tyranitar with their bare hands (or claws in Meowth's case) in an attempt to buy Arbok, Weezing and their protectees time to escape. They lose very badly but still refuse to give up.
Mitsumi from Pokémon: Diamond and Pearl Adventure gives one to Hareta and his Pokemon after being forced by Cyrus to fight him to save her Eevee. Even though Hareta is a notoriously good fighter he still gets his butt handed to him and beaten up pretty good (both him and his Pokemon this time); the only thing really stopping Mitsumi is her soft side.
One Monster Rancher episode had Mocchi get the ever-loving CRAP beaten out of him by an opponent during a Tournament Arc. He wins, but collapses as soon as he's declared the winner. The beating itself was actually cut from the American version, for obvious reasons.
A minor example in Chrono Crusade: After Chrono had already been previously torn up in a fight (enough that he's missing an eye and an arm), Joshua finds out that his sister made a Deal with the Devil that will lead to her dying at a young age. His reaction is to start beating Chrono with tears streaming down his face, screaming that Chrono is a monster. Chrono doesn't even attempt to fight back, because he agreescompletely. Joshua stops short of causing any serious damage, so the scene serves to be less of an example of a vicious villain and more an example of two characters having two very different and very extreme reactions to grief. Cue sobbing.
Villain on scumbag example in Speed Grapher. Suitengu has a Pet the Dog moment where he accepts a girl's play money to pay off part of her father's debt to him (from attending a shady club). The father thinks that Suitengu generally accepts the play money as legal tender, and tries to sell a load of it to him. When Suitengu tells him that the circumstances were different before, the father takes it that Suitengu is a pedophile and offers to sell his daughter to him. Since Suitengu's earlier mercy was because the daughter reminded him of his dead sister, he savagely beats up the guy and then kills him, revealing his true intentions with each blow.
Applied by the thug in chapter 2 of Souten Kouro, to Cao Cao. Who is ten. Cao Cao does get even, though.
Seen in Cardcaptor Sakura, of all things, during the 'Final Judgment'. Sakura is pitted against Yue, who is actually Yukito, the one she loves. Yue starts things off by backhanding Sakura a dozen yards or so, and spends a good three minutes beating her into the ground, before crushing her in her own card, and telling her as she loses consciousness that her price for failure is the entire cast will lose their feelings for the ones they love. Although not as violent as other examples on this page, it's still tough listening to Sakura yelp as Yue slams her into the ground over and over.
Toriko has a weird example, in that it's a land's NATURAL FEATURES doing this when Toriko attempts to enter the Gourmet World. He is subsequently mauled by everything from the wind, to the gravity and even the droplets.
Samurai 7 has the show's Big Bad mark his descent into a Villainous Breakdown by shooting up mecha-samurai Kikuchiyo. When he runs out of ammo, he then proceeds to viciously beat him with the butt of the gun while screaming about how he hates everyone and everything and how he's going to crush everything under his heel.
Yaiba's battle against Soshi Okita during the last arc is this: the latter is unbelievably powerful, so skilled that can utterly destroy Yaiba just by counterattacking, and when he eventually attack his swordstabs are too fast to being seen. And despite unleashing his best attack on the Kid Samurai, the latter keeps coming. That battle was so one-sided and brutal that Soshi even beg Yaiba to stop fighting back, since he didn't want to kill him.
In one of the Detective Conan movies, both Ran and Conan get brutally beaten up by Irish from the Black Organization.
This is used in Puella Magi Madoka Magica to show just how badly Sayaka is being broken. She attacks a witch while laughing manically, blood streaming down her face.
In Dai Mahou Touge Punie-chan does this to Elise von Barbaroque after she fails to assassinate her.
In GaoGaiGar FINAL, Gai delivers one of these to Palparepa. And it is both brutal and awesome.
The last episode of the original GaoGaiGar features a pretty brutal one as well. Not surprising, though, as Palparepa's defeat reuses a lot of scenes from Zonuda's defeat.
Jake Martinez delivers one of these to Kotetsu in Tiger & Bunny once Kotetsu (accidentally) manages to hit him. Even ratings-chasing director Agnes is appalled and stops the live broadcast. Off-screen Jake also did similar to Sky Kigh, Rock Bison and - presumably, given how badly he was injured when found - Origami Cyclone.
And finally, in episode 25, Nanoha delievers one to Quattro.
Satellizer from Freezing dishes these out and receives them from her many fights in this series. Due to their super Healing Factor, and quite a bit of blood gets spilled, limbs get severed, and bones get broken quite often from these fights.
In AKIRA Tetsuo delivers one of these to a Clown gangmember for a) beating up him and Kaori, and b) trying to burn Kaneda's bike. Though comparatively short, it's quite brutal; when Kaneda actually tries to intervene, the once-shy Tetsuo actually snarls that he wants to see the gangmember's head split open. And this is before he develops psychic powers.
An unusual circumstance in Hunter × Hunter: In the Heavens Arena, where people fight for sport, one of Killua's opponents was Zetsu, a little boy with beginner-level hand-to-hand combat and little else. What Killua thought would be a Curb-Stomp Battle went on far longer than it should have, because no matter how many times Killua punched Zetsu and knocked him down, Zetsu kept getting up. This kept going until Zetsu's martial arts master, who was sitting nearby watching, had to yell at him to stop. (Killua had already pulled off a TKO early on, and by this point, Killua was feeling guilty about beating up a little boy.) It turns out that Zetsu had been using his nen, or life force, as a barrier against the punch and to cushion himself when knocked down, but didn't know how to do much else.
Mobile Suit Gundam: Char's Counterattack does this twice. The first time, Char and Amuro spot each other in Sweetwater Colony and Amuro tackles Char and the two start brawling. It isn't until Gyunei Guss arrives in the Hobby Hizack that Char's able to escape. The second time, the two men meet when Axis is falling. Once they're out of weapons, the gloves come off and they start slugging each other silly, to the point where Amuro's winning strike ends up launching the suit's ejection pod!
His father and grandfather get them, too. Flit gives one to Desil after he kills Yurin, and Asem gives one to Desil (again), after he kills mentor Woolf. Both also count as Curb-Stomp Battle - especially the latter, as in the span of roughly a minute and a half, Asem systematically severs every one of Desil's mech's limbs, then slices it in half, and then SHOOTS THE TWO HALVES. A generation later, Asem does the same thing with Zeheart despite a two-generation tech advantage in the latter's favor and the fact that in most every previous engagement between the two, Zeheart won. The actual fight in that case lasted under a minute, and about half of that time was devoted to dialog. Extra props to Asem in particular because unlike Flit or Kio, he is a Badass Normal, and his opponents in both cases had psychic powers.
Gundam Build Fighters featured a handful of pretty awesome fights too, where both toys got badly damaged. In episode 15, we have Sei and Reiji fighting Ricardo Fellini, and the result is that both Gunpla are left more devastated than seen before in that show. Later, in episode 24, we have Sei and Reiji against a mind-controlled Meijin Kawaguchi, who controls a very modified Exia, the Amazing Exia Dark Matter. Four shots from Exia's rifle is enough to charge the Star Build Strike's RG-System, though it doesn't stop Exia from making a mess of SBS. And that's before activating Trans-AM...
In Gamaran one-sided battles are usually extremely quick, but there are at least two examples of "beatdown":
Zenmaru Ichinose vs Sasuke Sasakibara: After getting nearly beheaded by the latter, Zenmaru decides to show up what his BFS can do: in the following battle Sasuke is costantly pushed back, gets slashed across the chest and face, lose a whole ear and the chunck of meat around it and his best attack is bitchslapped away before the conclusion.
Jinsuke Kurogane vs Kouma Todo: for his trouble and in spite of his best, nearly-impossible to dodge secret technique, Kouma is cut across the torso, his left arm is severed and is sliced six times in a row across the chest, turning his upper body in a pile of flesh, organs and bones.
Flame of Recca: Has this with Recca vs Kukai, while the manga is a shortened version of this, the anime however takes this Up to Eleven. For a short while, Recca is pummeling Kukai till he releases his Super-Powered Evil Side, resulting in the absolutely one-sided battle in the series till Recca somehow manages to bring forth the third dragon in the fight.
Eren's second fight with Annie in Attack on Titan devolves into one of these after Annie dismembers Eren's arm and leg. Eren then becomes so beside himself with rage that he gives the appearance of being on fire while attempting to tear her limb from limb. As she's running, it's the first time we see Annie visibly panic.
Earlier, to convince a tribunal that he can control Eren and his titan form, Captain Levi brutally kicks the shit out of the manacled Eren. It's non-fatal, and it doesn't inflict permanent damage (possibly due to Eren's healing factor), but it continues for a long time, and is vicious enough to shock everyone watching it out of their various states of panic, and get Levi's proposition their full attention.
For more context behind that: in her first battle against Elite Four member Uzu Sanageyama, Ryuko wins by blinding him, crippling his sight-based Hyper Awareness. For their rematch, Uzu has his eyes sewn shut, which allows him to gain a new form of Hyper Awareness that cannot be negated. He proceeds to completely pound Ryuko into the ground while calling out the above words with each strike, and only his uniform overheating and shutting down saves her from death.
Later on, when it's revealed that Satsuki was actually rebelling against Ragyo the entire time, the later eventaully breaks free from the impalement that the former put her through, and breaks Satsuki's sword WITH HER BARE HANDS, then starts to beat her own daughter to a pulp.