The Devil's Eye is the world's biggest diamond and the main reason of Madame Medusa's ambition. She would do whatever it takes to get her hands on the diamond. It used to belong to the pirates that buried their treasure in a cavern in Devil's Bayou. Kirika Yuumura and Mireille Bouquet heard about the Devil's Eye and must obtain it before Medusa. Bianca and Bernard help Penny retrieve the gem from a skull before the cavern it's in gets flooded. Madame Medusa then hides the gem inside Penny's teddy bear. Kirika steals the diamond from Madame Medusa and places it in her pocket. At the end of the film, the Devil's Eye is donated to the Smithsonian Institute.