We used to have one of those, he transferred into the school in the middle of everything IIRC. I still remember how bad he smelled and the empty cow eyes he usually had when he wasn't upset about anything and it kinda worried me because small me has never seen somebody off like that before in a normal setting and had no concept of autism which wasn't really a thing in the public eye then. The only emotion little dude knew was anger. He'd fly off the handle for every little shit that happened to him, bad grades, being berated by teachers, being touched, having shit stolen from him, people doing something in a way he didn't anticipate.. it didn't matter. Corporal punishment in schools has moved out of fashion at that time where I lived and was something only practiced at home at best, so the teachers were ill-equipped to contain him. (although now that I think about it, I think a few teachers physically restrained him sometimes when it got really bad.. it was an eternity ago) Tard handlers didn't exist. Therapist and psychologists in school settings didn't exist. Tard schools did but it was rare that somebody was actually put in one and it was more for the "drown in their own puddle of drool/security scissors" kind of tards. In the end, they left it up to the other kids to beat him up for acting like a weirdo. And ho boy, they did. In the beginning there was rarely a day where he wasn't beaten into a pulp but he also didn't learn and still get upset about shit and got into peoples faces. He also seemed to have a very high pain tolerance, although he had no strength, which made beating him up exhausting. After a while, even the worst bullies were kinda lost what to do with the kid and he got beaten up a lot less and ignored a lot more.
Then one day he stopped showing up for school. Turns out his older brother (a completely normal, nice guy who was even kinda popular) lost it and threw him off a slide in order to kill him. Being the time it was, playgrounds were not tard-proof. He split his skull open. They saved his life and put a metal plate in but apparently he lost a few too many IQ points and finally ended up in tard school.