Funny: One Punch Man

  • Saitama vs. Asura Rhino. Asura Rhino activates his berserker form and says it will last an entire week. At first, Saitama sounds worried about stopping him, but he works out what next week is and realizes that today was the special sale he was looking forward to and punches Asura Rhino's entire head off.
    • In the anime, Genos' reaction makes it even funnier, running up to Saitama to tell him that they have 4 hours left to be there and they can still make it in time, with a serious and excited tone, like it was a matter of life or death.
  • Genos's backstory.
    • Made funnier in the anime at how Saitama is noticeably fidgeting and Genos keeps talking faster and faster with the background music.
  • Genos's afro.
  • After seeing the lion get turned into a messy pulp by Saitama, the mole rightly runs like Hell. However...
    Saitama: found you
  • When the House of Evolution begins their attack, a praying mantis monster crashes through the ceiling. Before he can say his name, Saitama does his thing.
    "Pay for the ceiling!"
  • "Don't you dare touch this city....I LIVE IN IT!"
  • Genos declaring he wants to room with Saitama. "Hell no." "I can pay you rent." "Did you pack your toothbrush?"
  • One of the bonus chapters features the first, and so far only, enemy to put a visible injury on Saitama: Torako, a housecat.
  • Saitama explains to Genos why he's been troubled lately: "I'm not famous."
  • Saitama kills a car like it's nothing. Passersby, on the other hand...
  • After passing the hero exam, Saitama meets teacher Sneck, who, as you might expect, is a very Smug Snake. After hearing that Saitama and Genos are MUCH stronger than him, he goes off to disprove this by attacking Saitama while the latter is walking about, deep in contemplation. We see him throw one punch about to land... and the next frame is him buried headfirst in the ground, with Saitama carrying on as if nothing happened.
  • During Saitama and Genos' training match, it looks like Saitama is actually going to get serious and completely rock Genos' face off... only to end his punch about an inch away and then flicking Genos in the forehead. He then does the goofiest little march away after declaring that they're going out for some udon while the panel cuts to show that the blowback from Saitama's punch decimated the entire mountain range behind Genos.
  • Saitama discovers that C-class heroes get kicked out of the association if they're inactive for a week, after seven days of slacking off. He runs around the city only to find that it's finally peaceful for once. Tank Top Tiger then appears and tries to take him in, as Saitama running around is making people suspicious. Sonic shows up next and starts wreaking havoc in order to get Saitama to fight him, but Saitama initially refuses because he needs to find a bad guy. Then the penny drops:
    Sonic running around and destroying the surrounding area
    Saitama: Oh.
    Saitama pops up behind Sonic
    Saitama: Here's a bad guy.
    Sonic and the injured get carried off in ambulances. The last panel shows that the pavement has an imprint of Sonic's smiling face on it.
  • In the Sea King arc, when Sonic and Pri-pri-prisoner meet, Pri-pri-prisoner tells him why he was keeping himself in prison. Sonic remarks that he should stay in jail. Also when Pri goes "Angel Style" and declares that no one has seen him in that form and lived, Sonic thinks that he'd better go home.
  • During the meeting of all of the S-classes, the scene shifts to a sequence showcasing all of the S-classes in the order of their rank and their thoughts on the meeting... until it gets to Saitama, who, despite being only a B-class and not actually having been invited to the meeting, asks for some tea. The next chapter then starts off showing that yes, Saitama was given his tea.
    • A lot of the S-classes themselves are funny too, especially considering that this is the first time the readers see them. They've been set up as being the greatest and strongest of all of the heroes in the entire organization, but many of them are taking the meeting just as seriously as Saitama.
  • During his fight with Boros, Saitama punches Boros across the city-sized spaceship they were on as soon as the alien stops talking. Boros survived a full on, serious attack from Saitama but at the cost of his armor. The clincher? The armor acted as a Power Limiter.
    Boros: I've lost the armor that kept my immense powers under control.
  • After the invasion is over, Tatsumaki starts chewing out Saitama for rushing ahead into the spaceship and not respecting his lowly station as a B-Ranked hero, but most importantly calling him a "baldy" over and over again. Saitama then instructs Genos to tell her off. Genos tells her to shut up or he'll crush her. Cue Genos getting smashed into a giant pile of rubble.
  • Saitama deciding to enter a martial arts competition by disguising himself as Charanko. Also Genos' reaction to seeing Saitama wearing a wig, which was to call Dr. Stench and try to get him to fix Saitama's baldness.
    • When buying the wig, Saitama runs into Garou, who believes Saitama is trying to make a name for himself by defeating him, and attacks. His blow doesn't even faze Saitama despite driving him up to the ankles in the pavement, and he responds with a single blow that knocks Garou out. And the kicker? Saitama didn't know who Garou was, and was simply trying to talk to him while out shopping. And when Garou hit him, Saitama asks "Are you mugging me"?
  • When a group of S Class and high ranking A Class heroes begins raiding the Monster Association, there's a chapter basically dedicated to showcasing the abilities of those who haven't had much time in the spotlight so far, where they go up against members of the organisation with similar powers or attributes and completely wreck them. The funniest of these has to be "The Great Food Tub", a monster who makes his debut bragging how he's going to swallow all the heroes whole, only to be immediately eaten whole himself by Pig God.
  • When Garou asks Saitama why he's a hero, there's a build-up of 4 full-page images of Saitama picking his nose before he just says "It's a hobby".
    • Followed by a literally faceless Garou drawn in the corner the next page. You could say he didn't see that coming.
  • Saitama and Tatsumaki pushing each other's Berserk Button.
    Tatsumaki: That was dangerous! Look where you're deflecting things! Baldy!
    Saitama: Ba- (Beat) The fuck you call me, midget?!
    • Even better when you consider "Baldy" is actually a part of his hero name.
  • Chapter 104 is one long CMOF with Saitama and Tatsumaki.
    • They interrupt and resolve a dramatic confrontation between a nearly dead A-Class hero and the gang that deceived him just as tensions rise to their peak.
    Feather: I'm a hero and this is my climax!
    Saitama and Tatsumaki crash through the wall behind him
    Feather: NGOBH
    • Metal Bat is called to H City to take care of a rampaging monster, even though he would rather be at home taking care of his birthing cat, and plans to vent his anger on the beast. After a long trip delayed by backed up traffic, he arrives just in time to see the two one-shot the monster with their bickering.
    • When Saitama and Tatsumaki's fight takes them far away from their previous location, Saitama manages to get Tatsumaki to temporarily stop fighting until they get back to the Hero Association. When he asks her for directions, she gladly shows him the way by dragging his face through the ground.
    Saitama: Hey! Isn't this bad for my scalp?!
    Tatsumaki: Shut up!
    • Sonic spots the two and makes another attempt on Saitama's life, only for that attempt to fly back towards him. His speed and honed reflexes would get him out of this situation...except a dog did its business at the worst possible time and place. *slip*
    Sonic: CURSE YOU SAITA- *explosion*
  • The Volume 9 omake about the Blizzard Group pooling to get a car has a lot:
    • At the outset, we see the group heading for an impressive big black car... only for them to drive off in the tiny little rental hidden behind it.
    • After a week the group has pooled funds through part-time jobs. And then Fubuki walks in having snagged 2 million yen by herself. This leads to the group thinking she was getting it through...illicit methods. Turns out she was out bounty hunting, which was what she actually meant when using flyers to get money quickly.
    • And then the car is pointless because they get stuck in traffic going after a target. A target which is powderized by Saitama who was going on foot.
  • Fubuki trying to get Saitama to join her in a fairer fashion by having him and his pals (Genos, Bang, and King) play her group at fighting games. Bang lost because he never played a video game before, Genos lost because he doesn't know how to properly hold a controller without crushing it and thinking that pressing the buttons harder will make his character hit harder, and Saitama lost before he even started playing. But when King steps up to play, her guys get WALLOPED.
    • Then she has to treat Saitama and his pals to dinner. Which she delays by being finicky over counting calories.
  • In Chapter 70, Saitama meeting Tanktop Master in the hospital when he joins in on Saitama and License-less Rider's conversation.
    Saitama: That guy... He just barged into our conversation, you know him?
    License-less Rider: He's the S-Class hero, Tanktop Master.
    Saitama: Ah yes, I heard it on the news! The guy who got his ass kicked the hardest.
    Tanktop Master: At least mention that I didn't go down without a fight!
  • In the anime's opening, Saitama is seen One Punching a bunch of monsters in quick succession that are all ugly, monstrous and/or huge. But a couple frames show him destroying a cute (albeit knife-wielding) star-shaped creature, which was even smiling before getting shattered into dust by Saitama's fist.
    • Also, the moment where a lightning bolt strikes Saitama's bald head. He doesn't even react.
    • Despite how hot-blooded it is, his theme song is funny - it's essentially him complaining that he's super strong yet it's boring and he's unpopular!
    • The first episode of the anime shows us how overpowered Saitama is. Then the second episode shows us that even his godlike power has limits as he faces his greatest opponent yet: a mere mosquito.
    • The Paradisers, a terrorist group of bald men who are effectively too lazy to work, want to destroy the building belonging to the richest man. Not only do they initially destroy the wrong one, but they miss the fact that their target has a literal Golden Turd (a parody of the Asahi Beer Hall).
    • And we get to see poor Speed of Sound Sonic's balls greeting Saitama's fist in action. It.Is not.Pretty.
    • Episode 5: The Hero Association Physical Test Examinations.
      Everyone sees Saitama's capabilities
      Random Hero Wannabe: I'm going home.
      • One of the tests is Whack-A-Mole.
      • Later, while having dinner, Saitama and Genos both engage in a Super Spicy Mega Monster Udon Challenge. Saitama loses to Genos.
    • Episode 6: Saitama embeds Sonic into the pavement
      • Fubuki doing the next episode preview despite doing an Early-Bird Cameo. Eyelashes regretfully reminds her that she and the Blizzard Group won't appear in Episode 7 despite her hopes.
  • There're loads of awesome and heartwarming that happens when Genos keeps studying and learning from Saitama like a glimpse of his true power or Saitama's heroic actions despite only a few people witnessing or recognizing them. It's becomes hilarious, though, when it's shown just how thorough he is about everything there is to learn, such as the angle of Saitama's reclined position while reading a book. As if that's a factor in his powers.... OR IS IT!?