In Season 10, Agent Maine vs the Strong Insurrectionist, Round 2. It's over in ten seconds. Strong Guy throws a punch, Maine catches it, effortlessly twists the arm back, then punches him so hard that the guy is decapitated!
Despite the initial scare (literal Legions of Hell invading earth? Game over man, game over!), the demons from The Salvation War are total pushovers (due mainly to the demons still relying on Bronze-Age weapons and tech against the humans' modern technology) and massacred with barely the most token of resistance...that is, until Satan is forced to rely on Belial and his ragtag band of pariahs for outside-the-box retaliation. The angels, on the other hand... well, one of them manages to destroy a Russian jet by yelling at it.
The war against the demons was actually nicknamed the "Curb-Stomp War" in-universe.
To be fair, the army revealed that if the war with Hell went on a little longer, humans would have faced some big troubles. Oh, not from the demons — the humans were running out of ammo.
This would have more long-term consequences, since at least in Western countries it led to pity and even sympathy for demons that affected human relations with them post-war (and, it seems, influenced human harshness against the angels in return).
Just to give you an idea of how badly the demons were destroyed, in the first battle the demons were fielding around 440,000 troops, and were facing several thousands of humans. The humans suffered 600 casualties. Only 300 demons lived.
The That Guy with the Glasses 1st anniversary video included a few of these. Most notably The Nostalgia Critic, despite effortlessly dispatching anybody else he runs into and having fought a pretty close battle with The Angry Video Game Nerd previously, seems to get beat up pretty badly whenever he runs into the Nerd in the battle. This includes taking multiple attacks to the crotch. Even so, the battle technically ends in a tie and the Critic does gain the upper hand on a few occasions. Also, nearly every character is introduced by literally appearing out of nowhere and knocking the previous character to the ground. Nearly all of Angry Joe's scenes consist of him screaming and doing crazy karate gestures before being knocked out by another character seconds later. And Ma-Titakes a particularly large amount of punishment from just about everybody.
Just after Linkara manages to defeat Mechakara, he winds up on the receiving end of one at the hands of Lord Vyce.
"The Turks or the Geek" in the Whateley Universe. Team Kimba finally figures out who bushwhacked and stomped their least battle-worthy members a month or so earlier. They challenge said team (the Young Turks) to an arena match in front of them whole school, with only the four team members considered the least threatening. Team Kimba uses their abilities to learn how the Young Turks plan to game the fight: extreme curb stomping ensues.
In the Global Guardians PBEM Universe, the Blades (a trio of superhuman assassins) were hired to take out the members of the titular team. Understatement to say that the Blades were out of their league...]]
Scimitar: "Die, American!"
(slashes his weapon at Ultra-Man, who doesn't even attempt to avoid the strike; the blade shatters on Ultra-Man's invulnerable skin).
Ultra-Man: "Did you bring another one of those? I can wait until you go get it..."
Whenever Mario fights anyone in the Bowser's Kingdom series, he usually comes out on top.
The most recent Death Battle between Rainbow Dash of My Little Pony Friendshipis Magic and Starscream from Transformers Generation One has Rainbow Dash pulling one of these on Starscream, to the point that the battle was the most one sided battle they've ever done by farnote Starscream only manages to even connect with an attack once, via a cheap shot with the Null Ray. Given that she's not mechanical, this does little more than annoy her. He also manages an annoyed swat which accomplishes even less, but it's questionable whether that one even qualifies as an attack.. The fact that this trope was used at all is unique for the series as usually the battles are shown to be as close as possible, even if the winner needs to receive a nerf or the loser a buff to even things out a little.
The best part is that this is completely justified by their given stats and abilities taken from each of their respective series.
To be fair, it was more balanced than you might think. Dash only takes two hits over the course of the battle, one from Starscream's massive hand (but she has been known to smash into cliffs with no injury, so she can easily survive that) and one from his Null Ray which has no effect on living beings. But when you think about it, had she been hit by any other part of his arsenal (his gun, or his missiles) it would have been the end of her on the spot.
And it helped Rainbow Dash that G1 Starscream's life is a never-ending spiral of failure and misery, being the universe's own Butt Monkey as a result of his own actions.
Another case was in the Teenage Mutant Ninja Turtles one, where Leonardo attacks Michelangelo and kills him in seconds. It was noted in the aftermath that Leonardo went after Michelangelo because he was the easiest target.
Metal Sonic is a match for every one of Wily's Robot Masters combined. A Power-Up or two is all he needs to kill nearly all of them. And then Wily has the bright idea of using his Roboenza virus to defeat him, which turns robots into violent traitorous killing machines. Metal Sonic destroys and absorbs Eggman's entire Egg Fleet, transforms into Metal Overlord, and kills everybody left on the field - Bass, Eggman, Wily; everyone - along with the entire city, and possibly the world.
In Worm, Weaver and the Chicago Wards get singlehandedly demolished by Contessa in her first appearance.
In Noob, Omega Zell once decided that he would prove himself worthy of the Justice guild by beating Saphir in battle. Saphir killed him with an energy projectile before he could even pull his sword out.
Most of the battles in Vaguely Recalling JoJo are cut in length. The Fight with Forever the orangutan ends as fast as it begun. Jotaro finds that Forever is suspicious and pummels him into oblivion.
After kidnapping Donnie and destroying the present they made for him, Tom Collins in Demo Reel gets a well-justified beatdown from a very angry Rebecca. All he can do is cower, pull a gun on her and call her a bitch.
In an episode of Maricraft, Mari and Lasercorn were at war in their game of Minecraft after Lasercorn massacred a village so he could conquer it as "Lasercornia", and when Mari objected to this, Lasercorn declared war on her for "insubordination". When Jovenshire entered the game and claimed to be a neutral party, Lasercorn decided to kill Joven and steal his stuff. Bad idea. Joven, who had previously been playing in Creative Mode, was clad in full Diamond Armor and wielded a Diamond Sword. Lasercorn got in one or two attacks, producing Scratch Damage, before Joven annihilated him. This also convinced Joven to ally with Mari. Lasercorn spent the rest of the episode in permanent Oh Crap mode.