The Light of Eternity was an electronic device that was owned by a fortune teller that Lazzor of the Woolies sent Samurai Jack to.
The fortune teller kept the light in a back room behind some curtains and only showed it to Jack after he had shown him the Ancient Scroll of the Woolies. The fortune teller remarked that the Woolies were old friends and brought Jack to the light. It was an electronic device which was a pad on the ground which a thick electric cable ran away from it. The light produced images of Jack's desires and his future, much like a crystal ball. The light was destroyed when a gang of Aku's Robots Assassins attacked them.