Dr Genus came before a massive beetle-like monster. 

Genus: Hello Carnage Kabuto, have you been well? 

He noticed a bunch of corpses. 

Genus: I see you've been killing my clones again. 

Genus: Do you feel better now? 

Carnage Kabuto: OF course I don't feel better! I am the House of Evolution's greatest threat! But you locked me in here beneath the earth! 

Genus: You are psychologically unstable. We couldn't control you, so it was necessary. 

Carnage Kabuto: Control?! HAHAHAHAHAHAHAHAHAHAHAHA! IDIOT! I am the perfection of your "new humanity!" In physical traits and intelligence, I far surpass the old human race! So you should take orders from me! 

Genus: No, you're a failure. Indeed, your capabilities are overwhelming. But you lack refinement. Kill me if you want. There are more where I came from. But listen to me. There's someone I need to get as a sample. But he's horribly strong. Only you can beat him. 

Meanwhile... 

Team (Y/N) found the House of Evolution and made their way downwards. 

Ruby: So, this is the House of Evolution? 

Genos: It is very spacious indeed. Hmm ... I'm detecting two life forms coming this way. 

(Y/N): Yeah, I sense them too. HERE THEY COME! 

Carnage Kabuto came charging in with Genus in his hands! 

Genus: That's him, the one on the right. 

Carnage Kabuto: THEN THE OTHERS ARE EXPANDABLE! 

Weiss: Is that a big beetle?! 

Blake: He's fast! 

(Y/N): MOVE! 

You, Ruby, Weiss, Blake, and Yang moved, but Genos was too slow and was slammed into the wall! 

Everyone: G-Genos? 

He was not responding. 

Ruby: GENOS! 

Carnage Kabuto: HAHAHAHA! MY NAME IS CARNAGE KABUTO! AND I'VE GOT A BATTLE-REST ROOM! Let's fight there! 

(Y/N): WHY Y- 

But Saitama stepped forward and he had a glare on his face. 

(Y/N): This power ... 

You sensed a powerful aura coming from Saitama. 

Saitama: You just turned Genos into modern art! You're going down! 

Blake: Did ... Saitama just- 

Yang: He's pissed man! 

(Y/N): You just made a big mistake, Bug! 

Carnage Kabuto just smirked, his confidence did not waver. 

Soon... 

You all arrived in a massive room. 

Yang: Geez, this is a big place. 

Carnage Kabuto: Big ain't it? It's the biggest place in the facility! This is where we test to see who's fit for ba- 

But he was blasted by Genos! 

Everyone: GENOS! 

Genos charged towards Carnage Kabuto going at full speed and- 

Genos: MACHINE GUN BLOWS! 

He punched Carnage Kabuto rapidly!

But then Carnage Kabuto punched Genos to the ground! 

You caught him. 

(Y/N): GENOS STOP! You're going to get yourself- 

Genos blasted Carnage Kabuto, but the big bug ate the blast and spit it back out! 

Genos: Impossible! He spit it back o- 

He was overwhelmed by it! 

Saitama: G-Genos are you okay? 

Genos was still alive, but his hair was like an afro now. 

Genos: Y-Yes. 

Yang: He's alive, but his hair isn't right. 

Saitama: Now you're asking for it! Bring it on! 

Carnage Kabuto: Heh, you're clearly different from those guys this morning. You're positively brimming with confidence. 

He appeared behind Saitama to hit him! 

(Y/N): This guy is fast alright. 

But then Saitama looked at him, and Carnage Kabuto jumped back! 

Genus: Wh-What? Did he just ru away? 

Saitama: What was that? 

Carnage Kabuto: If I had attacked just now, he would have killed me. What's with this guy? Tell me! How did you get such power? 

Saitama: So, you actually want to know? Very well. (Y/N), Ruby, Weiss, Blake, Yang, Genos, listen up! 

Yang: What is it? 

(Y/N): How did you get strong? 

Saitama: YOu must stick with it no matter how hard. I was able to get this strong in three years. One Hundred Push-Ups, one hundred sit-ups, one hundred squats, and run ten kilometers every day! 

(Y/N): Uh ... 

Ruby was writing it all down. 

Saitama: Also, eat three meals a day. Even just a banana will do for breakfast. To train your spirit, never use heat in the winter or air-conditioning in the summer. It'll almost kill you early on, and you'll consider taking a day off. But I wanted to be a strong hero, so I persevered every day, even if I vomited blood. Even when I felt so heavy, I could barely move, I did squats. Even if my arms made weird popping sounds, I did push-ups. One year later, I noticed a change. I was bald, and I got even stronger! In other words, train so hard until you lose your hair. 

Yang: 

https://youtu.be/ZZLE1WnqYC0

Carnage Kabuto: Are you serious? 

Saitama: If you're finding around with a "new humanity" and "evolution," you'll never make it. Human strength lies in the ability to change yourself! 

(Y/N): Hey, that's a good point! 

Genos: Master ... that's ... A BUNCH OF CRAP! That is jut strength training! It's not that hard! 

Yang: YEAH! IF YOU'RE GOING TO TALK ABOUT SHIT LIKE THAT, THEN IT'S NO WONDER YOU'RE A BIG BALDY! LOOK AT THIS HAIR! I MAINTAIN IT'S LOOKS ALL THE TIME NO MATTER WHAT! I CLEAN IT, WASH IT, AND BRUSH IT! 

Saitama: But ... there isn't anything else. 

Ruby: Well, I'm keeping my hair. 

Weiss: Me too. 

Blake: Yeah, I might not be obsessed with my hair like Yang is, but I don't want to go bald. 

(Y/N): (Sigh) Same here. 20 years old and bald doesn't look good on a resume. 

Carnage Kabuto: Then don't tell us your secret! You're not stronger than me anyway! You're making me so mad that I'm going to kill you little by little! CARNAGE MODE! 

He bulked up! 

(Y/N): HOLY CRAP! 

Ruby: Now he's mad! 

Carnage Kabuto: After I kill you, I'll head into town and rampage until next Saturday! 

He laughed as he punched Saitama in the face! 

(Y/N): SAITAMA! 

Ruby: MR. SAITAMA! 

Genos: MASTER!!! 

Saitama was getting punched over and over and over again as Carnage Kabuto kept attacking! 

Weiss: (Y/N), we have to- 

(Y/N): No, Saitama can handle this guy. Let's trust in him. 

Carnage Kabuto: DIE DIE DIE DIE DIE DIE DIE DIE!!! 

Saitama: Hang on a second, until next Saturday? That would mean that today is Saturday. And that means ... TODAY IS BARGAIN DAY AT THE SUPERMARKET!!!

Saitama screamed as he punched the upper body of Carnage Kabuto to shreds with blood spewing out like crazy! 

You, the girls, and Genos were in shock, and Genus, well- 

Genus: I'm done with my experiments. I'll change myself instead. 

Saitama: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAARGH! I SCREWED UP!!!