Alien Abduction!!1!
You cock your head and mimic his expression. This seems to cause him more confusion. (Aw, come on, haven't you had an annoying little sibling try to copy you? It's annoying.) Besides, your tongue isn't a foot long. So he makes some movements that you mirror. He seems a little irritated now. So he bumps the purple creature on the back. It turns around with the scalpel in its hand. Dude, you blew it. Better act quick....