Search Results: having eye contact with a guy

So i met year and half ago one guy. We were in same group and we set next to each other but we've never really talked.
He acted different torwards me, we had eye contacts like prolonged and he was like he want to came closer when he was sitring next to me.

So 6 months later on college he always seems to noticed me and stare in my direction. I taught that it was in my head but it wasn't. We had one mutual friend but he seemed he don't know that we know each other.
Also he acted pretty strange sometimes and it acted like crazy person.
Sometimes even my friends don't notice me but he does. Once he stopped and looked at me until i passed and then he continued to go where he was going. When i would came closer he would be quiet with friends and when i would move he would be talktive and looked at me.

So my friend (pther in his group) told me that he has something with one girl who knows his bffs (2 of tham) and they are always together and i saw tham kissing. So for a year he acted strange even he was with her and it was strange.
I can't write all scenaries cause that would be too long.

So guys what do you think? I liked having eye contact with him but after some time i stopped to do that and he continued. In one period he stopped but he started it again. I don't want anything with him he's cute but strange. I don't want to talk to him eather he could deny it.

Why would someone do that?