Who could forget that moment in 52 when Black Adamkilled death? (To be fair, it was really a genetic-plague science experiment created by a cult, but still.) Dr. Cale probably summed it up best:
Dr. Cale: Black Adam killed Death, the pale horseman! What does that make him?
When Judge Dredd is confronted by the incarnation of Fear itself, the latter attempts to use his Nightmare Face that causes instant death to any mortal on him. Except Joe drokkin' Dredd is no mere mortal. Gaze into the fist of Dredd!
In a one-off story of dubious canonicity, Satan comes to Mega-City One to try and tempt Dredd. Dredd responds by not only refusing his offer, but by beating up Satan, arresting him for the crime of instigating every other crime, and locking him in iso-block 666.
The Grievous Journey of Ichabod Azrael: Ichabod Azrael kills several demons, angels, and other supernatural entities despite being a mere mortal. This is because he was secretly given his powers in the afterlife by Charon, The Ferryman.
Aquaman apparently makes it an annual tradition to stomp Cthulhu (in the form of the Brand X 'Night gods') a new mudhole with an assist from Etrigan. Interestingly, the one unfortunate witness who had to see all this- unknowable terrors from beyond, Hell-born demon, and all- was most frightened by Aquaman.
Atomic Robo Volume 3 has Robo facing down an Eldritch Abomination from outside the universe multiple times across the 20th century, with the help of cars, lightning guns, and Carl Sagan. Existing outside space and time, it keeps coming back, but ultimately all the Robos from each Cthulhu encounter team up for a cross-time beatdown.
And more or less literally in the first four pages of The Authority: Prime, a miniseries of, admittedly, debatable quality.
Hawksmoor: What the hell is that thing? Doctor: Your basic elder god, returned from a dimension it was banished to millennia ago, here to turn Earth into its own personal slaughterhouse. Hawksmoor: So we're talking... Doctor: Two minutes.
Batman: Batman does this to Metron, one of the New Gods. He tells Metron that he knows more than him because of his human form. Metron shapeshifts to a Human and says "What's so special about THIS?". Batman punches him. Pow!
Of course there was also the time when Batman — Bruce Wayne had just returned from the dead and approached then-current Batgirl and ex-Robin Stephanie Brown. The Bitchslap she gave him was extremely enjoyable and totally deserved — and Batman is a God in his own rights.....
Batman vs. The Incredible Hulk: Batman has, in one of the earliest inter-company Marvel/DC crossovers, taken down the Hulk. That's right, Batman once brought down the Hulk!
Batwoman petrified Medusa and then literally punched her out by shattering her resulting stone form with her fist.
Beta Ray Bill has smacked Galactus around quite a bit as well, and actually sets out to kill him in the Godhunter miniseries.
In Blackest Night, Heat Wave (who's just a guy with a really good flamethrower) manages to pump out enough fire to melt Black Lantern Rainbow Raider's power ring, destroying him. This is notable because power rings are normally indestructible. Heat Wave quips, "Everything has a melting point."
The Black Panther punched out Mephisto once. With his bare hands. However, it turns out he was backed up by Applied Phlebotinum (as is often the case with these situations.)
There was that time Captain America kicked the Devil's ass, actually defeating the Lord of Darkness in a straight fight. The proof is here.
Captain Atom beat up Nekron, one of three Anthropomorphic Personifications of death itself. Of course, the whole reason Nekron is fighting him in the first place is that Captain Atom's power comes from the life energy of the universe. (So when Cap later beats up another personification of death, the Black Racer, it's a little anticlimactic, frankly.)
Earth-1 Supergirl lays an absolute beatdown on the Anti-Monitor before being taken out by a lucky shot... and as he limps off the battlefield, the Anti-Monitor says she nearly killed him. That's right, she nearly killed a being who ate universes.
Earth-2 Superman completely beats the Anti-Monitor in the finale by punching the flaming, shrieking, enraged head that's left of him.
Played for comedy in Damage Control when Edifice Rex (a cosmically-powered crewman) decides to use his powers to reverse the Big Bang and force everything back into the cosmic egg. While an assortment of cosmic beings consider how to stop this, his boss simply fires him.
In The Dark Tower: The Long Road Home, Sheemie manages to knock down the Crimson King, who is — for all intents and purposes — the universal personification of evil in every single conceivable form of existence.
Both the DC Universe and the Marvel Universe have plenty of Gods, ultimate evils, and universe-destroying Eldritch Abominations (one of them even became a playable character in a video game!) including some that are nigh-omnipotent, eat planets on an almost-daily basis, and greatly outclass the local superheroes. However, said abominations have the misfortune of ending up inidealistic superhero comics. This is sometimes justified in-universe by having rival gods, cosmic entities, artifacts of great power, etc. so that said abominations never have an absolute chance to destroy the universe.
DC Comics Presents #24 sees Deadman, a dead acrobat, get into a fistfight with the Grim Reaper and win.
Every superhero in the DC Universe has punched out the Evil New GodDarkseid, the ruler of Apokolips including nonpowered Badass Normals such as Batman and Green Arrow. This probably explains why Darkseid hates Earth and its heroes, given that his superiority complex makes him believe that he should be able to beat them. He also hates Superman with particularly obsessive hatred, possibly because Superman, whose personality is the exact opposite of Darkseid's beliefs in every possible way, manages to humiliate him again and again.
Darkseid isn't quite in the Cosmic Horror Story category though, and it is often hinted at that Darkseid isn't really trying or isn't at full power when he is fighting the Superheroes. When you consider the ease in which he takes over the world in Final Crisis, this gives those old theories some credence.
Or just says something about the Anti-Life Equation, which he's been searching for at least 30 years of comic continuity. He was easily defeated time and again without this weapon, and takes over the world in a fingersnap once he has it. Guess that's why he wanted it so bad. Edit: He's never been beaten without plot devices or extenuating circumstances. And most of his past defeats were shown to be avatars. Not to mention the revelation of the New Gods and how much boom tubes scale them down. Or that they represent abstract concepts. Now Darkseid's death in Final Crisis? That's punching out Cthulhu.
Darkseid has a history of keeping worthy opponents alive if they've put up a good fight. This isn't Bond Villain Stupidity as it sounds, considering his "defeats" tend to be more that the opposition's just capable enough that the current plan's no longer worth the effort, and Darkseid has had no few occasions where he converts heroes into his footsoldiers. The trouble of when he brainwashedSupergirl and when his underlings tried to use Batman as a soldier template can attest to that.
Doctor Strange: Fighting eldritch abominations is Strange's job. Demon lords, dimensional overlords, cosmic monsters... he stomps one almost every issue.
Dungeon Twilight: Herbert One-Hit Kill Absolute Evil thanks to his skin turning green making him vulnerable to Herbert's Finger Poke of Doom. Soldiers all around renew allegiance to him after seeing him kill the gargantuan beast in such fashion. His son Elyacin was on his way to do it with strength alone.
Special mention for The Coming of Galactus, by Stan Lee and Jack Kirby. It was basically the first time this trope came into play in superhero comics. Nowadays, Galactus is a standard character, we have seen him defeated or humbled several times, we have seen characters even more powerful than him many times, we have seen superheroes fighting hopelessly against such ultimate forces basically once a year or more, we are used to them coming on top of all that as if it was nothing... but by then, when Lee and Kirby wrote that story, nothing of that applied. The Fantastic Four were facing a foe of such power that was completely beyond anything else ever seen before in either Marvel or DC.
Allegedly, the inspiration for Galactus comes from Lee and Kirby brainstorming what to do for the 50th issue, when Lee asked "What if they fight God?"
Reed Richards killed the Dreaming Celestial, one of Marvel's closest equivalent to Creator Gods, trying to destroy the universe, combining this with Did You Just Flip Off Cthulhu?.
The Fantastic Four's penchant for this trope has gotten so impressive that their reputation precedes them:
Sue: (after an army of aliens suddenly hightail it for the horizon) What was all that about? Reed: It turns out they speak trinary code, so I said "I am Reed Richards of the Fantastic Four..." Sue: Go on? Reed: Actually that's as far as I got. It was enough to send them running.
Let us not forget the time that one of the The Flash Rogues (Who are considered useless in their own right) called "The Trickster" (a former aerialist with no superpowers, and who uses rubber chickens and yo-yo's to fight) tricked Neron (AKA Satan) into letting him out of hell.
In Freddy vs. Jason vs. Ash, Ash Williams rams his car into Freddy Krueger — who by now had god-like powers—and shoots him in the nuts!
One of the Ghost Riders has an ability called Penance Stare, which forces people to experience the suffering they have wrought on others. In Fantastic Four: The Animated Series, he uses this power against Galactus. This trope applies to every time that Galactus has the misfortune of ending up in a Super Hero comic, so you know he's going to lose anyway, but this example may take the cake. Later Riders also gained this power. But in this instance, the Rider was merged with a kid named Danny Ketch, and was a half-angel, half Demon who was actually the Angel of Death at the time of this show. He was originally human and named Noble Kale. Head exploding at the strangeness of this character's plot probably ensued on a massive scale when this all came out.
Heck, he's even fought Lucifer (not Mephisto, Lucifer) and won.
The Noble Kale version of Ghost Rider also killed Blackheart, the son of Mephisto. Given how Mephisto and Satan have been swapped around as though they were the same guy in Marvel for decades, this basically means we should be asking Did You Just Kill Cthulhu? Or more accurately, did you just slaughter the ANTI-CHRIST?
In Uncanny Avengers Annual 1# Johnny Blaze runs fowl of the heroes and gets into a fight with Physical God Thor, GR proceeds to kick the God of Thunder's ass and knocks him out in front of the rest of the Avengers.
Ghost Rider: The Might of a God pales before the true strength of a Demon.
Cosmic Ghost Rider not only beats the crap out of Thanos, but outright destroys him with Penance Stare. Given this version of Ghost Rider had the power to make mincemeat of Marvel's collective heroes, maybe it isn't that shocking.
On the flipside The Fallen Silver Surfer manages to kill Cosmic Ghost Rider with Mjölnir and when Cosmic GR "fights" Hela of Godesss of Death, she owns him without lifting a finger.
The Goon and Hellboy are both pretty much based on this trope. In the latter, while many of the supporting characters often use more traditional methods of dealing with monsters, the main character's usual approach is to punch them really hard with his giant stone hand and shoot them with his Hand Cannon. This is Lampshaded in the Goon/Hellboy crossover issue found in the Heaps of Ruination trade paperback. When confronted with the Communist Airborne Mollusk Militia, and specifically their champion, a massive octopus with a hot-air balloon strapped to his head, this bit of dialogue ensues:
Hellboy: Stand back! I do this for a living!" Goon: Oh yeah? When I come across somethin' like this I just try ta punch it in the head — what do you do?" Hellboy: Pretty much the same thing. The two heavyset heroes go on to do just that.
In Green Arrow, back while Hal Jordan was the Spectre, Oliver met his friend after coming back from the dead. He was stunned and Hal shrunk to normal size to approach him. That's when Green Arrow punched Spectre.
Grimjack killed a god in his first storyline. Admittedly, it was somewhat depowered, but still...
Heroes Reborn (2021) has the Squadron Supreme of America do this regularly, starting with Hyperion killing Galactus with a single punch and after a short break he kills the Hulk so many times that the Hulk's body just quit and was reduced to a radioactive soup.
The Incredible Hulk: The Hulk often invokes this trope, whether he's smacking around Thor and Hercules, or smashing some multiversal threat with the Defenders.
In the 1970s, veteran scribes Marv Wolfman and Len Wein wrote The Incredible Hulk: Stalker From the Stars, wherein the Hulk crosses paths with an Eldritch Abomination attempting to escape its prison beneath the Earth so it could conquer and enslave humanity. In this case, the Hulk doesn't punch Cthulhu out so much as rip him to pieces and burn him alive. Ouch.
One early foe of his was the Galaxy Master, whose most common form was a huge gaping maw hanging in the middle of space and destroys planets to consume them as food. Hulk's answer? Jump inside it and smash it from within.
Then there is the time he blew out the mystical flames composing Dormammu's head by smacking his palms together. Dormammu wasn't out for the 10-count though.
He also on one occasion nearly cancelled out the power of the Order-Half of the In-Betweener, who can give Galactus a fight.
Other feats include the Hulk handling the infinite power from the singularity of the core of a black hole and ripping apart a weapon designed to withstand and kill the Celestials.
Onslaught was a powerful fusion of Professor X and Magneto's conscious into a Psychic Entity who had the power of other Omega-Level mutants such as Franklin Richards and Nate Gray and could create a sun from nothing. An Invincible Villain for Marvel's heroes... until Jean Grey removed Bruce Banner's conscious from Hulk - que one very, very, very angry Megaton Punch and Onslaught's physical form is destroyed. Unfortunatly, this also had the side effect of opening a dimensional rift.
During World War Hulk, he also managed to beat Zom, arguably the most powerful known demon in the Marvel Universe, although later issues somewhat retconned this by stating that Doctor Strange was holding it back.
In one Hulk book, Red Hulk punched The Watcher, then went on to punch an Elder of the Universe to death. Justified in that Red Hulk's energy-absorbing powers basically mean that the stronger his opponent is, the stronger he is.
In the Immortal Hulk, the Jolly Green Giant is up against The One Below All the exact opposite of The Above All aka God basically an Eldritch Abomination so powerful even Mephisto (who’s fought Galactus) is scared of it. But after a Heroic Second Wind Hulk does a Shockwave Clap that literally blows the One Below All away. Hulk admits afterward he only bought them a minute breathing room to escape the Lovecraftian nightmare, but that doesn't make it any less awesome. Made even more awesome retrospective with the revelation that One Below All is really the Superpowered Evil Side of the One Above All, but Hulk still clapped him anyway. Justified though since Hulk is apparently the child of One Above All and the counterbalance to creation by being a force of destruction itself.
Speaking of Len Wein he also gave us The Lurker in Tunnel 13, a Swamp Thing story featuring M'Nagalah the All-Consuming, the shoggoth-like father of life on Earth and fountain of all human knowledge. Swamp Thing causes a cave-in at the mineshaft where M'Nagalah is awaiting the proper alignment of the cosmos that will allow him to conquer the universe, destroying him in the process (at least temporarily, anyway.)
Later on, Krona uses the Cosmic Cube to kill Galactus. And then converts his corpse into a house.
Hawkeye does this to Krona himself thanks to one of his trusty arrows.
Hawkeye: Last arrow I had, TNT arrow.
Lady Deathconquered Hell by killing Lucifer. This was subverted when it was later revealed he was alive and it was implied he'd only made Lady Death think she'd killed him. Played straight when she kills him for real later on in Judgement War. She has also defeated and killed a number of high-ranking angels, demons, gods and primordial forces. In Dark Millenium a traveler refers to her as the Godslayer.
Legion Abstract: Doesn't sound noble, until you think about it: for Mon, the Time Trapper isn't a person so much as he's a force of entropy; if you kill him, is it murder or experimental physics?
Big BadDarkhell from Les Légendaires did this in his backstory. Before the Legendaries form to oppose him, he had to face the rivalry of Skroa the Cunning, a Demonical bird sorcerer. Not only did he defeat him, but he also trapped him inside his castle as a test subject and eventually de-powered him by turning him into a regular bird.
The Martian Manhunter explained how things work in the DC Universe in New Maps of Hell when they discovered the "god" they were fighting (who'd ravaged Mars in the distant past) was merely a highly advanced artificial intelligence with, well, a god complex.
"We're the Justice League. We've beaten up real gods and made them cry. You are nothing to us."
In a similar vein, though on a smaller scale, Count Vertigo was able to defeat and nearly kill Kanto, Darkseid's master assassin, in the pages of Suicide Squad.
The Mighty Avengers once defeated Shuma Gorath, one of the most powerful and evil beings in existence. To be fair, there were a few things in their favor: the thing they defeated was a mere fragment that was trying to establish a beachhead to bring in the rest of it, and they defeated it by empowering and invoking another deity.
Monstress: In Issue 18, Maika and Zinn combine the power of two of the mask fragments in order to obliterate a Monstra which is emerging from a tear in reality above Pontus.
The Súper at the end of "El bacilón". OK, you have an urgent necessity to go to the bathroom, but the unstoppableMuck Monster that has been terrorizing the city for the last week is obstructing your way. What do you do? If you're the Súper, deliver a SINGLE slap so that it dissolves into nothing and stops obstructing your way. No more Bacilón. But, unfortunately, this does little to help him relieve himself.
In "La máquina del cambiazo" ("The swapping machine"), Mortadelo is warped into a creepy old castle through the titular swapping machine, and a bat enters the TIA offices instead. Filemón tries to catch the bat so they can swap it back with Mortadelo, when the bat suddenly turns into a very menacing (for the comic standards) Count Dracula. Unfazed, Filemón delivers a single slap to his face, leaving the vampire groggy, and drags him by an arm mumbling: "Yeah, such a moment for counts to show up... Come on!", before kicking the Count back to the machine.
Can't forget the time Luke Cage beat the shit out of Doctor Doom◊ for not paying his well earned $200. After Cage saves Doom's life from a third party, Doom forks over 200 dollars and they part ways amicably.
Nova: At the end of volume 7, with a little help from Sam Alexander, Richard Rider tears an Eldritch Abomination out of himself.
Previously, during the climax of Annihilation, he also went toe to toe with Annihilus (who approximates this trope), and literally tore him inside out.
Xadhoom, a Physical Goddess if there is one, is practically a living star in a humanoid form. She absolutely hates the Evronians, who destroyed her homeworld. Physically, Evronian warriors are on par with humans, and their weapons cannot even scratch Xadhoom, not even the starship-grade ones, while Xadhoom can annihilate their ships without effort. And yet, the Evronians defeated her twice, and nearly got her twice again:
her first defeat was in the very issue she debuted in style, when a group of warriors dismantled their ship's engine to put together a forcefield capable of resisting everything she could use except that one attack that would have killed her and destroyed Earth. Had not they been forced to use the local power plant to power it (meaning One could just shut it down), Xadhoom would have been defeated then and there;
the first near defeat was when they attacked her with a weapon capable of absorbing even the power of a star. That was working... But not nearly fast enough to prevent her from retaliating;
when Xadhoom went to destroy their mobile worldship, the defense fleet had an improved version of the forcefield projector mounted on one of their ships. They snuck up on her, fired... And Xadhoom, having noticed them trying to hide from her, dodged and had them hit another of their ships, before disintegrating both;
after Xadhoom routed the defense fleet, they pulled out something she could not destroy: the survivors of her people. They forced her to surrender, and realized how they could kill her and were about to do just that when Paperinik freed the survivors... At which point Xadhoom promptly broke out and started exterminating the Evronians.
Moldrock, the ancient ruler of Corona, may be less powerful than Xadhoom, but is a Physical God himself with enough firepower to conquer a planet by himself - and he proves it when he attacks Duckburg and casually defeats the US troops trying to stop him while being weakened. And he's been defeated twice:
We first meet him while he's stuck in Everett Ducklair's Pentadimensional World, a prison dimension that drains his powers (hence why he was weak when he conquered Duckburg: he had not yet fully recharged his powers after escaping his prison), with Everett having defeated him with a weapon that literally stopped his subjective time and then put a suppressor crown on his head while he was paralyzed. Everett and his accomplices did the same to his followers, all empowered by fractions of Moldrock's power.
Later, after many events that drained his power even after first escaping his prison, he returns to Corona and, without even recharging his power in full, retakes control by defeating the entire planetary army while making care of not killing anyone and demanding their surrender the entire time, and later corners Paperinik while he had just supercharged his suit with the full energy of a large power plant. Knowing he's going to lose, Paperinik decides to at least get the satisfaction of punching him in the face with all the power stored in his suit... And, to everyone's shock, knocks Moldrock out cold.
At one point the protagonist has the nerve to use his Compelling Voice power on God himself. I'm not kidding. He actually tries to make the Creator of everything do his bidding! And loses an eye for his trouble.
Of course, this overlooks the far more impressive fact that the Saint of Killers started his career by shooting the Devil in the face and ending it by doing the same to God.
Jesse's climcatic fight with Cassidy the vampire is also portrayed this way. Given that Cassidy has Super-Strength and can No-Sell a bullet to the brain, Jesse, Badass Normal though he is, seems to stand no chance against him, but Cassidy is going through a serious Villainous Breakdown, so Jesse's superior will and grit get the better of him.
Rex Libris has this sort of thing as part of his job. As a public librarian. He even calls Nyarlathotep a wuss.
Runaways: Technically, they only have to survive long enough for the Gibborim's time on this world to run out and wait for the baddies to fade away, but given that the fight involves Molly throwing Victor at one's face, it still qualifies.
In Secret Wars (1984), the Beyonder (a being "from beyond", with absolute power) takes a number of heroes and villains and makes them fight among themselves. However, Dr. Doom does not play the Beyonder's game, and arranges things so he can attack and defeat the Beyonder himself, claiming his power.
From the same event, Captain America holding his own against Doctor Doom (with the Powers of TheBeyonder). Sure it was Beyonder who got took down Doctor Doom but Captain America stalled him.
Sláine (Mac Roth) from 2000 AD does this more than once. Admittedly, the biggest Eldritch Abomination that he faced, the High Cythron Grimnismal, was just finishing off his regeneration when Slainé and his party arrived, and could be brought down by the cutting of a few feeding tubes.
The Mighty Thor much like his frenemy Hulk, the God of Thunder has done this on multiple occasions.
Thor has defeated the Destroyer, which was built to fight the Celestial, the makers of the Multiverse.
Thor once delivered The Worf Effect to the Phoenix Force, a being that existed since the dawn of time (see below in the X-Men examples).
Thor has defeated Thanos, although it was retconed into just being a powerful clone, when they actually fought in Infinity although Thor got some good licks in, Thanos overpowered him instead.
In the Chaos War event the Prince of Asgard comes face to face with Glory the physical embodiment of an entire pantheon of dark gods and worlds they are worshipped in. What does Thor do? Kick the Glory’s ass of course, although the titanic effort sends Thor crashing back to Earth where he reverts to Donald Blake.
Thor has also repeatedly humiliated Galactus by staggering him by flying into his face, knocking him over or in the Distant Finale seen in Jason Aaron’s run actually defeating him. Thor (2020) had Thor made into a Herald of Galactus so he could help Galactus against Galactus's former boss The Black Winter (who eats entire universes). Not only did Thor kill Black Winter, he also kills Galactus too and uses the guy's funky purple helmet as a palace gate. Galactus was brought back to life (in a fashion) ironically by Silver Surfer.
In Sonic Universe #4, Shadow, Rouge, and Omega travel to the Special Zone and challenge Feist for his Chaos Emerald. When they fail (for the second time in two days) he taunts them, and invites them back tomorrow because they amuse him. Omega responds by pumping him full of every round of ammo he has. It doesn't kill him, but it does stun him long enough for the trio to grab the emerald and teleport out of there.
It seems to be a common occurrence in Sonic Universe. Four issues later, Sonia and Manik did this to Perfect Tikhaos.
And again in Sonic Universe 25-28, where Silver the Hedgehog struggles against Dark Enerjak. Dark Enerjak can't be beaten, and everything doesn't even scratch him. He defeated all the heroes and villains alike of his universe, leaving only a few around for entertainment value, and has left only Silver and his own daughter, Lara-Su, to oppose him. Besides summoning armies made from all the souls he's taken and hitting Silver with Angel Island, he has a wide array of Chaos powers to add to his invulnerability. Silver eventually realizes that, indeed, he can't stop Enerjak — nobody, not even Super Sonic or Shadow's powers could. So, he uses his own powers to capture Enerjak's attacks and reflect them back at him. Enerjak, arrogant as ever, keeps falling for the trap, until he's so injured he tries to attack Silver physically... only to be defeated by a last, final blow from Lara-Su.
In The Amazing Spider-Man (1963) #270, Spidey took down one of Galactus' former heralds, Firelord (also one of his most powerful heralds ever). Without getting hit even once. Firelord got so angry he swore he would kill Spider-Man with his bare hands. Guess what. He failed. Miserably. The only reason he was gonna use his bare hands at all was because Spidey destroyed his Firestaff. Although, technically this wouldn't be considered punching out Cthulhu, rather "Did You Just Punch Out Cthulhu's Right Hand Man", which is a pretty big accomplishment in itself. This is an alien with so much raw power that he could conquer worlds and destroy planets with the slightest effort, a alien chosen by Galactus (freaking GALACTUS) to be his herald. And he's defeated by a human in a spandex spider-suit.
Spider-Man has also beaten both Thor and Thanos. Not kidding. Hereand◊ here.
In the Smallville Season 11 comics, Superman is strong enough to make Hades bleed with a punch. He eventually defeats the god by grabbing him and threatening to throw him into outer space, where he would tumble through the void helplessly, forever. Hades becomes so terrified of suffering such a fate that he surrenders and returns to the underworld.
Lex Luthor has made a career out of trying to punch out Cthulhu, in the form of the Big Blue Boyscout himself. In Last Son he finally gets the chance to kill a Kryptonian, killing one of Zod's henchmen in a one-on-one confrontation.
When Superboy and Supergirl — the same two who could pull an entire galaxy's worth of planets at any time — face Darkseid at the climax of Legion of Super-Heroes's The Great Darkness Saga'', amped up by Highfather to be able to ignore the depowering effects of a red Sun, they knocked him around for a bit but he still nearly kills them.
For the Man Who Has Everything: Mongul breaks Wonder Woman's arm and mops the floor with her, then gets Superman in a death grip. He finally gets taken out by Robin, who cleverly uses the Black Mercy as a weapon. A rare "saving the day" moment for Jason Todd.
During a fight with Superman, Arion turned into the titular entity. He still lost. So the Man of Tomorrow literally did punch out Cthulhu.
The Tales of Cthulhu short story "Alimentary, My Dear Cthulhu" is a detective story pastiche where the victim is one of the Great Old Ones, killed in the library with the candlestick. Out of sexual jealousy.
Another DCU example is the Teen Titans versus Trigon. Big, unspeakable, demon lord. Has multitudes of worlds bowing to him in abject fear. Yet, in their first outing a group of "mere" sidekicks and new characters, none of which were old enough to legally buy booze, take him down. A couple years later, they do it again.
Circuit Breaker was able to cause the universe-ending god, Unicron, to scream in pain by attacking him with cybernetic implants she made herself. Granted, she was left catatonic afterward, but still...
Surprisingly, even Galactus has done this. After getting a new purpose and a power boost thanks to the The Ultimates (2015), he successfully defeated Master Order and Lord Chaos. Bonus points for literally (well, sort of) punching Master Order in the process.
Wonder Woman (1942): When Diana fights Mars she easily hands him his ass despite him being an Anthropomorphic Personification of the violence of war. She can't properly kill him with the weapons she has on hand, he'll just reconstitute himself, but he can't defeat her either.
Wonder Woman (1987): Diana defeats Cottus, one of the hundred-armed fifty-headed Hecatoncheires, without even being able to see its full form by aiming her spear at its loudly beating heart, and when that just slows it down a little she breaks what appears to be a floating staircase it's clinging to which is actually its spine.
Wonder Woman finally killed Ares the God of War in Wonder Woman (2006). She didn't just "beat" him or "banish" him — she killed him. By smashing in his skull with a battleaxe. Of course, Ares isn't completely out of the story yet. Even gods have a hell after all.
She also literally punched out Zeus in the same volume when she had enough of his dickery.
The Wretch, a little-known superhero, uses Satan's Literal Genie status against him and, using a birthday card, turns Satan into a crayon. Which he puts into a packet, which contains Beelzebub, Bhaal and Lucifer crayons as well.
Excalibur (Marvel Comics) has Rachel Summers quite literally beat Galactus in her sleep, and she literally punches out an alternate-universe version of him once as well. Justified because, being the Phoenix at the time, she's just as much of a cosmic power as he is. That being said, Galactus won the moral victory, because he pointed out that while the Phoenix overpowered him and he did, indeed, eat planets, the Phoenix's power came from the potential life of beings as yet unborn/created and asked who was the greater evil - him, who essentially mopped up after a civilisation/world that was dying, or her, who denied life to those as yet unborn. The Phoenix, still very naive as to the consequences of her actions, fled in horror. Also, Galactus was hungry when she overpowered him, and his power (while also tremendous) fluctuates based on how recently he's fed. Meaning that all of the planets whose defenses have been overcome by Galactus faced him at hisweakest.
Speaking of the Phoenix, very few things can threaten such an entity, and they're usually cosmic beings in their own right. We are, after all, talking about a being that has saved and destroyed galaxies and can do the same to universes, taking actions with multiversal consequences. The most notable character that the Phoenix is actually afraid of? Charles Xavier. As she relates in issue 52 of Excalibur (about The Dark Phoenix Saga), "I was out of control. Nothing could oppose me. Or so I thought, until I was confronted with the indomitable will and terrifying skill of Professor Charles Xavier." That's right. Not even the strongest psychic on Earth (not even in the top 5, on raw power, with Jean Grey, Rachel Summers, Cable (depending on the state of his techno-organic virus), Nate Grey, and Legion all having more to work with), relatively Weak, but Skilled by the standards of those he's taught, and he scares the crap out of something than scares Eldritch Abominations witless.
More Phoenix-related stuff; during the Necrom arc of Excalibur, Necrom (an immortal Evil Sorcerer of immense power, so strong and so dangerous that Merlyn opted to fake his death as part of a gambit to defeat him) was 'the Anti-Phoenix', wielding a fragment of the Phoenix's power. Kylun, a guy with no powers other than a cat-like appearance and the ability to perfectly replicate any sound he hears, goes toe to toe with him and cuts out one of his eyes. Sure, he was wielding magic swords, but considering that Necrom, after going several rounds with Excalibur, Micromax (a size-shifter who performed a Colony Drop on him) and Feron (a powerful sorcerer), and eventually takes Rachel going full Phoenix to defeat, after a bruising cosmic battle that left her in a coma, this is incredibly impressive. Oh, and he'd been fighting Necrom for years, beforehand, and very nearly killed him at least once before.
On a more physical level, the Phoenix Force itself got literally hammered by Thor◊ in Avengers vs. X-Men proving a big fiery space bird doesn't frighten the Son of Odin. However, this quickly turned into Nice Job Breaking It, Hero, as the Phoenix Force split apart and possessed Cyclops, Emma Frost, Namor, Colossus, and Magick.
Black Bolt, Onslaught, Kang the Conqueror, an evil alternate Professor X, Magneto, Stryfe and even Rogue have all kicked Apocalypse (the oldest and one of the most powerful mutants in existence, who's powered by Celestial technology)'s ass. Rogue in particular despite being weak compared to the likes Black Bolt, Onslaught and Stryfe outright killed Apocalypse with her Touch of Death in Excalibur (2019), and Hope Summers had to resurrect him.
During Inferno (2021), it turns out the X-Men were so good at this that in an alternate future, they'd slaughtered the Dominion, an entire collective of machine-gods who exist outside of space and time. The last one left grabbed an Omega Sentinel and threw her consciousness back in time as a desperate attempt to stop this future.
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