Uh, his white hair? Maybe. He’s not really very physically odd with a glamour on.
Maybe his inviso-tail? He’d figured out he has a tail, about three months ago, even though the glamour hides it and usually keeps it from interfering with solid objects other than plants and earth. He has to concentrate to have it affect the rest of the world. He’s felt it out with his hands and it seems to be just long enough to have a couple inches drag on the ground and is thicker at the base than at the tip. Fleshy.
He doesn’t know much more about it. He’s learning how to use it.