Story of Rahu

Rahu is mentioned explicitly in a pair of scriptures from the Samyutta Nikaya of the Pali Canon. In the Candima Sutta and the Suriya Sutta, Rahu attacks Canda, the moon deity and Suriya, the sun 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 Rahu 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 (paritta) recited by monks as prayers of protection.

In Buddhism Rahu is one of the krodhadevatas (terror-inspiring gods).

Rahu is the ascending lunar node. In Hindu mythology, Rahu is a snake that swallows the sun or the moon causing eclipses. He is depicted in art as a dragon with no body riding a chariot drawn by eight black horses.

According to legend, during the Samudra manthan, the asura Rahu drank some of the divine nectar. But before the nectar could pass his throat, Mohini (the female avatar of Vishnu) cut off his head. The head, however, remained immortal. It is believed that this immortal head occasionally swallows the sun or the moon, causing eclipses. Then, the sun or moon passes through the opening at the neck, ending the eclipse.

There is another lila of Shiva and Rahu probably taken from Sivapuranam which is paraphrased by Joseph Campbell in his book The Power of Myth. Ganna Chakra also paraphrases this myth:

In the myth of the Daitya king Jalandhara, Jalandhara sends Rahu with a message to Shiva, demanding that he surrender Parvati to Jalandhara. Shiva was angry at this message, and this anger took the form of a terrible creature which sprang from his brow. It had the face of a lion, flaming eyes, a body which was dry and rough to the touch, long arms and a tongue which lolled with anger. The creature rushed at Rahu, ready to devour him. Shiva apparently said something along the lines of "we don't shoot the messenger" whereon the gana pleaded to Shiva that it was tortured by hunger. Shiva told the gana that if it was so hungry, it should eat its own flesh. This the gana did, until only its head was left. Shiva, pleased with such devotion, appointed the gana as his door-keeper, ordering that it create terror for all wicked people. Shiva also ordained that the gana be worshipped along with his worship, and gave it the name Kirtimukha.

In Thai legend, Rahu reappears as the younger brother of two men who are reincarnated as the sun and moon. Unhappy at being overshadowed, Rahu is constantly striving to dim their brilliance by swallowing them; and occasionally he is successful. In Chinese mythology, it is not a demon but a heavenly dog that bites into the sun.

In Thailand, devotees normally burn black joss sticks and present eight black offerings, including black-feathered chickens and coffee, to appease the dark angel in the run-up to the eclipse.