Quoted By:
So there's been a lot of speculation about how Light and Sound types will be appearing in X and Y. So much so, in fact, that folks are claiming Xerneas will be Light due his wacky horns, and Yveltal will be Sound because he looks like a tuning fork.
But I'm here to tell you that Y doesn't look like a tuning fork at all. He is clearly a lightbulb.
I know this for a fact because my dad works for Riot Games and was involved with the development of the new game.