King Nahusha performed hundred Ashwamedha yajnas and conquered all the kingdoms of earth and heaven. Then, Nahusha ordered Indra and his wife Shachi to become his servants.

Sachi, who was the queen of heaven, did not want to become a servant. She thought of a plan to punish Nahusha. She told Nahusha that she and Indra would become his servants only if he came on a palanquin carried by sages. She knew that sages are great people who would be insulted if Nahusha asked them to carry a palanquin. Proud Nahusha failed to realise this and ordered a few sages to carry his palanquin. Agastya was one of the sages carrying the palanquin tilted to one side. At this, Nahusha got angry and kicked him. Agastya felt insulted and cursed him to be born as a snake.