The Medusa costume is a costume primarily for women and girls and based on ancient Greek mythology. Medusa was a Gorgon whom Athena cursed so that anyone who looked at her would turn to stone, and her hair became a nest of snakes.
The snake hair is the primary component of the costume, though ancient Greek-style clothing, such as a peplos (easily made with a sheet, safety pins and a belt) is a common addition. The hair can be achieved through braiding and hairspray, or a headpiece with rubber snakes or pipe cleaners attached to it. Green face makeup is also helpful for a more repitilian look.