Ender knew the unspoken rules of manly warfare, even though he was only six. It was forbidden to strike the opponent who lay helpless on the ground; only an animal would do that. So Ender walked to Stiltson's supine body and kicked him again, viciously, in the ribs.
A favorite tactic among the cast of Code Geass, but especially Charles, Lelouch and Schneizel. Suzaku has his moments as well. This is probably because most of the cast are well-intentioned extremists running on generations of fervent nationalism and racial wars. It's not a fun place.
Yu-Gi-Oh! - Yami Yugi of all people does this to Insector Haga (of all people). He kept attacking Haga with Berserker Soul even after his Life Points hit zero, and would have kept going if Anzu hadn't stopped him.
While it might still be unjustified, Insector Haga had pulled a cruel trick on Yami (which was also this trope) so in a way, he kind of deserved it. Yami just went a little too far.
Nnoitra did this to Ichigo in Bleachjust after Ichigo defeated Grimmjow. Nnoitra then received a Karmic Death thanks to someone who presents more of a challenge than a half-dead Ichi: ZarakiKenpachi.
Also done by Gin towards his Morality Pet Rangiku. He faked it. Kira Izuru claims this is one of the main strategies of the third division. Then again, even Rukia advised Ichigo to follow the attack from behind mantra.
Beelzemon does this to an already-wounded Kyuubimon in Digimon Tamers when she makes the mistake of referring to him as Impmon, while pleading with him to stop his attack on her and the other protagonists. Seeing as Kyuubimon is a 4-legged, 9-tailed fox, it could also be considered a literal example of Kick the Dog.
Miata in Claymore is clearly established to be insane after she keeps stabbing a dead Yoma after (quite viciously) killing it. However, it might just be that she doesn't realize it's dead, as she's just a bit off her rocker.
Spandam in his arc in One Piece does this to Nico Robin after capturing her, all the while gloating about the genocide at Ohara, that happened when Robin was 8 and that she was the only survivor of. (Also to Franky, albeit to a lesser extent.) He even kicks poor Robin down the stairs, and somehow his small Draco in Leather Pants fandom mostly doesn't mind and considers that to add to his perceived sexiness.
Baccano! - Ladd Russo demonstrates just what a crazy bastard he is when he decides to take a whack at a downed opponent not once or twice but forty-seven times, entirely for shits and giggles.
In Pokémon Special, Maxie and Archie love doing this. They left Courtney's corpse underneath fallen rubble (they pulled her into it first), had Norman's dead/dying body go up in flames, beat the shit of Wallace after he was forced to stand down to save his love interest, and stomped on Ruby's Feebas several times over. Though it should be noted that they'd been driven insane by the power of the Red & Blue Orbs and so might not have done this sort of stuff prior...
After Alder's Accelgor is all but barbecued by a seriously powerful fire attack, it weakly limps to what it thinks is its trainer calling out to it and offering it healing. Turns out it's really a Zorua using its Illusion ability. The Accelgor cries.
Team Rocket in Pokémon did this to Ash's Sceptile while it was having a Heroic BSOD, having Cacnea and Seviper hit it over and over with Poison Tail and Needle Arm because it couldn't fight back while trying to protect the Meganium that it had a crush on.
Ash and co aren't immune to this either. Even when the trio were on the verge of surrender or retreating, the heroes would insist they hadn't suffered enough until barraging them enough to initiate their usual "blasting off". Subverted in Best Wishes, even when they try to do it, Team Rocket usually use their jet packs to make a successful escape.
A variation: In the Japanese version of Yu-Gi-Oh! GX, when Edo Phoenix defeats Judai, with an attack so powerful it sends Judai flying and renders him partially blind, Edo roars, "Dissappear, trash!"
A newly evolved Level 2 slashed Kanda severely after disguising himself as an accompanying Finder, after punching Kanda through several walls and then holding him pinned to another wall.
Tyki has done this twice. Firstly when Allen was completely worn out from trying to save Suman and had injuries to both his arms, when Tyki seemingly destroys Allen's Innocence and then plants a flesh-eating golem to bite a hole in his heart, meaning to kill him - well, he had been sent to assassinate Allen. Secondly in the Ark arc, when Tyki's alternate form is triggered and he wipes the floor with Allen and Lavi. He beats them up and then sets to choking Lenalee, who is unable to fight back effectively due to her injuries from an earlier battle, to near death.
In Ranma ˝ several characters will do this. For example Genma and Soun both will attack Happosai when he is down. Of course, Happosai usually deserves it.
In Black Lagoon, Rock is the victim of this when Chaka is trying to provoke his bodyguard and partner Revy into a quickdraw duel, so punches him in the gut and starts taunting and kicking him whilst he's on the floor writhing in pain and gasping for breath, until their bosses arrive.
In Dragon Ball Z, Goku defeats two members of the GinyuForce very easily, leaving them lying on the ground unconscious or in serious pain but still alive, not killing them even though they came very close to murdering his son and best friend (and alsoVegeta). As he and his friends discuss the events on Namek, Vegeta suddenly murders both weakened fighters. Goku chews him out for this, saying they were no threat and couldn't even defend themselves but Vegeta (unsurprisingly) doesn't care.
The fight between Vegeta and Frieza has plenty of this too. Even after beating Vegeta so hard he couldn't move, Frieza picks him up by his hair and gleefully continues to beat the hell out of him.
Also, back in the 22nd Tenkaichi Budoukai, Tenshinhan beats Yamcha by landing a powerful kick to his gut. The two were in mid-air when it happened, so after Yamcha fell back onto the ring, Ten decided to land a kneedrop onto Yamcha's leg, breaking it. Goku calls out Ten on this, but Ten simply shrugs him off.
Lest we forget about the Spopovich vs. Videl fight, when Videl finally manages to concede that she's in over her head against the magically-enhanced Spopovich and lets herself get thrown out of the ring... only for Spopovich to grab her leg in mid-air and toss her back in, returning her to a Curb-Stomp Battle that seemed to be doing its damnedest to rival the aforementioned Frieza vs. Vegeta example in sheer brutality.
In Berserk, Guts does this to the Apostles whenever he defeats one. He casually shoots the bisected but still alive Baron full of crossbow bolts, and stabs the mutilated Count in the face dozens of times with a knife (which still doesn't kill them). The fact that the Apostles themselves commit far greater crimes on a regular basis and against helpless people is the only thing that prevents it from being a Moral Event Horizon for Guts, but it certainly shows how twisted and blackened his soul is following the Eclipse.
Subverted in the last episode of Speed Grapher. Suitengu Choji is not well known for his mercy, but when Saiga sacrifices his eyes to blow up a missile that would have killed them both, Suitengu takes pity on the helpless man and flies him to safety before taking his farewell bow.
Done to Sting in Fairy Tail. After experiencing a Freak Out over what looked like the death of his closest friend, Minerva informs him that she actually saved him in time. When Sting starts crying all over again and thanks her, she snaps at him for crying and lets him know that she's actually holding Lector hostage until Sting helps them win an ongoing tournament, going as far as to threaten to kill him if Sting tries anything. Considering that they were already allies. Sting is understandably shocked by this.
Happens in Vagabond after the rematch between Musashi and Inshun. Subverted as Musashi was actually only hitting the ground next to the unconscious Inshun.
Ian from A Cruel God Reigns has a pretty long spurt of this. First, he borderline Mind Rapes Jeremy to get him to confess to tampering with Greg's car, which kills both Greg and Sandra even though Jeremy is obviously having trouble dealing with his mother's death. He then does it again after Jeremy confesses to tampering with the car, but also to the fact that Greg had been beating and raping him, but this time accuses Jeremy of lying about the entire thing, saying that the car must have been dysfunctional. Luckily, Ian eventually turns Adopt the Dog after his My God, What Have I Done?.
Lunatic from Tiger & Bunny has a habit of doing this to the criminals he executes when they are already arrested, defeated or otherwise neutralized such as the prisoners he killed in episode 6 and Maverick after he wiped his own mind.
Legion Of Super-Heroes - In "Five Years Later", the serial killer Roxxas (no relation) was attempting to kill the Legion when he found Mekt Ranzz, the villainous brother to Legionnaires Lightning Lad and Lightning Lass/Light Lass. Believing him to be after the Legion, Roxxas tries to strike a deal, splitting up the Legionnaires they could kill; when Mekt, who has reformed, tries to stop him from killing, Roxxas brings him down and, complaining that he would have shared, kicks him while he is unconscious.
In Watchmen, Rorschach is kicked and beaten after he's been pinned down by the police, having already injured himself jumping out of a second-story window while trying to evade capture. Of course, he did severely injure at least a few of them before being brought down, and has been said to have made some insulting remarks about the police.
Hollis Mason's murder is another example.
Usagi Yojimbo - A favorite tactic of Noriko "The Blood Princess". She's introduced sparring with her cousin Tomoe using wooden swords, winning, and then savagely beating a now unarmed Tomoe to the ground. She does this again (minus the wooden swords) when she reveals that not only are she and Tomoe half-sisters but she also killed Tomoe's father after he refused to acknowledge her as his daughter, literally kicking Tomoe while she's down and in shock.
The Ultimates - In Ultimate Extinction, Mahr Vehl asked Captain America if he had a problem with kicking people when they were down. The Captain coolly replied he always figured it was best time to kick them.
TFN Fan Films hosts a short Star Wars fan film named Legacy of the Jedi produced by Thrill Factory Entertainments in which a Jedi uses this to recover his fallen Master's lightsaber after a lightsaber dueling session in which the Jedi and his Apprentice are evenly matched by a Sith Master. Watch it here: 
Biff did this in Back to the Future Part II. After Marty is knocked over in 1955, Biff takes the sports almanac back. He then kicks Marty in the stomach twice, the second time saying "This one's for my car!" Marty was lying on the ground, but he was still conscious.
While we're at it, how about Lex Luthor viciously kicking the ever-loving crap out of Superman in Superman Returns?
And Davy Jones in the third Pirates Of The Caribbean, stabbing Will Turner after he's both defeated and fearing for Elizabeth's life — with the sword Will made in the first film, no less. Jones gets his just deserts a few minutes later.
Kung Fu Panda. In the climactic battle, Po has thoroughly beaten Tai Lung physically and emotionally, with obvious wounds on the villain as he struggles in helpless bewilderment towards Po to ask how this is all possible. Instead of answering, knocks him out and sends him sailing. *
might still happen. Even so, and even taking into account that humiliating Tai Lung might be the only way to beat him (turning the strength of his pride against him), this could very well count as some serious Moral Dissonance.
The Joker does this with gusto to Bats in The Dark Knight, with a crowbar after he had just been attacked by a pack of Rottweilers. Possibly justifiable there, as... well, he is the Goddamn Batman — he doesn't stay down too easily.
Mitch tries to do this to Slim in Enough. Fortunately for her, her self-defense teacher had prepared her for this situation.
Instructor: He's standing over you. He thinks he's won. And as sure as he's a coward, he will try to kick you.
Sonny Corleone's death scene in The Godfather. Not only did he get shot dozens of times, even when he couldn't defend himself, but his dead body gets shot a few more times just because and then kicked hard right in the face. This mirrors his No-Holds-Barred Beatdown of Carlo earlier on, which he ended by kicking Carlo into the gutter (it's Carlo who sets him up to be killed at the tollbooth, by pushing the same Berserk Button as before).
This happens in Im Gonna Git You Sucka. After two minor villains are disarmed and no longer resisting, Jack Spade punches one of them in the stomach (watch it on YouTube at about 3:10). Jack's partner John Slade has to tell him to stop ("Hold it! Hold it! It's over, it's over!") or the villain would have been much worse off. Jack has no combat experience and was caught up in the heat of battle.
A favorite of mob movies beatdowns, kicking a person who's already on the floor is a good way to showcase the brutality of the characters doing the kicking. Most memorably used in the Billy Batts scene in Goodfellas where Robert De Niro and Joe Pesci just batter the hell out of their victim. Also in the famous pen scene in Casino, where Joe Pesci alternates between kicking and repeatedly stabbing his target with a pen even though he's already on the ground.
Remarkably enough, this is averted by the jerkass protagonist of Royal Flash, whose motto is "Never kick a man when he's down; he might get up."
In Streets Of Fire, this is done to the hero, Tom Cody, by Big Bad Raven Shaddock. Cause he's awesome, Cody pulls through and wins the fight anyway.
Jerk Ass Master Li from the 2010 remake of The Karate Kid encourages his students to do this to their opponents, even when they are already down and defeated, showing them absolutely no mercy.
In Unforgiven, "Little Bill" Daggett does this when dispensing justice on out-of-towners. He beats and kicks English Bob as well as William Munney for coming to town as hired guns.
Undercover Brother. The title character kicks a golf course security guard after Sistah Girl knocks the guard out. Later in the film, he apparently literally curb-stomps a knocked down guard... only to reveal that he in fact crushed the guard's bag of Cheetos. It was his last bag.
In Godzilla Vs Destoroyah the eponymous villain waits until Godzilla is grieving over his son's death, than attacks him, establishing itself as one of the most hated monsters in the franchise.
In Revenge Of The Sith, Palpatine orders Anakin to execute the literally disarmed Count Dooku after Anakin defeated him. After a moment of hesitation on Anakin's part, Palpatine commands him to do it — slipping into his Darth Sidious voice in the process — Anakin beheads Dooku. This act serves the double purpose of removing a no longer useful pawn and bringing Anakin ever closer to the Sith way of thinking.
In the live-action Transformers film, Optimus Prime's fight against Megatron doesn't end up going too well, with the Decepticon leader being more powerful than Prime. One portion of the fight shows Optimus on his knees, wounded. Megatron takes the opportunity to kick him in the face.
Transformers: Revenge of The Fallen features a three-against-one fight with Optimus Prime facing a resurrected Megatron, Starscream and Grindor. Midway through the fight, Optimus ends up receiving a devastating amount of punishment, resulting in a Broken Faceplate. Just as he begins struggling to get back on his feet, Starscream hits him... with a missile.
In Transformers: Dark of the Moon After killing Megatron, Optimus Prine took his blaster and shoot Sentinel Prime who was trying to reason with Optimus on why he sided with the Decepticons.
Ender Wiggin in Ender's Game did this early on, to "win" all future fights with Stilson. It comes up again in Battle School, when Ender is cornered by a gang of older (read: bigger) students who don't care that he's the last, best hope for humanity (in fact, they hate him more because of it.) Ender doesn't find out until years later that the brutal beatdowns he delivered actually killed both Stilson and Bonzo.
What Eragon does to Sloan in the Inheritance Cycle. Murtagh is also found of this tactic, going so far as to behead one of his enemies while the man is on the ground.
In Tamora Pierce's book Lady Knight, a young woman named Peliwin is found by Keladry cutting apart the body of the Scanran solider who "hurt" her, after Kel and her friends raid the camp and rescue the group of refugees Peliwin was being held with. Given the context, it's reasonable to assume that the man raped her. Kel reassures her, telling Peliwin that she can stop now since he can't hurt anyone else ever again.
Later in the same novel, a Naval trooper kicks Caffran while he is down, before bringing his gun to bear. This time, it means that Bragg can get at the trooper before he shoots.
In Ghostmaker, Gilbear, walking the pickett, beats two Ghosts he disapproves of, in an eruption of their regimental rivalries. He kicks one while he's down. When Corbec interrupts, he brings Gilbear down and in Revenge, kicks him.
In Blood Pact, Kolding's Back Story: his father was a doctor during the war, and the Chaos forces broke in to murder him and the wounded. (Kolding saw it; he was sixteen at the time.)
In Terry Pratchett's Discworld novels, Nobby Nobbs is the undisputed master of "putting the boot in" with City Watch prisoners.
Many A Song of Ice and Fire fans feel that young Dark Action Girl Arya will eventually progress into a fullblown Sociopathic Hero. One of the earliest pieces of evidence they point to is the action of viciously kicking the body of one of her father's guards. Earlier in the book the guard had promised her she would be safe because each northman with her father was worth ten southern soldiers. When she finds him dead having killed only a single foe, she commences the kicking and calling him a liar.
Marion Zimmer Bradley's Darkover novel Thendara House. While the Terran woman Magda Lorne is training as a Renunciate, she gets into a sword fight with several men. After one of them realizes that he's outmatched and tries to surrender, Magda continues attacking him and almost kills him. She had gone into a berserk state and didn't realize he was surrendering.
In GK Chesterton's The Ball And the Cross, the two heroes come upon some drunks harassing a car carrying a woman and her driver.
Another of the rowdies rushed forward booing in idiot excitement, fell over the chauffeur, and, either by accident or design, kicked him as he lay. The drunkard got to his feet again; but the chauffeur did not. The man who had kicked kept a kind of half-witted conscience or cowardice, for he stood staring at the senseless body and murmuring words of inconsequent self-justification, making gestures with his hands as if he were arguing with somebody.
In Harry Potter and the Half-Blood Princenote also the film adaptation, Draco Malfoy paralyzes Harry with a petrificus totalus spell and not only kicks him in the face, but actually stomps on his nose and breaks it while he's lying helpless on the ground. Even for the series' Darker and Edgier later books, such crude brutality was quite shocking.
In Jim Butcher's novel Death Masks, Marcone argues for dispatching two unconscious guards. He is not surprised when the Knights of the Cross refuse, and had brought along handcuffs to keep them prisoner.
Admiral Torgis proved he understood as well as Woetjans did that the first rule of brawling is that you always kick your opponent when he's down.
In Alex Bledsoe's Burn Me Deadly, Nicky stops Eddie by saying that if he kills an unarmed and injured man before her, she will see him hang. Eddie doesn't know whether he would actually have killed the man, but he was glad he wouldn't have to find out.
In The Warlock In Spite Of Himself, Tuan indignantly rules out a mildly sneaky move by comparing it to kicking a man in the head when he's down. Rod decides it's not the time to mention he's done that and worse in a fight.
In the Night Huntress books by Jeaniene Frost, "Always kick them when they're down" is one of Bones' rules, and likewise anyone trained by him.
In CS Lewis's Prince Caspian, onlookers are not entirely pleased that Peter steps back to let Miraz rise. Then two of Miraz's treacherous nobles claimed that he had stabbed Miraz in the back, and one of them stops rushing to attack Peter in order to stab him himself.
In The Bible, Simeon and Levi lead an attack on the city of Shechem after the prince of that city rapes their little sister. They tell the Shechemites that they will form an alliance, on the condition that the Shechemite men get circumcised. The Shechemites agree to this, and the men and boys of the city undergo the procedure. Three days later, while they're still incapacitated, Simeon and Levi and their brothers go in and slaughter all the men of the city (and take the women and children as plunder.) Their father, Jacob, gives them a What the Hell, Hero?.
In Gene Stratton Porter's Michael O'Halloran, Mickey recounts how a nurse abused a little girl, one of her charges, and then one of her brothers kicked her when she was down. He did not know any street kid who would kick a little girl when she'd been beat up.
Live Action TV
In the first episode of Firefly, the Fed agent hits Book a few more times after he knocks him out just because. Joss actually said in a commentary that they added this to emphasize just how psychotic the guy was.
On the other hand, Mal taunting and jabbing a fallen Atherton Wing at the end of their duel in "Shindig" is played for laughs (mostly because Athertondeserved it):
Mal: Mercy is the sign of a great man. (stabitty) Guess I'm just a good one. (stabitty) Well, I'm all right...
In the Babylon 5 episode, "The Long, Twilight Struggle," Londo Mollari may be disturbed seeing his ally, Lord Refa, bombard the Narn Homeworld with illegal mass drivers to devastate the planet, but it does not prevent him from carrying out the declarations of the brutal occupation of the planet in council on Babylon 5 with a complete hardass and unyielding. Sheridan was quite willing to continue beating a deserving target long after he'd been knocked to the ground.
In Pushing Daisies, the first episode has Chuck lightly kick the corpse of her murderer. It's more adorable than disturbing.
The concept of overkill is brought up a few times in Criminal Minds: if a killer commits violence against the corpse of their victim, it's considered a sign either that they have a great deal of anger, or they're really starting to lose their mind. Or both.
In one episode, it's considered significant that a murderer has stopped the practice of repeatedly stabbing his victims after they're dead.
In "100" Hotch, in his Unstoppable Rage, kept attacking the Reaper after their intense life-or-death struggle, even though he was clearly already dead. Justified in that it was better to be safe than sorry, and the Reaper had killed Hotch's ex-wife minutes earlier and was threatening to kill his young son next. Morgan had to pull him off while he was still beating the corpse.
In Robin Hood: after the Cat FightKate squeezes Isabella's face and shoves it to one side with a nasty smirk on her face, despite the fact that Isabella's surrounded and incapacitated.
One episode of Drake And Josh has Josh ordering their father to wrestle Drake, who was injured. This is because he discovered his injuries from a dune buggy accident when their parents had forbidden them to drive it.
Leverage: During their fight, Mr. Quinn makes a point of trying to kick Eliot into submission after he's already knocked him down. Eliot quickly turns the tables.
In Samurai Sentai Shinkenger, Manipulative Bastard Akumaru is cut down by Juzo right as the former's centuries-long Xanatos Gambit is about to come to pass, thereby ruining it. As Akumaru falls to the ground, and tries to comprehend how Juzo could be so rotten and evil to the core, another villain whom Akumaru doublecrossed and brutally beat up, Dayu, comes along to give a quick, but smirking "The Reason You Suck" Speech, telling him how foolish he was to trust the human emotions of an inhuman monster like Juzo. She then promptly gives Akumaru a swift, and well-earned kick in the ribs.
In Banshee Lucas, the protagonist, tends to do so as a means of making sure that his opponent stays down and in the future thinks twice about taking Lucas on. In a flashback to Lucas' time in prison we see a sadistic albino inmate do this to Lucas. After beating Lucas in a fight, the albino proceeds to kick, punch and stab Lucas to emphasize that he now "owns" Lucas and can do anything he wants to him for as long as Lucas is an inmate. When Lucas fights the albino again and this time wins, he makes a big show of finishing off the already dying opponent in front of all the inmates so they know that Lucas is someone who cannot be "owned".
In House Of Anubis, Joy was completely heartbroken by Jerome dumping her in front of the entire school during a play and turned to Fabian, her long time best friend, for advice. He instead hurt her even worse, because being a sinner, he had no sympathy for her and instead tore up her self-esteem when it was low to begin with. The other villains tend to do this a lot, too.
Bruce Springsteen's "Born in the USA" contains the line "The first kick I took was when I hit the ground."
Don Henley's "Dirty Laundry" has the refrain: "Kick 'em when they're up, kick 'em when they're down, kick 'em when they're stiff, kick 'em all around,"
During the kayfabe era (pre-mid 1990s), when the staple of a wrestling promotion's television programming was matches pitting top tier and mid-level talent vs. jobbers, a promoter frequently would push a villain as an unstoppable Monster Heel by having him continue to physically punish a jobber well after he had scored a victory over him, often by performing a powerful finishing move on the hapless opponent one or more times. This was always to demonstrate said move's power, establish the heel's credibility as invincible and – the end goal – set up a showdown with the promotion's lead face (seemingly the only one who could withstand the evil man-monster's might). Well-known examples of wrestlers making encore use of their powerful holds/moves after getting the win:
Earthquake (John Tenta) and his running seated senton (the "Earthquake Splash"), sometimes as many as five times after the match was over.
Yokozuna (Rodney Anoa'i, a mammoth-sized Samoan wrestler with a sumo wrestler gimmick) and another form of the senton, this one jumping from the second rope to land in a seated position on his prone opponent's chest. At his peak, Yokozuna would repeatedly "Yokozuna splash" his unfortunate opponent up to four times after the initial win-securing move. (At least once, Yoko continued to sit on the opponent's chest, as an in-ring interview with Mr. Fuji took place.)
Big John Studd, the wrestler who claimed he couldn't be slammed, would often bodyslam his opponents several times after a match. Other times, he would continue to use his submission hold, an over-the-shoulder backbreaker, until the jobber passed out from the pain.
Sid Justice's finishing move was a powerbomb, where the opponent is hoisted into the air and slammed onto his back. During his pre-Wrestle Mania VIII run as a heel, Justice used the move up to three times on his foes post-match.
Far smaller than the above opponents, but Greg "The Hammer" Valentine was often fond of re-applying his submission hold, the figure-four leglock, on a defeated jobber; the formula was that he would release the hold to accept the victory, then — usually to push him as sadistic — push the referee aside, grab the writhing-in-pain jobber's leg, and put him in another figure-four leglock (obstensibly to "break the leg").
For a time in the late 1980s, Valentine wore a steel brace over his knee, claiming it was to help heal a knee injury, but the intent became clear once he began applying his figure-four leglock and jobbers were in even more pain. This included during and post-match punishment.
Baron Von Raschke was a Greco-Roman specialist, but was more fond of using his brain claw to force his beaten opponents into a painful submission. At times, he was even more fond of keeping the pressure applied until he drew blood.
Demolition (Bill Eadie and Barry Darsow as the KISS-influenced Ax and Smash, respectively) would do their "Demolition decapitation" finisher — Ax drops an elbow from the second rope, while Smash holds the unconscious opponent over his knees — on occasion. The most famous example was to jobber Brady Boone, whom Vince Mc Mahon happened to point out was the "cousin" of Billy Jack Haynes (a mid-carder that the WWF was trying to push as part of a tag team with Ken Patera). In the Boone example, Haynes came out for the save ... only to be on the receiving end of a beatdown and at least two Demolition decapitations; Patera then came out to stop the assault, but he too got it!
More often than not, several of the above examples would sometimes feature the jobber being carried from the ring on a stretcher (and sometimes for added effect, "blood" would be added to simulate internal bleeding), in a further attempt by the promotion to demonstrate the power and sheer evil/unstoppability of the monster heel. Carrying the trope even further, sometimes the heel wrestler would, after watching the medics tend to the "injured" jobber, grab the wrestler as he's being taken to backstage (for "medical attention") and deliver the powerful finishing move again in the entrance aisle — and more than once, the heel wouldn't stop with just one at this point.
Occasionally, this trope would be reversed, with the face punishing a heel wrestler — especially if he were the Monster Heel that sadistically sidelined the rest of the hapless jobbers and terrorized the faces — to both give the heel his comeuppance and send the audience home happy. In 1981, then-beloved babyface Andre The Giant continued to punish an obviously beaten Killer Khan in retaliation for breaking his leg; three years later, he spent 15 minutes torturing hated villain The Iron Sheik, and had him beat long before he finally decided to pin the bloodied, battered and bruised Iranian. During his first WWF Heavyweight Championship run, Hulk Hogan was known to continue punishing such vile villains as "Dr. D" David Schultz, the Iron Sheik, "Mr. Wonderful" Paul Orndorff and Randy Savage, long after he could have easily pinned them.
The "stretcher match" is Exactly What It Says on the Tin – an opportunity to continue beating your opponent into a comatose state, long after victory would have been assured, to force him to be carried out on a stretcher. The most famous was the Andre the Giant vs. Killer Khan stretcher match in 1981 in Philadelphia.
Alberto Del Rio has a habit of assaulting people whom he's just beaten or have had a grueling match with someone else, ramming their shoulders into the ringpost or barricade, then putting them in his Rolling Armbar over and over again.
Similar to Alberto Del Rio, Mark Henry, as a Heel, and especially during 2011, often assaults people. He'll ram them into things, hit them with his World's Strongest Slam and Running Splash over and over again, then wrap a steel chair around their leg and jump on it.
At No Mercy 2004, Billy Kidman defeats Paul London with a Shooting Star Press, causing London to cough up blood. Paramedics load London on a stretcher and attempt to cart him away... when Kidman shoves them away and gives him another Shooting Star Press.
In a 2005 no disqualification match pitting Triple H against television commentator Jim Ross, Triple H — at the height of his monster heel run — bloodied Ross and attempted to pin him. Taking advantage of another "rule" where the only way to win was by pinfall, Triple H repeatedly pulled Ross up at the two count to continue the punishment ... that is, until Batista arrived to knock out Triple H and help Ross get the win.
The flavor text of the Magic: The Gathering card Whipkeeper reads, "If you don't hit your adversaries while they're down, they might get up again.'' In terms of game mechanics, certain Magic cards like Memory Lapse/Lapse of Certainty, which put an attempted spell back on top of the opponent's library, work best as kick 'em while they're down cards; if someone doesn't get enough land cards to cast anything and they finally DO get something they can cast, these spells don't let them play anything that turn, and ensure they get no land next turn.
There's a set of gear in the fourth edition of Dungeons & Dragons that gives a + 5 Damage bonus to those who've been knocked prone when the set is complete.
Also, the coup de grace. A full-round action that can only be done to utterly helpless opponents (not just knocked down or pinned, but completely immobilized or unconscious) which is an automatic critical and forces the target to pass a high-level fortitude save or die immediately.
Champions — The recovery mechanics of the hero system are such that an enemy that is knocked just a few points into unconsciousness can get up and continue fighting in just one or two actions, assuming the GM doesn't just declare them "out. So if you just barely knock out a big threat after a long fight it is essential to hit him again so the rules for really unconscious characters kick in.
GURPS's Martial Arts supplement features a Stamp Kick maneuver.
The Battle Tech rules practically invite this — kicking a prone adjacent BattleMech with another is basically free all-but-guaranteed extra damage, and is often the only physical (as opposed to weapons) attack you can make against them by the game rules anyway. Of course, since we're talking about Humongous Mecha here, the emotional impact may not be quite the same.
In Civilization IV this is one of the default responses if you demand (and successfully get) tribute from a weak player or vassal state.
Neverwinter Nights In the first module of the Bastard of Kosigan modules, a small kid takes the opportunity to beat up the dead body of his abusive boss after you kill him. Your reaction (either gently discouraging him or handing him a knife so he can have more fun) nets you alignment points.
In Mega Man XMaverick Hunter X, Vile repeatedly stomps on X's seemingly unconscious head and kicks him around the room after their battle during a cutscene. You only see that during Vile Mode playthrough.
Vile's intro stage also features this. After you beat X, Vile spends some time shooting X around with his Shoulder Cannon.
In Bushido Blade, attacking a downed opponent is one of the acts forbidden by Bushido that damages your invisible Karma Meter.
This is actively encouraged in some games of the Tales Series for the purpose of lengthening combos. Some artes specifically have the property of being able to hit knocked down targets, while others force them to stand up so they can't benefit from the Mercy Invincibility they get after remaining there for a brief moment, while others go even further and ignore aforementioned invincibility.
Senel from Tales Of Legendia has no qualms about grabbing downed enemies and slamming them into the dirt again (Repeatedly, in the case of certain monsters like dragons). These throws are his most powerful attacks, but allow the enemy to stand up after they connect.
An enemy that's especially fond of doing this in Tales Of Vesperia is the Griffin with its Infinity Beak attack, which as the name implies, will keep hitting a downed party member until they're dead or someone interrupts the attack. There's also Yeager, who will end his combos with a pointblank shot from his rifle if his target gets knocked down near him.
Max Payne 2 features Big Bad Vladimir Lem kicking Max in the ribs after losing his gun. Max recovers as the Big Bad leaves, revealing that he took the kick primarily to hide the lost gun: it was under his chest.
In Max Payne 3 enemies will attack Max while he's sprawled on the ground. You can return the favour on downed enemies and have no reason not to.
The beginning of Half-Life: Episode Two introduces the Hunter, a gorilla sized synthetic enemy who delivers a Game Breaking Stabbing to Alyx Vance. And then when she's down and gasping for help, it stomps on her hard enough to put her in a near-fatal coma.
In the Battlefield series, the AI bots in single-player have no qualms about charging in and killing a medic and the wounded soldier he's treating. Particularly pronounced in the Project Reality mod, where soldiers take several moments to be restored to full health after being revived.
Valkyrie Profile Covenant Of The Plume - Part of your pact with single-L Hel is to rack up "sin," and the main way to do it is to do keep smacking foes after they've already taken enough damage to die. Each level has a set amount of sin that must be accumulated, and hitting that amount gets you a small reward. Hitting 150% or 200% of the amount gets a much larger reward and a message that you have greatly pleased Hel—it's up to you whether to be ashamed. On the other hand, repeatedly failing to hit that amount results in your fighting a Doppelgänger with much better stats than you, and if you want any hope of beating it you'll probably have to use the other method of acquiring sin and sacrifice the life of one of your allies for a tactical advantage. Pretty much played straight, since the protagonist's a Byronic Hero at best.
A key technique in many 3d Fighting Games. The term 'okizeme' is at times used to describe what to do to the grounded guy; 'wakeup options' are what to do when the grounded guy tries to get up. Options run from a simple kick to low blows to tossing them downrange.
Similarly, games that allow this also have a fun way of dealing with an opponent after you win the round ...
Professional Wrestling games often fall under Fighting Games, and have this as well. Naturally, you do have to get down and either pin him or bend him in ways God didn't intend when the human body was designed.
In Assassins Creed II you can kick downed enemies when using fists, or attack them in a more lethal fashion with other weapons.
This is a common technique in Dragon Age, to a point that the AI is actually designed to prioritize grounded targets to make use of their momentary vulnerability.
The Dark-typePokémon move "Assurance" works something like this—it does more damage if the opponent had already suffered damage on the turn the move was used.
In Bungie's Oni, Konoko has no problem doing this to fallen foes — and they have no problem doing it to her either.
Scarface: The World is Yours. One mission requires Tony to steal cassette tapes but not kill the owner. After doing so, he returns -twice- to wildly kick the downed and dazed enemy. In 'return', failing the 'hassle the cops' mission sees them give Tony a wild beat-down. Of course, success sees the cops plunge into the ocean. Really well done success sees most of them explode.
Several attacks in Hybrid Heaven only work on prone opponents, and one of the best is a simple kick to the head. Like most moves in the game, almost all of these are learned when an enemy uses them on the player character.
Dawn Of War: Units will continue to shoot at knocked-down units in range, but will engage in melee if specifically ordered to attack a downed target. Given the Crippling Overspecialization of most shooting units, this can quickly end in disaster.
In Dark Messiah, finishing move deals massive damage against a prone opponent. Expect to use it a lot whenever there's no conveniently placed spikes around.
Defeat a prefect in Bully, especially when no others are around to nab you (what with your Wanted Meter being quite full for defeating a prefect). It's very hard to not put the boot in afterward. Also fun for other targets, too!
The World Ends With You has it in the first day of the third week where Neku is left to face the Noise alone. Beat, who is a Reaper, can't take that kind of event so he turns back to a Player and makes a pact with him.
Most of the party members and some monsters in Star Ocean The Last Hope have attacks that are able to do this (In the case of Edge, he literally kicks them). They can be spammed to create what would be an infinite combo if not for the target's ability to eventually activate Rush mode and become Immune To Flinching after getting hit enough times.
Slurpers in Silent Hill 3 knock Heather down, attack her while she's down, then possibly knock her down again when she gets back up; a potential Cycle of Hurting.
Silent Hill in general lets you kick an enemy while it's down as a finishing attack of sort, since the fallen but not quite dead monster may get back up again unless you truly drain all its health.
Possible in Samurai Warriors, surprisingly enough. Every characters jumping charge attack involves slamming the ground in one way or another, and some don't even need to jump to hurt someone who's lying down. Musou attacks also end with the character releasing an aura, hitting everyone immediately around them, standing or not.
As it includes SW characters, Warriors Orochi also allows you to do this (though not all Dynasty Warriors characters always have such an attack as easily usable as SW characters. Some don't even have one that can hit enemies lying on the ground).
As par for the pragmatic course it's a very viable move to peform a crouching medium/kick attack on a downed opponent in BlazBlue since this is likely to result in them getting lifted off the ground, setting them up for (yet another) combo. In fact, a few characters have moves exclusively meant for usage against downed opponents. E.g., Ragna pulls them up to their feet and socks them in the gut, Noel shoots the downed opponent and Tager magnetizes them and drags them up to their feet with one finger.
Hazama / TerumiYuuki gets an all new super in Chronophantasma that is basically just him exemplifying this trope by stomping the opponent in the head many and several times repeatedly before kicking them away. When performed in his Overdrive form he adds insult to some additional injury (caused by increasing the number of stomps) by leaning down, grinding his heel against the opponent's face and mocking them before finishing the combo.
In Ready 2 Rumble Boxing: Round 2, you can continue to hit your opponent several times even after you've knocked them down, due to their lengthy "falling down" animation. You can even do this when you activate "RUMBLE" Power, which lets you give harsh beatdowns such as this. Also, while you're doing this, you can actually get more RUMBLE power by taunting or using heavy attacks.
In Sleeping Dogs, this is one of the more mundane things Wei can do to a downed opponent. The other things include slamming the hapless fool's head to a nearby steel railings or just plain shooting them. If you're really into revenge, you can run their head over with an armored car. Squee!
Many characters in Injustice Gods Among Us do this for their victory pose. The Flash lifts his defeated opponent up with a whirlwind and uppercuts them off screen, Ares skewers the loser with a flurry of swords, Black Adam puts a foot on their chest and electrocutes them, the Joker douses them in gasoline and tosses a lit match on them, and Harley Quinn literally kicks them while they're down.
In Shin Megami Tensei Persona, All Out Attack functions like this. A viable tactic for both the player characters and the monsters they fight, when all opposing units are weakened by hitting their elemental weakness or ailing them with status effects, the entire party can gang-up an extra Almighty-elemental hit on the downed opponents without a mean to defend against.
During the first battle against Xykon, after Durkon uses Thor's Might to take out a bunch of goblins that Belkar had just been gearing up to attack, Belkar proceeds to stab one of them in the face even though they're already dead. Well... yes, he is evil.
Later, he kicks Miko after Roy knocked her unconscious. She's probably very lucky for the Mark of Justice.
Belkar also does a verbal version of this to Hinjo, calling it an "insult of opportunity".
Belkar also desecrates the dead, by giving a slaver a shot of his 'marinade' and making good on his threat at the beginning of the strip. Technically the slaver was still alive, just beheaded and in the process of dying. Note the lack of Xs in his eyes.
Bittersweet Candy Bowl had Confrontation: if Lucy hadn't stalled him, Alejandro would have crushed Mike's skull while down. Later, after they win the fight, they instead turn it on the bully.
In thisGirl Genius, Violetta expresses her fury by kicking the wounded Tarvek — who is not actually down, but can't really fight back because they are on the same side.
In "Ayla and the Birthday Brawl" of the Whateley Universe, Phase is down and injured. Matterhorn has a mage put a paralyzing spell on Phase so Phase cannot move or use any of her powers. Matterhorn then uses his powers to grow to twenty feet tall before stomping on Phase's knee and arm.
In The Simpsons, Homer's new Jerk Ass neighbor tried to hit Ned, who swiftly incapacitated him leaving him on his knees begging him to let go (Ned was bending his wrist back). Homer than smashes a chair into him leading to this exchange:
Neighbor: Why would you do that? I was begging for mercy.
Homer: I saw my advantage and I took it. That's what heroes do. (complete with Horatio Caine style hero pose).
Starscream does this to Megatron after the latter's battle with Optimus Prime in Transformers The Movie. There was a fan theory (confirmed in the IDW comics) that he does this to Megatron in the Live Action one too, getting in a last shot at him along with the earth forces jets before running away. Well he is The Starscream.
In an episode of Garfield And Friends, a neighbour is so riled up by Garfield continuously stealing food from him, he beats Jon to a pulp, and is ready to keep it up even after Jon's heaped up on the ground, however Garfield manages to scare him away.
Neighbour: Now I'm really gonna let you have it!
Jon:*haggard* That wasn't it?
Another rare heroic example in occasional episodes of The Dreamstone. While usually pacifistic, the Urpneys trying to take away the Noops' good dreams seemed to be hit a big Berserk Button and even after protecting the stone they would sometimes decide they needed to be "taught a lesson" ("Blob's Incredible Plan" dedicates almost half the episode to kicking the Urpneys after they had already outsmarted them). Subverted at least once, when Amberley calls off an angry Rufus since they already got back the stone.
Buttercup was lectured by her sisters for this in an episode of The Powerpuff Girls, giving Fuzzy Lumpkins a No-Holds-Barred Beatdown despite him surrendering. The doctor tending to him even more or less labels her a monster.
At one point in a supposedly friendly soccer match between L.A. and Sydney, a player was on the ground, an opponent stepped on his outstretched arm, noticed, and continued, temporarily putting all his weight on the poor guy's arm. Wearing spiked soccer boots. Ouch.
Overkill is a criminalistic term to describe actions of murderers that would have been lethal to the victim if it hasn't been dead already. E.g. when someone is killed with a knife and there are 100+ stab wounds found on him, clearly many of them were post-mortem. The term "Overkilling" is usually tied to serial killers, because they tend to follow their own ritual when committing a murder and the ritual most often doesn't end with the victim's death. Overkill can be presented as evidence of premeditation in a murder case, seeing as someone usually doesn't shoot a person 15 times without really meaning to. Such evidence can also be used as an aggravating circumstance at sentencing, permitting the prosecutor to ask for a harsher sentence than usual.
Attacking someone on the ground automatically voids any claim of self-defense in most jurisdictions, for obvious reasons.
Historical European grappling manuals rarely included ground-level techniques, because when you've successfully thrown the opponent to the ground, you could presumably just kick the snot out of them.
In Mixed Martial Arts, kicking a downed opponent is legal in the Unified Rules of MMA as long as you do not stomp and the kick is not to the head (or any area that is also illegal on the feet). PRIDE rules, however, allow kicks to to the head of downed opponents, which are called "soccer kicks" and can be pretty dangerous.
To paraphrase a hunter's safety guide, a good hunter knows it is morally wrong to shoot a sitting duck. It is however acceptable to shoot a flying duck, because a small bird is an equal match for a hunter with a rifle.
This trope happened in a metaphorical sense when the Argentinian government nationalized a Spaniard oil company, taking advantage of the economic crisis in Spain, and the fact neither Spain nor the E.U. aren't able right now to fight back against the Argentinians.
Concentration camp Kommandant Amon Göth notoriously devised all manner of nightmarish miseries for his prisoners.
Austerity measures. The people is wallowing in misery due to failing banks dragging everything with down with them. So what is a democratic government to do? Why, use taxpayers' money to bail out the bank of course, and destroying the welfare state whilst demonising the people who use it as "lazy scroungers" (how ironic from the government of all people) to keep the country running!