Nahush was a pious King.

According to an Indian mythological story, when Indra, the lord of paradise, slew the demon Vritra (who was a Brahman by birth) he incurred the sin of having killed a Brahman and out of shame hid himself in the Mansarovar lake. Finding themselves without a king the gods installed King Nahush on the throne of Indra and poroclaimed him as their ruler.

Nahush once beheld Indra's wife and, enamoured of her beauty, longed to take her to wife. Shachi, who was noted for her fidelity to her husband, did not approve of Nahush' overtures and approached the sage Brihaspati, the preceptor of gods for protection. The gods and sages thereupon expostulated with Nahush and tried to dissuade him but in vain.

However, as per the advice of Brihaspati, Shachi then offered to accept Nahush as her husband if the latter rode to her on a palanquin carried by sages. Nahush, who was blinded by passion and was bent on having her as his wife at all costs, gladly agreed and prevailed on the sages to carry him on their shoulders. As the sages, who got tired very soon, were proceeding rather slowly, Nahush spurred them on and while doing so kicked the sage Agastya and the latter pronounced a curse upon him that he should take the form of a python.