Courage the Cowardly Dog had this inflicted onto Courage in the Villain Ball (No, not thatVillain Ball) episode. Basically, all of the major antagonists team up and play a dodgeball match with Courage, Courage being the only one not throwing the ball.
There's also the Mecha Courage ep where he's pitted against Dai Lung's robot dog in the Roman Colosseum. The match is largely one sided, and during one particularly painful instance, the robot doesn't even give Courage the chance to finish saying his 'the things I do for love!' catchphrase. Ironically Courage manages to win because he outlasted the robot till it's batteries died.
The poor dog had this happen to him too many times for his own good. Other examples include the embittered Kitty and a sad Goat venting their anger onto him for their personal tragedies. Only thanks to (partial) cartoony rules is that character still alive and well.
Teen Titans: Slade almost kills Robin this way in the episode "Haunted." To the point that Robin, who is otherwise alwaysDefiant to the End, actually begs Slade to stop. But you know what the worst part was? It was all in Robin's head. Which means that all the damage HE DID TO HIMSELF.
You had a strong male-on-female version as well in season four, when Slade kicked the crap out of Raven, mindraped her, all the while musing on how "it's always the quiet ones".
In The Movie, Robin brutally attacks and supposedly murders Saeko-Tek.
Frequently in Justice League, especially in later seasons. In JLU's second season finale, Superman's fight against his robotic double briefly turns into him delivering one to himself.
Superman: I'm NOT like you! I'm NOTHING like you!
Bruce Timm justified the show's tendency for fist fights between the characters by saying that getting up close and personal is what would likely happen when you put a bunch of people who hate each other into a room together.
Superman delivered two of them in the two-parter Twilight (of the Gods). The first is when Darkseid arrives on the Watchtower, and the rest of the League has to physically hold back Superman to let Darkseid say why he was there. Later, at the end of the second part, Superman and Darkseid face off, and Superman was actually keeping his promise of not stopping until Darkseid was "a greasy smear" on his fist.
Metallo gives one of these to Superman in The Batman episode "The Batman-Superman Story Part 1", and would have killed him with his Kryptonite heart until Batman got a hold of it. Superman then effortlessly kicks his ass.
The Question gets one of these at the hands of Lex Luthor, of all people, while attempting to avert a bad future in the Unlimited episode "Question Authority". Luthor's newfound Super Strength just makes it worse, because he is clearly enjoying brutally attacking his would-be assassin.
This time Wonder Woman under mindcontrol delivers one of these to Hawkgirl, Black Canary, Vixen and Huntress. Just the Oh, Crap! look on their faces when they see her says it all. "Anyone got a plan?" "Yeah, try to stay alive."
In Batman Beyond: Return of the Joker, specifically the flashback, Batman gives Joker a severe beating, enough to actually make Joker bleed at the mouth, grab him, throw him out of the room, and then grab him and slam him against one of the block pile's faces and utter in a very chilling voice "I'll break you in two...!", all after the Joker showed Batman a "family memories" video documenting the three weeks of electrocution and serum based torture to make Robin go insane to the extent where his entire speech was composed of nothing else butinsane laughter, reveal everything he knows about Batman (including his Secret Identity), and then giving him a makeover to make Robin resemble a crude imitation of the Joker called Joker Jr. In fact, because of this, he almost ended up breaking his one rule by killing The Joker as a result.
It's fair to say that Batman is the king of this trope.
Batman: Under the Red Hood is rife with them. Flashbacks show Robin beating mooks to the point that even Batman is alarmed. In the same film, Batman gives an epic one to Jason Todd, who just finished giving one to The Joker with a crowbar.
At the start of the same film there's a brutal one from Joker to Jason Todd with him pummeling him to bloody pulp with a crowbar (his beating to Joker later in the film was meant to mirror this) to the point where he can barely move and then leaves him to get killed by a bomb. Batman attempts a rescue, but arrives too late.
In Batman Beyond: Terry McGuinness as Batman does this to one of the Splicers. To be fair, Dr. Cuvier shot him up with vampire bat serum, so he wasn't quite human at the time.
Superman/Shazam!: The Return of Black Adam gives us several fights through the course of its 20 minute run time, and while many of them favor one opponent or another, you can't call any of them truly one-sided. At least not until Black Adam offers Captain Marvel a Sadistic Choice between sacrificing himself or letting a hostage die, and then tries to kill the hostage anyway. Superman saves the hostage, and Cap then delivers unto Adam a profoundly one-sided beat down, defeating the villain in the space of 5 quick attacks.
The first thing Megatron does after getting his body back in the first-season finale of Transformers Animated? Take down Optimus, Prowl, and Bulkhead. The second thing he does is take Starscream down with one strike of the AllSpark key.
Transformers Prime: Optimus Prime gives one to Megatron in One Shall Fall. Optimus knocks Megatron off a cliff, then jumps after him and grinds his wheels into the Decepticon leader's face, blinding him. After that, Optimus proceeded to beat the crap out of Megatron and nearly killed him too.
A couple of Vehicons decided to have some fun beating up an amnesic Optimus/Orion who begins to doubt and protest against Megatron's plans. This backfires on the Vehicons as the beatdown causes Optimus/Orion to unconsciously activate his arm cannons (which he didn't know he had) to defend himself.
Ben 10s Vilgax dishes these out like there's no tomorrow, examples include every freaking time he fights Ben, with the best being the time he destroyed Mount Rushmore with Ben's face.
Ben himself deals out a fierce beatdown to Aggregor in Ben 10: Ultimate Alien after said villain killed the Andromedan aliens to gain their powers. Ben (as Humongosaur, no less) goes absolutely berserk, and it takes Gwen's intervention to stop Ben from outright killing him. Unfortunately, it turns out that Aggregor's new form is Nigh Invulnerable, so Ben couldn't have harmed him much anyway.
In an episode of American Dad!, Stan receives the beating of his life from childhood bully Stelio Kontos. Steve receives the same later on in an off-screen moment.
Roger is often the show's primary victim of such beatdown, most of them administered onto him by Stan. Sometimes Roger deserves such beating and sometimes he doesn't depending on the episode. Apparently Stan does not believe that he is committing assault when he assaults Roger since Roger is an alien and not human and Stan often beats up Roger even over the pettiest of grievances such as in "Not So Desperate Housewives" when he abuses Roger and throws him through a wall because Roger was forming a friendship with a dog named Fussy, who Stan was also trying to bond with. Stan always gets away with beating up Roger except in "Seasons Beating's" when he gets in trouble for beating Roger up in a public mall and gets kicked excommunicated from the church as a result.
Several episodes featuring Peter against Ernie the Giant Chicken.
In "Into Harmony's Way," Peter – annoyed at a simple request by his boss to complete some reports before a 5 p.m. deadline – beats the crap out of his boss.
In "A Fistful of Meg," her tormenter, Mike, initially does this (before Meg gets the upper hand).
In "Road to Rupert", after Meg had enough of being humiliated by Peter and his friends, she stops the car she's driving them in and immediately gets rear-ended. When confronted by the hostile driver of the vehicle behind her, she proceeds to beat the living hell out of the guy.
In "Dial Meg for Murder", Meg comes out of jail as a hardened psychopath and gets revenge on her abusive family and classmates. In it, she beats the crap out of Peter twice and beats up the popular kids with a pillowcase full of unopened sodas.
In "Quagmire's Dad", Quagmire administers a brutal beat-down to Brian after he finds out that Brian had sex with his father but Brian didn't know about this fact.
Quagmire himself gets a pretty brutal one from his sister's abusive boyfriend in "The Story Of Brenda Q.". It's one of the most terrifying moments in the show's history.
In "The Tan Aquatic", Chris is being bullied by Kyle, another boy. In a rare moment of responsibility, Peter attempts to discuss the situation with Kyle; only to be verbally abused by the 13 year old. Peter snaps and gives Kyle a pretty brutal beatdown. Also a bit unusual for Peter, he understands that he's in serious trouble:
Brian: Is something wrong?
Peter: No, No. Everything's cool right now. Might be some problems later, but we'll cross that bridge when we come to it.
Peter: I'm going to prison, aren't I?
In "Peter's Daughter", Peter unexpectedly shows up at Meg's school after she's been mocked (again) by Alpha Bitch Connie D'Amico. Peter proceeded to grab Connie by the head and repeatedly bash her face into a fire extinguisher case with an increasing amount of force until Meg was able to stop him. He then dropped Connie into a bloody puddle on the floor as Meg led him away, sobbing the whole time.
In "The Fighting Irish", after Peter bites off more than he can chew by bragging that he can beat Liam Neeson in fight, only to for eponymous actor to essentially make Peter his slave, after they actually meet and Peter is left begging for mercy, only to finally try to put his money where his mouth is after finally having enough Peter punches Nesson in the face. What follows is an epicCurb-Stomp Battle, where Nesson punches, throws, and kicks Peter all around his trailer, at one point even managing to embed Peter's head into his ceiling and pumble his hanging body until he finally falls out and Nesson finishes him off by breaking both his hands and kneeing him in the nose so hard, he goes flying into a nearby dressing-mirror. Ouch. Though at the very least, Peter's friends were still impressed he had balls to even try.
In the same episode, when Spongebob suggests to do some kicking, Patrick kicks Sandy hard on the butt. Sandy gets very angry and chases him outside with a trombone (Cue Scream Discretion Shot.)
In "The Fry Cook Games", Spongebob and Patrick's friendship is shattered once again when Mr. Krabs and Plankton turn them into aggressive sociopaths bent on killing each other. In the final event: Bun Wrestling, they both engage in a vicious, violent, heavy brawl... until they both realize how their actions are affecting their friendship, and that friendship is more important than wanting to win very badly, much to Krabs' and Plankton's dismay.
In Teenage Mutant Ninja Turtles, the Foot Elite deliver one of these to Leonardo at the climax of "The Shredder Strikes Back", leaving him near death. Another occurs in "Exodus, pt. 2", where a souped-up Shredder (with some assistance from Karai) delivers one of these to the four turtles, leaving injuries that took several episodes to heal.
Just to get the point across, the Turtles are so badly beaten that the only way they can "win" is to set the ship they're on to self-destruct and take the Shredder out with them. Fortunately, the Utroms show up in time to save them.
In the 2012 series, the first time time the turtles face off against the Shredder, he severely beats the tar out of them. Highlights include: throwing Raphael into a sign, electrocuting him, and Michelangelo being crushed underneath the sign wreckage. The only reason the turtles escape alive is because the Shredder gets distracted by Bradford and Xever mutating into Dogpound and Fishface.
In the Season 1 finale, Splinter delivers one of these to the Shredder in an animal rage, leaving him in a heap on the floor. Shredder returns the favour in the Season 2 finale.
In The Simpsons, a School Fair is advertised has being the "Happiest Place on Earth", causing Disney Lawyers to harass Principle Skinner, and threaten to sue him. At which point, Skinner breaks out Green Beret training, beating the tar out of the Lawyers, and when one flees, hurling his briefcase at him and knocking him out. He caps this off with "Copyright Expired"
In the episode, Homie the Clown, Homer pummels the shit out of the HamburglarExpy, the Krusty Burglar, while doubling as Krusty.
In the South Park episode "Breast Cancer Show Ever", after Cartman keeps making fun of breast cancer, Wendy decides to fight him after school. Cartman spends most of the episode trying to get out of the fight while saving face in front of his peers, because he knows this is going to happen. Ultimately he fails and gets his ass handed to him in front of the entire school.
Cartman got another one in "Stunning and Brave", when he threatens to frame PC Principal (seriously, that's his name) for having sex with Butters in order to get out of the four days detention he was given earlier. Things went downhillfast. Notably, PC Prinipal didn't even seem to care one bit that he was being framed for paedophilia. The whole reason he gave Cartman a beating was because he ended his threat with "capisce?", which PC Principal considered racist because it associated Italians with intimidation tactics. The beating only got worse after Cartman referred to Jared from Subway as a "spokesman" rather than "spokesperson"
In one example, our trio of heroes strike a deal with baddie Mojo Jojo, but when he betrays them, they beat him to a pulp. They only realise how far they've gone when they notice a tear fall from one of his swollen eyes.
In "Granddad's Fight", Robert Freeman is so full of hate and rage for Colonel Stinkmeaner for wrecking his stuff, hurting his knee, and making him a laughing stock of the entire town, that before Mr. Stinkmeaner can land a single hit on him, Freeman proceeds to beat the tar out of him, landing blow after blow until the final punch knocks him to the ground. After the fight is over, they discover that Stinkmeaner died from the beating and Robert feels bad about it.
In "Let's Nab Oprah", Huey delivers one to Riley when he finds out that his friends Ed and Rummy are going to try to kidnap Oprah, and he's going to accompany them. Twice (the second time was more revenge related for having security sic Bushido Brown on him).
In "Attack of the Killer Kung Fu Wolf Bitch", Granddad's date Luna says that she's a master of White Lotus Kung Fu. Huey doesn't believe her, saying that there are no masters left of this ancient art. He asks for a demonstration, and Luna proceeds to beat the daylights out of Huey. After the fight, Huey walks back to the bathroom where Riley and Granddad were hiding from Luna, and drops to the floor and passes out.
In "Stinkmeaner: Begun the Clone War Has", the clone of Stinkmeaner comes to annoy Robert. Wuncler finds Stinkmeaner's treatment of Robert hilarious, and starts a fight tour. Robert is told to hold onto his hatred of Stinkmeaner by Riley, and spends most of his time training, and when the fight finally occurs, Robert beats the living tar out of him yet again in a manner that would make most MMA fighters jealous, reducing the clone to a sobbing, bloody mess on the ground. If it weren't for Huey stepping in, he would've killed him again.
In the Pinky and the Brain episode "Welcome To The Jungle", Brain delivers one to his arch enemy Snowball when he tries to sacrifice Pinky.
Megas XLR. Name any episode. Chances are Coop has beat the living daylights out of someone in it.
One classic Disney short, "The Art Of Self Defense", has Goofy receiving one of these for pretty much the whole short, from various exercise equipment and his own shadow.
In episode 13 of The Legend of Calamity Jane a mascara-sporting villain beats Calamity Jane to within an inch of her life. She spends most of the episode trying to recover from the vicious attack.
In an episode of Metalocalypse the normally kind and child like Toki has a really bad day, when they attend a concert a fan won't stop screaming in his ear eventually he has had enough and viciously beats him to death in a fit of rage, everyone is shocked and terrified by this including Murderface who planned to beat him for registering all Planet Piss websites and making them into beastiality sites. Starring Murderface.
We have Giant Man pounding the living daylights out of Abomination just as the villain was about to squish Wasp.
Captain America delivers a particularly epic one to the Skrull that had impersonated him and marred his image by manipulating and betraying the other Avengers and proclaiming to the world that they should surrender to the Skrulls. Needless to say, it's very satisfying.
Cat and (sometimes) Dog usually receive this from the Greasers in CatDog.
Celebrity Deathmatch: Gandhi inflicts one on Genghis Khan during their fight, and Genghis fails to fight back.
Gravity Falls: Season 1 finale "Gideon Rises" has a surprisingly violent moment in which Dipper dives off a cliff, crashes through the windscreen of a giant robot, and brutally beats the shit out of Gideon.
Samurai Jack: In the episode "Jack in Egypt", the instant Jack realizes the Minions of Set have been released they come out from behind the black and deliver a savage, relentless beat-down that leaves Jack covered in bruises and gashes within the first ten seconds of the fight. He spends the rest of the episode running in terror, receiving more beat-downs along the way.
His fight with the Guardian starts out more or less even, but after Jack ruins the Guardian's suit he receives a beatdown that leaves him a broken mess. If it weren't for the intervention of the time portal the Guardian was protecting, Jack would have been killed.
Beware the Batman: Batman's first encounter with Killer Croc ends with Croc beaten within an inch of his life.
Tenzin's fight with Zaheer in Season 3 of The Legend of Korra becomes this when the rest of Zaheer's gang arrives and beats Tenzin senseless.
Steven Universe: In "Crack the Whip", Jasper gives one of these to Amethyst.
Kaeloo: Once an Episode, Bad Kaeloo does this to Mr. Cat as punishment for whatever evil things he did through the episode.