A leyak is in Balinese lore, a sorcerer who has the ability to shape shift into a Demon, causing death and destruction to people, animals, and crops. The leyak also is the cause of all bad events and misfortunes. While the sorcerer sleeps, the leyak flies in the night skies in the form of a mysterious light, a monkey, or a bird. If the leyak is destroyed, its human form dies instantly along with it. A leyak can remain disguised to fellow human beings indefinitely. Usually, it is unmasked only when it is killed in its shape-shifted form.