Or it could be...just a sprite..
As for the sprite itself, I think the head of the skull could be smoother around the top, looks too rough. And if it's a human under it, he needs some ears(or you could lower the skull), and you could use the black outline color for the eyes, or put eyes in there, its like a plain eyeless and earless head with a skull on his head. And he arms are too jaggy, there are unnecessary extra pixels going along the arm, and right-side arm(his left) is hard to read too.
As for the sprite itself, I think the head of the skull could be smoother around the top, looks too rough. And if it's a human under it, he needs some ears(or you could lower the skull), and you could use the black outline color for the eyes, or put eyes in there, its like a plain eyeless and earless head with a skull on his head. And he arms are too jaggy, there are unnecessary extra pixels going along the arm, and right-side arm(his left) is hard to read too.