In Hindu tradition, Rahu is the severed head of an asura called Svarbhānu, that swallows the sun causing eclipses. He is depicted in art as a serpent with no body riding a chariot drawn by eight black horses. He is one of the navagraha (nine planets) in Vedic astrology and is paired with Ketu. The time of day considered to be under the influence of Rahu is called Rahu kala and is considered inauspicious. In Vedic astronomy, he is considered to be a rogue planet. He is also known as Bhayanaka.
He is mentioned explicitly in a pair of scriptures from the Samyutta Nikaya of the Pali Canon. In the Candima Sutta and the Suriya Sutta, he attacks Surya, the Sun deity and Chandra, the Moon deity before being compelled to release them by their recitation of a brief stanza conveying their reverence for the Buddha. The Buddha responds by enjoining him to release them, which Rahu does rather than have his “head split into seven pieces”. The verses recited by the two celestial deities and the Buddha have since been incorporated into Buddhist liturgy as protective verses recited by monks as prayers of protection.
