18 year old acting out for attention?

Hi there, I'm a high school senior and I know someone in my cl who I'm 120% sure acts out on a regular basis for attention. Basically he says random things that have a shock factor to get people to react to him. It gets on my last nerve and I only see him for one period a day. Whenever he said something stupid like that I always hope nobody says anything but in most cases someone has to say something like "only you would say that steven!" prompting him to say something else shocking related to whatever he got a reaction from. Today when someone finally said "why do you even say those things?" I just said "he's doing it for attention," and of course he just went into denial. The only justification he could come with is "I have the right to say whatever I want." Ive just been kind of curious about this type of behavior from a psychological standpoint; do people who act like that for attention even realize why they do it? and what is the correct term for this type of behavior? Acting out seems too general.