Originally Posted by jtjumpshot
it actually scared the crap out of me.
It's possible that the same thing happened to him when you went to put your hand on his head (it's a dominant gesture - and he may not have seen it coming).
But it is also possible that he was protecting his food from you. That's not something you want to continue. Here's a recent thread on a similar situation. Wet Food Aggression???
Do check out the links given - there's some very good information there that will help you toward developing a leadership role and harmonious relationship with your puppy. Good luck