Played gruesomely straight in Unit-01's utter massacre of Unit-03, both in the original show and Rebuild.
Kallen gives Suzaku one of these not just once, but twice, in Code Geass, for nearly injecting her with Refrain; the second time being in Knightmare Frame combat where she almost kills him, only to be deferred when he accidentally fires off FLEIJA.
Seras Victoria's fight with Zorin Blitz in Hellsing following Pip Bernadotte's death. Seras is so angry that by the time she's done, most of her enemy's head is a red smear on a brick wall.
Ai no Kusabi's Iason Mink during a brief brawl, tears off Guy's left arm after he finds out what Guy did to his beloved Pet. He later says it was justified retribution.
Averted in Fullmetal Alchemist. When Ed realizes what Shou Tucker did to his daughter and dog by transmuting them into a chimera, he pins Tucker to a wall and starts punching him in the face. Tucker does not help the situation with his Not So Different speech.
One of the traits of Seiten Taisei Son Goku in Saiyuki is that he now fails to be able to see what is going to far. In one scene that would have been narm if it hadn't been so brutal, Goku sits on Kougaiji (who incidentally is refusing to bring Sanzo to a village to get the antidote for what he's been poisoned with) and proceeds to cheerfully and without reserve, begin punching him until his bones are pretty much liquid. The worst bit is that Goku considers Kougaiji a kind of friend, and generally considers fighting with him as a sort of game... Seiten Taisei apparently does too, he just doesn't know when it's not fun anymore...
Issei: President Rias Gremory's virginity belongs to me!!!
Eureka Seven has Renton whale on an already disabled LFO with fists of Nirvash (despite actually having melee and ranged weapons) until his entire mech is drenched with red fluid. Even the person he was rescuing, a hardened soldier, is stunned by the sheer brutality of it. The thing that finally snaps him out of it is seeing a dismembered arm of the pilot with a wedding band and realizing he just beat a real person into an unrecognizable bloody pulp. Cue the Vomit Discretion Shot.
In Holyland chapter 129, some seniors pushed Masaki's Berserk Button to lure him into a trap. In chapter 131, he paid two of them back.
Attack on Titan has this in the backstory of Eren and Mikasa, when the former rescued the latter from kidnappers. Using the idea that Children Are Innocent to fool the men into letting him into the cabin, Eren proceeded to slit the throat of the first man and then lure the second into a trap. He then proceeded to sit on the man's chest and stab him over, and over, and over, and over again while screaming at him in a murderous rage. The brutality of the killing shocked the police, but they ruled it self-defense since the men were murderers themselves. Eren was nine years old at the time, and explained himself by stating they were merely animals that happened to look like people.
Goku delivers one to Frieza after going all out as a super saiyan, all for the people that he killed, in particular, Krillin and Vegeta.
In A Dame to Kill For, Dwight has Marv help him rescue Ava. As Marv is beating up the security guards, he notices Manute (who had given Dwight a No-Holds-Barred Beatdown earlier) among them and yells "You! You're the bum who hurt my pal!", before tackling him through a window and beating the crap out of him. After the beatdown, Marv sits beside Manute panting, he hears Manute gasp for breath, and continues beating him up. It is later revealed he also gouged out one of Manute's eyes. Let this sink in for a second. Marv is a badassdeterminator who has shrugged off bullets, cars, and all manner of attacks on his person, has thrown people through walls, and has generally proven to be Made of Iron and an Implacable Man... and he beats Manute up so damn badly he tires himself out.
That Yellow Bastard gives us the page quote. Police Detective John Hartigan saved 11-year-old Nancy Callahan from being killed by Roark, Jr., then was framed for the crime and spent 8 years in prison. After Hartigan is released, Roark gets ahold of Nancy again and tortures her. Hartigan doesn't take it well:
Marv gives a few of these in The Hard Goodbye. For the first one he uses a hatchet on the cop who killed Lucille and while its not shown Marv says that he took his time killing him and showed him pieces of himself. For the second one he knocks Kevin out, then saws his arms and legs off, then has a wolf eat his guts and finally saws his head off. We don't see the details on the final one but its implied that hes crushing or tearing out Cardinal Roark's throat or head, among other things.
Marv: (asked if killing a helpless old man will give him satisfaction) The killing, no. No satisfaction. But everything up until the killing will be a gas. You can scream now if you want to.
World War Hulk ended with the Hulk delivering this to Meik, his friend and ally when he confessed to being responsible for the death of Hulk's wife, his son (or so he thought), and a million other people; basically everything that had prompted the war.
X-Factor: 204 (v.3). Even an enemy's simulator knows that if you hurt/kill Rictor, Shatterstar's Roaring Rampage of Revenge would come next, quickly followed by your demise. A mini-version of this occurs when Shatterstar meets Cortex and realizes he's the one that possessed him and made him almost kill Rictor. He then chops off Cortex's hand. Hey, it pays to have a trained warrior as your boyfriend.
Out of context, The Punisher violently flinging a helpless woman against a shatter proof window over and over would seem like a Moral Event Horizon. Knowing that she's a ruthless perpetrator of a sex trafficking slave ring, responsible for the murder of an infant to torment the mother, and even worse things to the other captives besides, makes this an example of this trope.
In The Transformers IDW, Arcee was the first female Cybertronian, an unwilling test subject on introducing gender into a genderless species by the mad scientist Jhiaxus. As a result, she's a tad violent and takes out her fury on anything related to him or his experiments. When she finally finds Jhiaxus himself, he's been exposed to the Dead Universe, an alternate dimension that has the added ability of making those who have crossed over and back immortal (so long as they remain near the portal between the two). Needless to say, Arcee manages to gain some much needed catharsis from this state of affairs.
In one arc of Outsiders, Grace Choi is reunited with the pedophile who enslaved her as a child. She's since grown into a statuesque, nigh-invulnerable bruiser. It does not end well for him. One entire page is filled with panels of her fist going back and forth into his face, getting increasingly bloody as it goes on...
In the Firefly fic Forward, River does this to a Hand of Blue after he shoots Simon, which causes her to impale the Hand on her electrified sword, tear it free, and then stab him in the face until his head is reduced to the consistency of charred hamburger.
Harry Potter does this to Marcus Flint in the Enter the Fnords continuity of Top Dog, after Flint molests Hermione. Involves knives and being repeatedly shot in the extremities, in front of all his friends who are held back by a shield.
Stars Above: After multiple chapters of torment, Kagami finally beats Desideria to death with a bokken, and keeps going until the latter's body is nothing but a bloody smear on the pavement.
By the end of Yognapped's second installment, Peva has murdered Sips and forced the Yogscasters to aid in his release of Herobrine via a month of brutal mining. Once he tries to attack again, Lewis disarms him and beats the literal living hell out of him. He makes it last uninterrupted for over half of the day, tears off Peva's wounded arm with his bare hands, and remains completely silent throughout. And by the end, Peva's STILL ALIVE.
Rosario Vampire: Brightest Darkness Act II: Upon discovering that Miyabi had raped Mizore, Dark goes ballistic; when he gets the upper hand, Dark slowly crushes all of the bones in Miyabi's arms and legs to powder before tearing them off one by one, punches him in the face with such force that his jawbone snaps clean off, and finally tears his spinal cord clean out of his body with his bare hands. Even though Tsukune and co. all agree that Miyabi deserved every minute of it, they're still horrified at Dark's brutality.
There's also the time prior to that where Tommy catches Evan kissing his sister in the movie theater lobby. When Tommy stalks angrily towards them, a douchebag trips him for the hell of it. Tommy gets up, gives Evan a disturbingly sadistic look, and then proceeds to smash the jerk's face with a pole barrier and then pummel him mercilessly with his fists.
Curse of the Golden Flower: After the Emperor's youngest son kills the heir to the throne, his father pulls off his massive solid-gold belt and beats him with it, continuing to beat his corpse long after he's dead. His creepy little laugh doesn't help.
The Godfather: Carlo physically abuses Sonny's sister. Sonny then tracks down Carlo and attacks him in broad daylight. He uses his fists, his feet, Carlo's shoes, and a nearby metal trashcan (which is brought down smack on Carlo's head). All of this happens in public, and a crowd watches while Sonny's goons keep them from interfering. Carlo is left barely alive in a nearby puddle.
Layer Cake: anyone? The protagonist's cohort, Morty, an otherwise perfectly calm and stoic character, suddenly beats a former partner in crime half to death after having his berserk button toyed with just a little too much. Ten is a nice, round number, after all..
Poltergeist: A poltergeist has been terrorizing the house, and there's a horrible clown doll in Robbie's room that he just hates. Just when everything seems okay, the clown comes to life, sneaks up on Robbie, and attempts to suffocate him. Robbie overcomes the clown, throws it on the bed, and tears it apart, screaming, "I HATE YOU! I HATE YOU!".
Saw: After being captured, persuaded to saw off his foot to escape, and subjected to insane psychological torture, Adam screams his head off while bashing in his apparent captor's head with a toilet lid. Averted in Saw II, when Detective Matthews beats up the already-suffering Jigsaw. But Jigsaw has the last laugh.
The protagonist of Joshuu Sasori has a tendency to inflict knife wounds to people she really hates that are clearly painful but not immediately fatal, while silently snarling her contempt and loathing at them - over and over again, until her staggering victim finally keels over.
From Marie's perspective in High Tension when she manages to gain the upper hand against the killer and viciously bludgeons his face with a thick wooden stake wrapped in rusty barbed wire.
Vin Diesel's character in A Man Apart snaps and beats a man to death while he's supposed to be undercover.
The Hobbit: The Desolation of Smaug: In Mirkwood, Bilbo drops the Ring and finds that a smaller Giant Spidergrazed its leg upon it. Bilbo's response? Brutally stab the hell out of the spider in an Unstoppable Rage, before picking up the ring and going "Mine". He's visibly shocked after that, and ends up gazing at the Ring and the scene in horror.
In Ender’s Game, Stilson, a neighborhood bully, and Bonzo, a kid at Battle School, both try to do this to Ender and fail, (It's Personal, especially for Bonzo because he perceived Ender's winning as an insult to his honor), causing Ender to fight back and he actually kills both of them..
The same scene as above occurred in the original Godfather novel. The only reason that Sonny didn't beat Carlo to death was not because of the witnesses, but because Carlo meekly huddled on the ground and didn't even try to defend himself.
At the wedding in the beginning of the novel, the undertaker Bonasera came to Don Corleone to get justice for his daughter, who was viciously beaten by two young men after she refused to have sex with them. His request of "Make them suffer like she suffers" is depicted in excruciating detail as Paulie Gatto brings two ex-heavyweight boxers to help him out with the punks. By the end of it they are still alive, but the book says that they'd need several months of reconstructive surgery before they'd get out of the hospital.
In Solo Command, Gamorrean pilot "Piggy" saBinring is in the room when a gunman tries to assassinate Admiral Ackbar. After getting shot once, Piggy proceeds to pick up Ackbar's desk and promptly reduce the gunman's head to about a quarter of its proper width.
...and puts a sizable dent in Ackbar's (shipboard) office wall, with the dent also appearing in the cafeteria/lounge on the other side of the wall, hurling a hapless ensign halfway across the room while all but one of the other people in the room run for the door.
Also Corran Horn in I Jedi to a sadistic underling while Horn was going undercover in a pirate group. The man had done so many nasty things, including strafing crowded streets for fun, that when he finally pushed Corran too far he was beaten to an unrecognizable pulp. Made even better because he had been very handsome. And then to top it all off, the leader of the pirate group had him executed for insubordination and attacking a superior officer.
Artemis Fowl's bodyguard and manservant Butler in the first book of the series does this to a troll. At the height of the hostage crisis, the LEP send in a captured troll to force someone in the Fowl manor to cry for help, which could be taken as a sign that they're allowed inside. Butler runs headlong into the beast as it enters the building, and before he has much chance to do anything it eviscerates him and heaves him through a brick wall. He survives long enough for Holly to heal him with magic, and his subsequent takedown of the troll, using a mace and gauntlets taken from a suit of armor, is legendary.
Charmed has this of a sort with Chris in "Spin City." Having earlier been turned into a spider demon, he viciously confronts Leo, who mockingly asks why he hates him. Eventually, the taunts drive Chris over the edge; he throws Leo across the room, and then pins him down and absolutely pummels him all while screaming "You don't know me!" Even after being cured of the demon infection, he continues to beat on Leo, leaving his face bloody in the process, until Piper comes in and pulls him off. Through it all, Leo just lets him vent his frustrations and doesn't even try to fight back. However, since this is a different Leo from the one in Chris' time, one could argue that this was also a case of Misplaced Retribution.
Buffy tends to take out whatever anger issues she has at the moment on the vampires she hunts. She's occasionally called out for pummeling on them for much longer than necessary rather than simply staking them.
Hank Schraeder, after finding out the call drawing him away from the RV Jesse and Walt were hiding in was rigged by Jesse himself, Hank tracks Jesse down and delivers this trope. However, this gets him dismissed from the DEA.
Tuco's cousins, seeking to avenge Tuco's death. With a chromed fire axe.
Firefly: Episode 10, War Stories. Mal is captured by the elderly and sadistic Niska, is brutally tortured via electric shock, has his ear cut off, and is then killed painfully only to be resuscitated for further torture. When Mal's crew stages a rescue, Mal overcomes the guard and gives Niska what he deserves.
In Kamen Rider Kuuga, the titular hero pulls this off on a rather brutal Grongi. How extreme was the melee? It starts with him throwing the Grongi out the window and ends with him running the Grongi through with a sword. For added context, Yusuke Godai (aka Kuuga) is one of the straight-up nicest protagonists in the franchise, a friendly goofball whose introductory moment is him helping a lost child find their parents. When this guy tries to beat a monster's head to pulp against the pavement with his fists alone, you've got a prime - and jarring - example of this trope.
LOST: Hurley's beatdown of Sawyer after one too many fat jokes. Everyone just watches in amusement, even Jin. Averted, in that someone eventually intervened before things got out of hand.
A literal example on Merlin considering the episode involved an actual melee. After Arthur puts a stop to a protection racket going on in the local taverns, the thugs responsible go to a rather ridiculous extent to take their revenge: by using magical implements in a kingdom where it's forbidden (and punishable by death), murdering two noble knights in order to assume their identities, and entering themselves in the melee so that they'll have a better chance of killing Arthur in the chaos. All because he had them clapped in the stocks for a few hours!
The "Berserk Anger" and "Red Rage of Compassion" Limit Breaks in Exalted are essentially this; the Exalted in question flies into a rage and starts attacking blindly, without enough presence of mind to even draw a weapon. The main difference between the two is that RRoC is directed toward "sources of suffering", while Berserk Anger is directed towards anything and everything nearby, whether Friend or Foe.
Malfeas would desperately like to do this to all those treacherous gods, but he's kind of hell at the moment. No, he's not in hell. He is hell. But he need not worrying, his chosen are out to do the job of freeing him, and the charms he taught them all have something to do with EXTREME REVENGE, melee or not.
"Berserk Anger" returns in Scion - blow a Courage roll badly enough and you start killing everything between you and the nearest wall. Failing a Valor roll to that degree has similar results, but you aren't as likely to kill your friends.
You can do this yourself in the adventurer mode in Dwarf Fortress. A list of examples: Zamochit (Breaking every bone in the body, one by one), gouging your opponent's eyes out, biting, repeatedly pinching the face, ripping out teeth, or ripping of fingers. The point is, the combat system is extremely detailed and loaded with opportunities to do bad things.
In God of War, this is what you get to do to many Boss Fights, up and including Zeus himself at the end of the third and last game, where you can carry this out for as long as you want to your heart's content.
In Super Street Fighter IV, each character has access to Ultra Combos, which are performed using energy from the Revenge Gauge and can do massive damage with a full RG, rather than a half-filled one. The Revenge Gauge fills as your character gets beaten up. Some of the Ultra Combos are pretty brutal.
Deconstructed midway through Yggdra Union, when Yggdra finds and chases after Gulcasa while he and the Imperial Army are trying to retreat. Every time she catches up to him, she beats him viciously in battles where she is literally invincible until he manages to escape and run just a bit further away — and it turns out that having figured she would react thus upon seeing him, he'd decided to be living bait to draw her into an ambush. Yggdra falls into the trap face-first, and despite being in poor shape, Gulcasa leads the counterattack and mobs her into submission. The moral of the story is that letting your rage control you to tap into a few moments of brute strength is stupid stupid dumb when you're the hero of a strategy game.
Prototype's Alex Mercer encounters people-of-interest throughout New York City that have played a role in his clouded past. Upon capture, Alex can immediately chokeslam his victims and viciously deconstruct their face into a pool of blood with his bare fists before absorbing them and their memories. What makes this into an example of the trope is that later on, you do it to someone very specific. After all of the damage they caused, getting your own back and seeing Greene getting liquified like this, even with the same animation as everyone else, is intensely satisfying.
When you think about it, Sonic the Hedgehog does this to Erazor Djinn's One-Winged Angel form Alf Layla wa Layla in Sonic and the Secret Rings. Consider this: he just watched his only companion in the entire game get temporarily killed, and because of Erazor's mistake, he absorbs the World Rings of Hatred, Sadness, and Rage and becomes Darkspine Sonic. The entire level consists of you flying up to Erazor, kicking his own big ball of energy back at him, and then rushing in to beat the crap out of him with your bare hands. Also doubles as a Roaring Rampage of Revenge.
At the end of Battlefield 3, Blackburn has already been through hell, but the sight of Solomon killing Montes, his best and last remaining friend, finally throws him over the edge, prompting him to choke the guy half to death with his handcuffs before beating his face in with a brick.
The Last of Us: After a rough Boss FightEllie makes damn sure David won't be getting up again via machete; the impression is that the hacking would have continued until complete exhaustion if not for Joel's interruption.
In Resident Evil 5, don't stand behind the Executioner when he's recovering from a stagger, or he'll cut you down with his Spin Attack.
When Simmons downshifts back into human(ish) form and is vulnerable to melee attacks, Leon, Ada, and Helena will all drop the flashy choreography and just run up, knock him down, and beat the living shit out of his face with their bare hands, each of which ends with a windup punch that knocks him flat. You can practically taste the rage they put into each blow.
In Grand Theft Auto V, this is basically the only responseTrevor has to someone doing him wrong. Betray him in a business deal? Insult him (or worse, his mother)? Point out the fact that he's a psychopathic monster? Prepare to end up a puree on the street. Of course, he's equally proficient with machine guns and shotguns, as well as the standard running your ass over, but if at all possible he gets down and dirty.
In Episode 8 ("In Harm's Way") of The Walking Dead, Kenny receives a severe beating from Carver that ends with him losing an eye. Mere hours later, he returns the favor. With a crowbar. The latter's face is pretty much gone by the time he gives up.
In the Homestuck animation "[S] Make Her Pay", Aradia gets her revenge by viciously beating the Blue Blood out of Vriska. She only relents after seeing Tavros's horrified reaction. We later learn that this beating was severe enough that it resulted in Vriska's death, though Vriska was prepared for that and used it as an opportunity to ascend to God Tier.
Later played for laughs with Post-Scratch Jack Noir beating up a prison guard. After 7 knives in the back and the 89th head bash into the wall, Jack decides that he is sorry for the overkill. And by "sorry", he means "bored".
That was the second beat-down. The first came at the hands of Airman Higgs after Zola made the mistake of pissing him off. Higgs is also known as "The Unstoppable Higgs", and there is a VERY good reason for that; The only reason that Zola was still alive at that point was because she was doped up on Psycho Serum.
Dellyn Goblinslayer of Goblins kept a female yuan-ti named Kin as his plaything and routinely abused her to within an inch of her life. Minmax and Forgath get into a bar fight with him and manage to gruesomely beat him, at which point Dellyn stabilizes at -6 hitpoints. As a high level ranger, if he recovers, he could track them down and take his revenge, so as they argue over whether or not to kill him while he's unconscious, Kin picks up Minmax's broken sword and stabs Dellyn under the jaw. Then she stabs him again. And again and again...
In V4 of Survival of the Fittest, Jimmy Brennan gets revenge on school bully Phillip Ward by beating him to death with a piece of driftwood, and continues to pummel his head in long after he's died.
In Entry #67 of Marble Hornets, Tim, as his masked persona, repeatedly punches Alex, who is tied to a chair and thus helpless to fight back because of everything the latter has done to make the former's life a living hell.
Peter beats up Jimmy Fallon (who was the SNL host) for all of the horrible sketches he's done. Fallon had slept with his daughter and used the sex as an opening sketch. This is one of the few times Peter actually does show some care for Meg. Of course when he beats up Fallon its for the aforementioned reason before asking for the man who slept with Meg.
Brian doesn't pay Stewie the $50 he's owed. In retribution, Stewie smashes a glass over his head, shoots him in the kneecaps, shoves him down a flight of stairs, and sets him on fire, all while yelling, "WHERE'S MY MONEY"?.
Brian gets a similar beating from Quagmire; Brian has sex with Quagmire's father who recently had a sex change operation. Amazingly, Brian still comes out on top in the end: as Quagmire leaves, Brian says, "Hey... I f*cked your dad." and slams the door. Brian didn't even know that was Quagmire's dad, and underwent a massive squick reaction before Quagmire came and beat him up, making it a literal and figurative case of Kick the Dog.
In the Stroker and Hoop episode "I Saw Stroker Killing Santa (a.k.a. A Cold, Dead, White Christmas)", Santa Claus keeps shooting repeatedly at the guy who tried to kill him, continuing after he is totally dead.
There was one story from The American Civil War in which some skirmishers were shooting at each other. Two soldiers inexplicably conceived an animosity toward one another above and beyond mere military duty and would repeatedly exchange shots while insulting each other. The soldiers decided to call an ad-hoc truce so they could solve it with a brawl as was due and proper. Once they had done this, everyone shook hands and went back to the business of killing one another like gentlemen.
A man named Richard Lawrence attempted to assassinate President Andrew Jackson after the President attended the funeral of a Congressman. Lawrence drew two pistols and aimed at the president at close range, attempting to fire first one, then the other. Both pistols misfired in spite of later tests proving them to be in proper working order. Jackson noticed Lawrence, spotted the pistols, and was clearly displeased when he drew the logical conclusion from the situation: a stranger pointing two guns at a government leader. Jackson, a former Army general of the War of 1812, was also known to be a man of fierce temper, swift action, and substantial vulgarity. As he was 67 at the time, the President regularly walked with a cane, but in this case, he closed on Lawrence with said cane in his grip, and proceeded to beat the bloody stuffing out of the would-be assassin. After some moments, assistance finally arrived (including Davy Crockett himself) and they intervened... to hold Jackson back so as to keep him from reducing Lawrence into a thin red smear on the floor. Crockett and the others succeeded in keeping Jackson from bludgeoning Lawrence to death on the spot, whereupon they piled onto the now-injured Lawrence to apprehend him as a criminal.