"Self"
This was inspired in part by Ursula LeGuin's book "A Wizard of Earthsea." Just as Ged ran from the shadow that followed him until he finally faced it and discovered that the shadow was the other part of his soul....so we fear that part of us that we do not know. The crystalball holds the future of that self, gripped in the claws of a nightmare. Only when we truely look into the ball can we know our true selves and release the shadow of our fear.