Zahhāk or Zahāk also known as Zahhak the Snake Shoulder is an evil figure in Persian mythology, evident in ancient Persian folklore as Azhi Dahāka, the name by which he also appears in the texts of the Avesta. In Middle Persian, he is called Dahāg or Bēvar Asp the latter meaning "he who has 10,000 horses". In Zoroastrianism, Zahhak is considered the son of Ahriman, the foe of Ahura Mazda. In the Shāhnāmah of Ferdowsi, Zahhāk is the son of a ruler named Merdās.