VERY VERY CONFUSING guy friend?!!?!? HELP ME PLEASE!!?!?!?

Maybe he has something on his mind that's bothering him. Or maybe he's a little depressed and he has a lot of ups and downs. The best way to deal with it would be to confront him about it, try asking him when he's in a good mood, you'd be more likely to get a non-angry response then. Just tell him you consider him a good friend so you're concerned about him, and it confuses you when he's nice one minute and mean the next, and you never know if it's ok to approach him or not.