Autism or something like that was my first thought too. That's how my kid would react if I took his phone away as punishment a few years ago. Except they were only 10 or 12 and their capacity to physically hurt me was limited. We had a few well intentioned teachers intervene with out knowing what was up with him and it would quickly spiral. IEPs were vital for everyone's benefit.This is a special needs student and it’s a teachers aide. I have no clue what happened here, but I can tell you that I have been the 1 on 1 teacher with 2 different teenage boys with autism who were both huge and would absolutely fight you if you fucked up. They were both super sweet kids that I loved, but you definitely could not parent or discipline them like neurotypical children. Schedule changes, waiting, access to reinforcers (like videogames or toys) was something you had to really be strategic about if you wanted to avoid a violent meltdown.
I am not trying to blame the teacher or excuse the kid's violence, just saying that I understand the situation.