Why does he do this? HELP ME PLEASE! ?

i think he's just trying to piss you off... get under your skin... Just tell him he's a jerk when he's being a jerk and ask him what he's looking at when he's staring at you... Simple. don't start to think or even act like he like's you because that will look suspicious... If your friend asks you whats up just tell her he's being annoying and tell her what he did.