Bozo is used as an insult when a toxic person gets mad. It's usually said/shown on memes, or said over discord to make other discorders become upset.
UGHHHHHH is what people say when impersonating autisic people.
Hooman: Hey Elijha, isn't Noam so goofy?
Elijha: Bros been dumped into a box of chromosomes.
Hooman: UGHHHHHH