Which avatar of Vishnu has the head of a lion?

Narasimha, (Sanskrit: “Man-Lion”) one of the 10 avatars (incarnations) of the Hindu god Vishnu. The demon Hiranyakashipu—twin brother of Hiranyaksha, the demon overthrown by Vishnu in his previous incarnation as Varaha—obtained a boon from the god Brahma that he could not be killed by human or animal, from inside or outside, by day or by night, and that no weapon could harm him. 

Narasimha is one of the major deity of Hare Krishna (ISKCON) devotees. Narasimha legends are revered in Vaikhanasas, Sri Vaishnavism, Madhwa Brahmins but he is a popular deity beyond these Vaishnava traditions such as in Shaivism. He is celebrated in many regional Hindu temples, texts, performance arts and festivals such as Holika prior to the Hindu spring festival of colors called Holi. The earliest representation, dating back to the 4th-century CE, of Narasimha is from Kondamotu in Coastal Andhra. Other older known artworks of Narasimha have been found at several sites across Uttar Pradesh and Andhra Pradesh, such as at the Mathura archaeological site. These have been variously dated between 2nd and 4th-century CE.

 

Picture Credit : Google