Witch ball

Witch Ball: A hollow sphere of plain or striated glass hung in cottage windows in the 18th century to ward off evil spirits, but later often posted on top of a vase or suspended by a cord (as from the mantelpiece or rafters) for a decorative effect. Traditionally the witch ball is green in color, but that isn’t necessary. Sometimes the balls are made of wood, grass, or twigs instead of glass. The modern Christmas ornament ball is descended from the witch ball. According to an ancient tale, the ornament was originally placed on the tree to dispel a visitor’s envy at the presents left beneath the tree.

A Witch Ball also refers to a party held by Witches, were people are invited to dress up in Pagan costumes and celebrate.