Katsuki Bakugo, a famous hot-headed vulgar student at U.A. High and wielder of the quirk Explosion is panicking.
Why, you ask? Well, let's take a few steps back, shall we?
One day, Eri visited once again the U.A. High because she wanted to see Deku.
Class 1A teacher, Shouta Aizawa, asked Midoriya and Bakugo to take care of the horned-girl. The two students accepted the request (Izuku with pleasure, Bakugo not that much).
But even so, Eri had a fun time at U.A., especially when she visited Nejire, Tamaki and Mirio.
But, when the three entered inside the Support Department Lab, a bizarre thing happened.
When Izuku and Katsuki entered, they were distracted by Mei Hatsume talking to them about her new invention, Eri decided to running around the campus without getting noticed.
Izuku and Bakugo noticed and started to search for her
They arrived in the campus and noticed that Eri was going to get hit by a quirk. Deku couldn't permit it. So, in an act of heroism, he tried to shield her but, in fact, it was futile since both of them were hit.
"Deku! You fucking idiot!" Bakugo ran towards to them but the moment the fog disappeared he found an unpleasant surprise.
He saw that Izuku became a child and Eri became a teenager.
"...What the fuck." Bakugo said, utterly confused.
Eri and Deku regained their senses, they were confused and lost.
"K...Kacchan?" Kid Deku said, recognized his childhood friend.
"Mr. Bakugo...? What...happened?" Eri asked.
"YOU!" Bakugo ignored the two and with his explosion blocked the person who hit Izuku and Eri with his quirk "WHAT THE F*CK HAVE YOU DONE?!"
"Ah! I-I'm sorry! Please, don't kill me!" The student begged.
"Name, Class and Quirk." Bakugo commanded at his terrified peer.
"H-Haruka Yoshiro! Class 1D, General Department! My quirk is Age Control, it can change the age of the person or a object that my beam hit!" Haruka said.
"When will they return back to normal?" Bakugo said with a calm, but filled with anger, tone.
"I-I don't know!"
"THE FUCK DO YOU MEAN "YOU DON'T KNOW"?!"
"Eeek! I-It can change! Sometimes it last 24 hours, sometimes a week, sometimes a month, sometimes even a year..." Bakugo caused an explosion near Haruka, which it scared The Living Daylights out of her.
"Get the hell out of my sight, before I make you explode like a firework." he ordered. The girl ran away.
Then, Katsuki turned towards Deku and Eri.
"Aizawa is gonna fucking kill me...I should make them hide in my dorm for a while, so it won't cause any problem." The Angry Pomeranian took his backpack and, with a calm tone, asked Izuku. "Deku, can you please hide here?"
"H-Huh? W-Why?" the little kid asked.
"We're gonna play a special version of Hide n' Seek. Hide here and you'll be safe." Bakugo said.
"Oh, okay!" Izuku was easily fooled and hid inside the backpack.
"Eri, follow me." Katsuki said, Eri nodded.
The three nearly suceeded at going to Bakugo's dorm but, unfortunately, they were stopped by Kaminari and Mineta.
"Fucking great, I was stopped by the perverted freaks of the class." Bakugo thought.
"Hey, Bakugo! Have you seen Midoriya?" Kaminari asked. "It's been a while since everyone saw him."
"Why should I give a shit about that nerd?" the angry blond young man asked.
"I mean, you left the classroom with him, so I thought you would know where is he." Kaminari explained.
"Well, I don't know where is he, so let me g-"
"Hey, Bakugo, who's that bombshell?" Mineta pointed at Eri. The girl, even if she didn't understood what he said, started to feel uncomfortable.
"That's none of your fucking business, Small fry!" Bakugo saw Eri's reaction and tried to make Mineta go away.
"Oh, come on, I just want to know her name and...know her better." said Mineta, drooling.
Bakugo held with all of its might the impulse to actually commit a murder without using his quirk.
So, he ignored them, took Eri and with his explosion arrived in his dorm in a instant avoiding the two.
In Bakugo's dorm, He freed Izuku from his backpack and Eri sat on the bed.
Katsuki sat on a chair, elaborating what to do now.
"...I'm sorry..." Eri said, shyly.
"For what? For that grape pedo harrassing you? You shouldn't be sorry, he should!" Bakugo tried console Eri.
"No, I-I mean...If I didn't go outside by myself, we wouldn't be in this situation." said the silver-haired girl.
"Don't wovvy!" Kid izuku approached Eri. "Evevyone makes mistakes! I'm suve Kacchan is not angvy at you, Miss!" he smiled
"He's right. I'm usually angry with everyone, but I go soft with kids." said Bakugo.
"...I see." Eri smiled. "Thank you, Mr. Deku! Thank you, Mr. Bakugo!"
Katsuki's heart squeezed.
"Well, I'm going to take some new clothes for you, don't leave this room and don't speak to anyone unless it's me, okay?" Bakugo said. Deku and Eri nodded.
While Bakugo was outside, Eri and Izuku chatted.
"Hey, miss!" The broccoli-haired child asked.
"Hm?"
"Do you know Kacchan?"
"You...introduced him to me. You said that he's a nice person."
"I did? I don't think I know you."
"Well, you saved me from a villain, only that you were bigger than me."
"Veally? I fought a Villain?" Izuku's eyes shined from happiness.
"Yep! You and Mr. Bakugo are training to be heroes!"
"I'm a Hero?! And Kacchan too?!"
The two continued chatting until Bakugo returned.
"i'm back." he said. "I've brought some clothes for you."
It was a white shirt with and skirt of Eri and a red shirt and blue pants for Deku.
Eri took off her red dress and put on the clothes Bakugo gave her.
During the process, Katsuki, for obvious reasons, didn't not watched her changing. (She may still be a child, but now she has the body of teen and also, Bakugo's mother raised him up properly).
"Can I turn around now?" he asked.
"You can." Eri said. "I like this shirt!" she continued, happily.
"Good to know." Bakugo responded, with a hint of a smile.
"Hey! Bakugo!" Some knocked at his door. It was Ochako Uraraka, one of his classmates.
"What do you want, Round face?!" Katsuki said.
"Are you okay? You haven't left your dorm in the entire day!" she said.
"Leave me alone-"
"Bakugo. I gave you and Izuku the task to take care of Eri, where is she? And where's Midoriya?" Aizawa interrupted.
"Fuck." Bakugo thought. Since he knew he was doomed, he opened the door the his teacher.
When the others saw Eri and Izuku, they were stunned.
But then, all of the 1A students were happy.
"How cute!" Mina hugged Kid Izuku.
"Eri...you look wonderful!" said Uraraka.
"T-Thanks..." Eri said.
Everyone reacted well to the two.
Well, minus Aizawa.
"Bakugo, we need to talk." he said. Katsuki gulped.
After that, he explained eveything to Aizawa and since Bakugo didn't report to him immediately what happened, he got under house arrest alongside Mineta, since he was technically sexually harrassing a child.
When Bakugo was cleaning, he got a visit by Izuku and Eri (now returned back to normal, who wanted to say thanks and help him cleaning. Katsuki, while being a tsundere, accepted the offer and the 4 continued cleaning.
But he had to admit, what happened yesterday was fun.