What do I do about my jerk roommate?

I don't have any horror drug or alcohol stories about my roommate but he is a total jerk to me. I am a freshman that just finished my first quarter at college. This roommate is always insulting me and doing immature things like farting on me, rubbing his hands on my head after he poops, and waking me up to insult me when i go to bed before him. I have blown up at him before but that didn't help at all because he turned that against me saying he is just joking around. It doesn't help that one of my other roommates is scared of the jerk roommate and goes along with everything he does and says I need to calm down and stop taking everything so seriously. I have no idea what horrifying things he has done to my stuff when I'm not around but I'm sure there's something. I am posting this because he can't even leave me alone while I'm on break as he just called me and pretended he called the wrong Brian (I heard someone laughing in the background when he said it) I am miserable living with someone that doesn't respect me at all and I don't know what to do to help the situation.