Mm... well, the first thing that came to mind was something like...

[ He gets a piece of scrap paper to sketch out something that would look roughly like this on a pumpkin. ]

But we can do something else if you don't like this, it's just one idea.

[ Since he realizes after drawing it that the smile is a little Cheshire-like, and honestly he kind of has mixed feelings about seeing this face right now himself. ]