Well, that's unusual. Is there any possibility it could be ink from the newsprint transferring to his skin? I remember when I used to use printed newspaper my snow corns would get kind of a grayish cast to them but it wasn't in patches like that.
Nope, it lasted for quite a few sheds, and got a bit darker. He is a possible granite though. I have seen another pic of a super fire with a grey patch on its head. So I know it happens with super fires. Just don't hear about it often.