Hypothetically speaking, when a join mission with your friends slash rivals to capture a villain with some kind of a time quirk gone wrong from a burst of said quirk and a distance too close, they should freak out.
When they found themselves in the past inside a body that's not even their own, they should definitely freak out and scramble to find each other.
They absolutely won't take advantage of their circumstances and quirks. They certainly won't do whatever they wanted and create troubles for each other. They would surely search the villain to undo his quirk or find an authority to fix this.
They would be very careful to not make any changes in the past and try their best to act out the character of the body that they found themselves inside to not attract any suspiciousness towards themselves.
Nope.
Midoriya Izuku said 'no' in a flat tone. Todoroki Shouto disagreed quietly. Bakugou Katsuki shook his head negatively.
So, what's the protocols and rules for a time travel gone wrong again?
Dabi was minding his own business when a group of hooligans cornered him in a dark alley, trying to extort him for money. He grinned wickedly, heat gathering at the tip of his fingers. His blue fire was licking at his palms, ready to blaze and scorch them all. He was going to teach them a memorable lesson.
When he was a second away from unleashing his quirk, a short boy with green hair and freckles suddenly appeared out of nowhere and cleared his throat, gaining their attention in an instant.
"What are you doing here, brat? Get lost!" one of the hooligans shouted at the boy with a menacing grin.
The boy flicked his wrist and made a silent demonstration of his monstrous strength by shattering the wall next to him with a seemingly light punch. The hooligans immediately went white and they ran away in fear, passing the enigmatic boy harmlessly and went out of the dark alley without a single glance back.
"Show off. Mind your own business." Dabi muttered under his breath, already walking passed the boy, dismissing him to be another one of those vigilantes. There were many of them in this area after all.
Something suddenly shot out from the boy, wrapping itself around his body, capturing him in an instant and restraining him physically.
He immediately struggled against his binding, some kind of black tendrils made from energy that he couldn't burn with his azure flame.
The boy stood in front him, hands casually inside his pockets. The boy's green eyes emotionlessly watched his desperate efforts to free himself from the dark restraints.
"Who the hell are you?!" Dabi shouted with a ragged pant, tired from his useless struggle. The boy looked about the same age like his youngest brother, how could his quirk be this strong?
"You are coming with me and you are going to apologize to mom, Touya." The strange boy said in a deadpan tone, ignoring his question.
"How do you kno- mrfgh!" The black tendrils wrapped around his mouth, preventing him from finishing his sentence.
"Let's go." The mysterious boy said in an impassive tone, easily dragging him from the dark alley.
"Hello?" Todoroki Natsuo picked up his phone with one hand, the other one holding his can of soda.
"He lost it." His sister said calmly from the other side of the phone.
"What?" His heartbeat immediately raced despite his sister's calm tone, already assuming the worst. Did the old man snap and hurt Shouto again?
"Shouto lost it."
Natsuo slowly blinked his eyes, a memory of Shouto's wound and his mother being taken to the mental hospital flashed before him.
"Are you okay, sis?" He asked urgently, afraid that his little brother would snap from the pressure and hurt his sister like his mother once did to her youngest child.
"I don't know, Natsu." Fuyumi said hesitantly.
"I might already lost it and hallucinate the entire thing after all."
"What do you mean by that?" Natsuo asked in confusion, gripping his can of soda tightly.
Todoroki Fuyumi wondered how exactly was she supposed to tell Natsuo that their youngest sibling was currently shouting profanities at their father while using both of his fire and ice in their training room.
"COME AT ME, YOU SHITTY OLD MAN!"
A giant fireball went flying towards Endeavor.
"SHOUTO! YOU FINALLY EMBRACE YOUR QUIRK! I AM REALLY HAPPY!"
Endeavor encountered it with his own fire, a big smile on his face, almost manic even.
"SHUT UP!"
Fuyumi winced. Shouto was never this loud and temperamental, not even at his angriest moment. Did someone come and replace their sibling or something?
"Sis, I think I just heard our littlest bro shouting 'come at me, you shitty old man!' and 'shut up!' really loudly but that's probably just my imagination, right?" Natsuo said from the other side of the phone quietly.
Or they were having a really weird dream. That's another possibility that could be considered, Fuyumi decided.
It was a sunny and warm day. A boy with spiky hair and red eyes whistled joyously, escaping easily amidst the panicked people. Beneath the smoking hospital, a certain doctor was in his knees, sobbing in despair.
All his little children. All his creations. All of his hard work and dedication to the great All For One.
All gone. There was nothing left except a single message, written on the wall messily with a black paint spray.
A dare to his master. Childish and gleeful. Crazy.
All For One got many enemies from here and there in this vast world but none of them would be as bold and outrageous as this. None of them would be daring enough to propose something akin to a game like this to the evil emperor of the underworld, the boogeyman himself.
The doctor starred blankly at the writing on the wall, wondering how to report this to his master.
Just who?
'Catch me if you can, All For One.'