Rahu and Ketu, treated in Hindu astronomy and astrology as shadow entities responsible for solar and lunar eclipses, share an origin story tied directly to the aftermath of the Samudra Manthan.
A line meant to be uncrossed
When Vishnu, in the form of Mohini, began distributing the nectar of immortality obtained from the churned ocean, he seated the devas and asuras in separate rows to ensure only the devas received it. An asura named Svarbhanu, disguising himself as a deva, slipped into the deva line undetected and managed to drink a portion of the nectar before being discovered.
Caught by the sun and moon
Surya and Chandra, the sun and moon gods, noticed the deception and alerted Vishnu, who immediately hurled his Sudarshana Chakra and severed the impostor’s head – but not before the nectar had already passed his throat, making him immortal despite the beheading.
Two beings from one punishment
Because the nectar had granted immortality before the strike landed, both the severed head and the body survived as separate entities: the head became Rahu, and the body became Ketu. Both were placed among the celestial bodies, and both are said to hold a lasting grudge against Surya and Chandra for exposing them – periodically swallowing one or the other, an act that, according to this mythology, produces the eclipses still observed today, always temporary since Rahu and Ketu have no throat or body respectively to permanently hold what they swallow.