Medusa; guardian, protectress. Zeus adorned his shield with the head of Medusa as a means of protection. Images of Medusa were later used in Roman times to adorn gardens and doors, intended to guard the home from unwelcome guests and mishaps. The Medusa Spirit Ball is a modern interpretation in beautiful glass art. These enchanting hand crafted glass spirit balls are captivating at first sight, with their ribbons of glass rising from the pool of color at the bottom of the sphere, Medusa spirit balls are made to be exquisitely unique. Each ball will vary slightly, so no two will be the same.