On a play ground

Izuku was standing in front of a kid who was getting beat on. There was also a kid with blond spikey hair and 2 others behind him. They were the ones who were beating on the kid.

Izuku: Hey stop being so mean Kacchan. This isn't right.

Bakugo: Oh, shut up you Deku.

Izuku: If you don't stop this than... than... THAN ILL STOP YOU MYSELF.

The blond kid named Bakugo made a fist and punched his hand causing a small explosion to happen. Kacchan than made an explosion behind him charging at Izuku. He than threw a giant right hook at Izuku and punched him in the face. Izuku was knocked down to the ground. Izuku stood on one knee though and spoke up with a bloody lip.

Izuku: If you were a real hero. You would be helping the kid. Not hurting him. Or others weaker than you.

Bakugo looked at him with anger in eyes. He was furious and took it out on Izuku. He grabbed his shirt and started to throw multiple punches at his face. He then threw Izuku near the kid getting beat up and looked at him. He saw he was scared and even saw the kid silently say words.

Kid: Stay down please.

Izuku than got up again and now Bakugo was even more furious. He than turned around at Bakugo and looked at him.

Bakugo: WHAT you want more.

Izuku had a black eye scratches everywhere and bloody lip. Yet still he was standing and ready to fight and never give up. The next words he said though gave inspiration to himself and even possibly anyone who heard him say it. He said out of breath and on the verge of collapse.

Izuku: I can do this all day.

10 years later in a crowd near a school alley

A crowd was chanting and screaming around 2 kids who were fighting it out. One kid had green eyes and emerald eyes. While another had spikey blond hair. The 2 kids were Izuku Midoryia and Katsuki Bakugo. Bakugo threw a right hook at Izuku knocking him into a wall with trash cans.

Bakugo: CMON DEKU get up and fight me.

Izuku grabbed the trash can lid and tried using it as a shield. Bakugo just chuckled and blew up the lid and out of his hand. He than threw another right hook at his face.

Bakugo: Had enough.

Than just like when they were kids Izuku got back up and stood up to him.

Izuku: I can do this all day.

Just as he was about to throw another right hook at Izuku a girl with pink braids and yellow eyes jumped from the crowd and grabbed his hand.

???: Hey that's enough.

Bakugo took his hand back and started to lean into a punch towards the girl.

Bakugo: Back off you stupid bitch or else you'll get some.

The girl than punched Bakugo in the face kicked his knee (bending it the wrong way) and Bakugo went to the ground. The girl than put Bakugo in a head lock with her legs and grabbed his arms and had him pinned unable to move.

???: Tap out.

Bakugo: GRRR

???: TAP OUT.

Bakugo than tapped out as his neck was squeezed harder. The girl than quickly got off of him and Bakugo quickly got up.

Bakugo: Screw with me again and ill kill you.

???: You can certainly try.

Bakugo along with everyone else walked away. The girl than walked to Izuku who was on the floor watching everything unfold.

???: You ok?

Izuku: Um yeah. You didn't need to do that you know I would have been fine. Its not your problem to deal with.

???: I know but I was *silent pause* walking by and saw you. *puts hand out* My name is Mei Hatsume its nice to meet you er.

Izuku: *Shakes hand* Izuku Midoryia.

Mei: Well Izuku Midoryia why was blondy over there picking on you.

Izuku: He was picking on someone else. We were in class and he was talking about how he was going to be the greatest hero ever. A kid said he wanted to try for U.A. but Bakugo just called him out. I stood up to him and told him to knock it off. He kind of found me later and then started a fight with me and then here we are.

Mei: Why didn't you use your quirk.

Izuku than put his head down in disappointment.

Izuku: I'm actually quirk less

Mei: Than why would you go against someone like Bakugo. Did you want to hurt him. Hell, it seemed like he knew you and by the looks of it you hate him. Did you want to kill him.

Izuku: I don't want to kill anyone. I don't like bullies. No matter who they are where there from or what they may have done or even what quirk they have.

Mei's head: He really is a perfect candidate. I have to have him.

Mei: Well you passed.

Izuku just looked at her confused.

Izuku: Huh?

Mei: Tell me do you want to try out one of my babies.

Izuku just turned pale and was shocked.

Izuku: I don't want to do any baby related things I'm just a kid.

Mei: TRUST me.

Izuku didn't know why but he felt like he could trust her. So, he reluctantly went with her. They walked all the way to U.A. While they were walking she told him to call his mom Inko and say he is going over a friend's house.

Mei: Call your mom Inko.

Izuku: Ok.... Wait how do you know my mom's name.

Mei: Ill explain when we are there.

Inside U.A. in the supports course secret basement

Mei and Izuku were inside a lab with monitors everywhere and in the middle was a giant man-sized pod with blue vials inside it.

Mei: Alright take off your shirt and shoes and pants.

Izuku: OK I have followed you here and not ask questions but there is a line. So, I'm not doing anything until you start talking.

Mei: *Sigh* Fine. I'm trying to create a baby that can increase the humans physical abilities.

Izuku: W-WHAT. You were going to experiment on me. WITHOUT EVEN ASKING.

Mei: I was going to ask and even have you sign consent forms *mumbles* so you can't sue me if this doesn't work.

Izuku: What was that last part?

Mei: ANYWAYS. I have been experimenting with this formula I "borrowed" from Americas government. It was from way back in world war 2. They were trying to create super soldiers to fight the war. It never worked though. They still won the war but sadly the project got shut down. So, I decided to take a crack at it. The serum itself will genetically and naturally make your body stronger and grow. It uses a catalyst virus to scan and enhance any genes that deal with muscle growth/nerves/bone marrow/ basically anything the body needs to complete a task which if you really want to get technical is everything. ANYMORE QUESTIONS

Izuku: I uh um yes. Why me.

Mei: I have spent months looking for the perfect subject. The thing is though that back than the formula was made for people who were quirk less since quirks weren't a thing back then. Even than the subjects who tried ended up being failures because of their body's state. The formula only works for your body type or even your genetics.

Izuku: How did you find that out.

Mei: I hacked your files the government has on you.

Izuku: Uh huh.... *shakes head* But that doesn't answer my question. Why me. Couldn't you find some other quirk less boy. I'm not the only one out there roughly 20% of the population is.

Mei than looked him in the eyes and got a bit closer.

Mei: Sure, I could give this serum to a strong quirk user like All might or maybe even some other quirk less person. However, I choose you because the serum also shows who you truly are...... Think of it like this. A strong man who has known power all his life will lose respect for that power. But a weak man who knows the value of that strength and knows compassion will be a greater hero and stronger than everyone else.

Izuku was just amazed and felt so warm inside when she said that. He didn't know if it was because he was proud and felt good about himself or because his blush was really red because this girl does not know boundaries and her boobs are pressing against him.

Izuku: Thanks.... I think?

Mei: Ok great now can you please get in the photosynthetic chamber, so we can show the world that you're a true hero.

Izuku than takes off his shirt and shoes and keeps his pants on. He wasn't really that good looking and was very skinny and timid. He than got into the pod machine and got situated. Mei than started grabbing blue vials and putting them into the slots in the machines. She than strapped Izuku down and made sure everything was ready on her monitor.

Izuku: So, this serum is really going to give me a quirk.

Mei than turned around smiling and holding a needle

Mei: Not a quirk but your body will be stronger, faster, more durable and even heal faster than the average human. Now hold still.

Mei than used a shot on Izuku as Izuku closed his eyes from the slight pain from the shot.

Izuku: *sighs in relief* that wasn't so bad.

Mei: Um Izuku that was the penistila.

Izuku: Oh....

Mei: Anyways the vials with the serum will be Injected into your major muscle groups and spread throughout your body causing immediate cellular change. To stimulate growth, you will be subjected to photosynthetic light which will influence your body to use the serum to grow.

Izuku: Ok I'm good. Let's do this.

Mei than ran to her computer and started to work her magic and talking/ monologuing to herself.

Mei: Beginning serum injection in 3....2....1...GO.

The machine then injected the blue vials into Izuku causing him to feel a rush in his body and a sudden burst of energy gained. Mei than clicked a button and the pod doors began to close. Mei than went up to the window on the pod and tried seeing Izuku but since he is to shirt you can't see him through the window.

Mei: Hello? Izuku can you hear me?

Izuku: It's probably too late to go to the bathroom, right?

Mei than chuckled and went back to her computer and then went back at it and started to run diagnoses and talk to herself again.

Mei: Subject vitals are normal. Beginning procedure now.

The pod than began to emit a bright light threw the small window.

Mei: Power at 10%.... 20%......30%......40%......50%.... Vitals are still normal.

As the power being given to the machine increased so did the light in the machine.

Mei: 60%...... 70%.

Just as she said that though Izuku started to scream in pain.

Izuku: RRRRRRRRAAAAAAHHHHHHHHHHH

Mei than jumped off the computer and started to banging on the window.

Mei: IZUKU ARE YOU OK...... I'm stopping the experiment.

Izuku: NO.

Mei Just looked back in shock.

Izuku: I CAN DO THIS KEEP GOING.

Mei than reluctantly went back to her computer and continued with her experiment. As she was increasing the power though the lights in the room and even half the city started to flicker.

Mei: 80%....90%......100%. POWER IS AT MAXINUM CAPACITY. SUBJECTS VITALS ARE HIGH.

The lab than started to have sparks fly near the lights and power outlets and screen monitors. Than after the sparks stopped the light slowly went down until the window was dark again. Immediately Mei shut down the machine and opened the pod doors.

Mei: IZUKU.

The doors to the pod open with steam flying out of it. Than there stood in the pod a bigger and toned Izuku. His muscles were insanely toned and big and he was now a lot taller.

Mei than developed a nose bleed.

Izuku: Wow uh hehe this feels weird.

Mei: And how do you feel.

Izuku: Taller.

Izuku than tried taking a step but his legs were so weak, and he fell. Mei caught him though. Mei caught a big strong super toned sweaty and good looking Izuku. Making her blush and redder than blood.

Mei: *blushes* Well you look a lot taller (in head: among other things) You probably going to need some new clothes. W-wait here.

(Its alot like this scene from captain america) 

https://youtu.be/bmWLLempSyI

Mei than got him on a chair and gave him some clothes. Izuku put the shirt and new pants on. They were still small though and just outlined all his muscles.

Izuku: So, what now?

Mei: F-for now. You rest. Ill test you tomorrow. So, go home. You earned it.

Izuku: Ok.... Wait how am I going to explain this to mom.

Mei: Ummmm...... growth spurt?