Two Year Old or Sociopath?

Let's suppose that as you drop your older son off at preschool, your younger son spots the younger sibling of another student. He steps toward the 15 month old, who is half his age, and smacks him in the face. He moves to do it again as you grab him and say, "No!" Then he throws himself on the floor sobbing while you try to explain to the other kid's mom what the hell happened.

Please note that he stops sobbing and grins the second you pick him up.

And let's also suppose that when this same child actually gets mad, he bites. He has bitten everyone in the family more than once and not even being bitten back has stopped him.

Oh, also suppose that this child has literally the most charming smile you have ever seen.

Would you be worried? Would you think, "I know 2 year olds are obnoxious, but this seems a little extreme. I mean, his siblings are actually afraid of him!" Would you start thinking that maybe it's time to find a therapist? 

Or would you just assume that he's going to run a cult or a small African country someday and try to stay on his good side? 

BTW, this all COMPLETELY HYPOTHETICAL. Of course no child of mine goes around hitting and biting people.