Cancer guy +Cancer girl+ (?)guy= weird situation?

Nearly four weeks ago this guy started sitting beside me and my Cancer guy-friend in class. We clicked since day one, which is weird, because I am really bad at social zing. He also clicked with my cancer friend. Later on I noticed that he will always comment on anything I do or anything related to me in general. What I wear, what I read, even when I draw or take notes ...

When I came to class today he told me that I'm late three times in a row. (I couldn't believe he would say something embarrassing like that) because he said it in a questioning way. My Cancer friend strately told him he was acting like a stalker, Unkown guy said he was only paying attention. He's even comfortable telling me I'm not supposed to do this and that. My cancer friend was so angry when he knew xD.

Also, when I sit in class he would sometimes slide the computer chair back and stare at me, I try to ignore it often, but once he was staring up close for a long time that it weirded me out. I told him what's wrong and he smiled and shrugged it off.

He and my cancer guyfriend (We are really close, basically college best buds) always throw remarks at eachother, it's supposed to be in a funny way most of the time, but now I noticed that they are not getting along. My Cancer friend compares the unkown guy to the "Annoying orange" lol.

This is how they greet eachother:

Uknown guy: Hey mean

Cancer guy: Hey lame

What do you think his sign is?

And does he like me or something? because he's acting really weird.

What about my Cancer guy-friend?