The crystal ball was presented in 1902 but John Waterhouse could never imagine that in 1953 the new owner of the castle where the painting was did not like the skull and made it disappear. It was in 1994 that, after being auctioned by Christies, the painting was analyzed compared with photographies of the Art Journal in 1908 and after X-ray it was possible to see that the skull is still there.
Creepy is not the skull but the owner who removed it.