​Manasa (Mansa Devi) is a Hindu folk goddess of snakes, worshipped mainly in Bengal and other parts of North and northeastern India, chiefly for the prevention and cure of snakebite and also for fertility and prosperity. Manasa is the sister of Vasuki, king of Nāgas (snakes) and wife of sage Jagatkāru (Jaratkāru).

She is also known as Vishahara (the destroyer of poison), Jagadgaurī, Nityā (eternal) and Padmavati. Her myths emphasize her bad temper and unhappiness, due to rejection by her father Shiva and her husband, and the hatred of her stepmother, Chandi (Shiva's wife, identified with Parvati in this context). In some scriptures, sage Kashyapa is considered to be her father, rather than Shiva. Manasa is depicted as kind to her devotees, but harsh to people who refused to worship her.

Denied full godhead by her mixed parentage, Manasa’s aim was to fully establish her authority as a goddess and to acquire steadfast human devotees. Accompanied by her adviser, Neto, Manasa descended to earth to obtain human devotees. She was initially mocked by the people but then Manasa forced them to worship her by raining calamity on those who denied her power.

She managed to convert people from different walks of life, including the Muslim ruler Hasan, but failed to convert Chand Sadagar, an ardent Shiva and Chandi devotee. In attempting to convert him, Manasa killed Chand's six sons and left him bankrupt. She also killed Lakhindar, Chand's youngest son, on his wedding night. Chand's wife and widowed daughter-in-law tried to coax him to worship Manasa. At last, he yielded by offering a flower to the goddess with his left hand without even looking at her. This gesture made Manasa so happy that she resurrected all of Chand's sons and restored his fame and fortunes. The Mangal kavyas say that after this, the worship of Manasa was popular forever more — at Society For The Protection and Promotion of Polytheism.