It starts as a young Izuku is looking to a young Bakugo

Izuku: w-why are you so mean Kaachan?

Izuku cried out as it's revealed he is trying to protect another kid

Katsuki: hah, don't try to be a hero you damn Deku.

Katsuki said as he started to attack the young green bean with his goons

Until a certain attack hit Izuku's head, as if it triggered something in his body

Izuku started screaming in pain, not from his attacks, but from his body shaping and turning

The once fleshy body of Izuku, morphed into one of pure wood and what looked like moss
(It's not letting me put images but... its Baby Groot)

Katsuki and his goons stopped

Tsubasa spoke up

Tsubasa: h-he has a quirk?

Katsuki looked to the kid he was just punching... and scoffed

Katsuki: your welcome you damn Deku, I made you awaken your quirk...

Izuku: I... am Groot? I-I am Groot? I AM GROOT!

Izuku said first asking what Katsuki meant then started freaking out from his voice, then saw his body

Tears started to form in Izuku's eyes, as he saw what he became, his bullies far gone... then the kid he saved walked up to him

Kinoko: h-hey... thanks for saving me... Izuku right? Shroom

Izuku nodded and looked to his hand

Izuku: I.... I am Groot...

Kinoko chuckled softly: no I don't mind what you look like, in fact... y-your kinda cute... shroom

Kinoko said with a blush

Izuku reached his hand out to Kinoko as to hug her as someone who didn't start beating him up and accidentally started making flowers on the tips of his fingers

Kinoko returned the hug a bit flustered: h-hey... so... what do you want to call your quirk Izuku?

Izuku stopped hugging the girl and pondered not realized that the flowers were still on his fingers, which caused Kinoko to pick them and smell them

Izuku: I am Groot?

Kinoko: o-oh. I'm sorry, I just thought...

Izuku: I am Groot, I am Groot

Izuku responded to the girl telling her that it's fine

Izuku: .... I am Groot?

Izuku asked what his quirk name could be

Kinoko: hmm... sounds pretty on the spot... hey, wanna know my quirk shroom? It's not that powerful of one but I hope to be a shroom hero in the future

Izuku: I am Groot?

Kinoko breathed in and out and produced some mushrooms from the ground, only two or three was growing though

Izuku: I am Groot

Kinoko: y-you think I'd make a fine hero? T-thanks... let's be heroes together! Ok Izuku?

Izuku nodded with a smile and hugged the girl before going home to his mom

A few .... several... years pass and Izuku and Kinoko stay in touch... mostly cause she's one of the only few to understand Izuku

Izuku and Bakugo's "friendship" did kind of mend... but the self centered kid still felt he was the best

Then it was the day

Teacher: so, you all know what today is

The teacher said as he threw the papers into the air and the kids used their quirks as a swoll Izuku (as Swoll Groot) was moving his hands around in a partying motion

Teacher: all right all right, you know quirk usage is not allowed, right?

Katsuki: don't lump me in with these losers teach, imma beat them all and prove to be a better hero then them

Teacher: that's right, your planning on going to UA right?

Students: that school? Isn't it hard to get into?

Izuku: I am groot

Katsuki: we get it, your name is Groot deku...

Teacher: and Midoriya plans to go to UA as well

Izuku stood up and started playing Earth, Wind and Fire's "dancing in September" on a music player and danced a bit

Causing the students to laugh a bit but also cheer on Izuku

The Teacher also chuckled but clapped his hands: all right all right, turn the music off young Midoriya, all though that is a classic

As the class ended, Izuku left putting ear pods in what would be his ears and listened to some music from old

Walking... well, dancing under a tunnel, he almost missed a sludge villain pop out from a sewers

Izuku: I am Groot?

Izuku stood still as he pretended to be a tree, with leaves and flowers growing on him

The sludge villain turned, looked, and saw no one and went to leave

Izuku pulled a phone out of his chest and called Kinoko

Izuku: I am Groot

Kinoko: your doing WHAT SHROOM?

Kinoko asked before Izuku hung up, and rushed at the slime Villain and sent a right hook at it....

Which the villain absorbed

Slime Villain: so there was someone here, well... fuck... I don't know how exactly I'd get inside you, you'd probably be the most suspicious thing to hide in...

As he said this, a gust of wind was sent towards Izuku and the villain, but All Might had no clue that Izuku... wasn't a villain

All Might gathered up the sludge villain inside some bottles and was about to confiscated the Twiggs of Izuku, someone showed up

Kinoko: h-hey! Drop my friend SHROOM!

Kinoko shouted, ready to use her quirk if needed... then saw both, it was All Might... and Izuku was...

Kinoko: IZUKU!

Kinoko rushed to the head of Izuku

Kinoko: Izuku, are you all right shroom?

Izuku gave a smile: I am Groot

Kinoko: thank god... after this, you owe me a dog shroom...

Kinoko said with a pout and a blush looking away

Izuku chuckled: I am Groot

His head started to form some type of spider legs so he could walk a bit

Kinoko: thanks All Might for uh... saving him... but uh... are you ok?

All Might: yes young miss, and I apologize for attacking him... I assumed... I need to turn this one into the police. Please excuse me

All Might left (no second Slime incident)

Kinoko: so... you ready to get prepared for the UA exams?

Izuku: I AM GROOT!

Kinoko smiled walking him to a pound to adopt an animal

Kinoko: awwww, your so cute... I want this one

Izuku: I am Groot

Kinoko: we'll have this one

Man: well aren't you the couple, come Cosmo, you have a new family

Kinoko blushed while Izuku smiled sheepishly

Izuku looked at Kinoko: I am Groot

Kinoko blushed a bit: thanks, hey, you must be Cosmo

Comso looked up to the two, skeptical... and a bit nervous

Cosmo then lept towards the two and rubbed her head against Kinoko's leg

Kinoko: ok, let's go home now, ok Izuku?

Izuku: I am Groot