Rāhu

Rāhu -(Tib: kyab jug )
Rahula is a supernatural being of the Tibetan buddhist tradition, particularly the Nyingma lineage. He is depicted as dark blue ans one of his nine heads is that of a raven. He has a face in his belly the mouth of which swallows up the moon or sun during eclipses. He is master of the nine planets and the god of solar and lunar eclipses. He is a wrathful dregs-pa according to the Nyingmapas; one of eight highest protector deities and who rules over a class of gza demons.During the time of the influence of these malevolent beings, one would not normally start new projects. But since Rahula is an emanation of Vajrapani, a companion to Chenrezi, and the bodhisattva who embodies all the power of all the Buddhas, the evil influences are controlled
==The Hindu legend==
Rahu is depicted as a naga king, a deity of the earth and/or of water whose tail and lower torso are those of a serpent. Rahu is a rakshasa, a trickster-deity sometimes described as a demon or ogre. However, this category of being also includes some anti-gods ("titans") that can function as protectors. The recurrence of eclipses in a regular pattern is explained by one Hindu myth which tells how Rahu stole Amrita, the Water of Life [Nectar of Immortality] from the gods, but the sun and moon were witnesses. Lord Vishnu punished the thief, Rahu, by cutting off 2 of his 4 arms and Rahu, in his anger, stalks back and forth across the heavens from the moon to the sun. 
The presence of Rahu and his other half, Ketu, in the heavens comes only because ... just as he was getting what he sought, he was slain, and henceforth having gotten a taste of the eternalizing (within this realm) Soma Drink, is now living on like a God ... . Ketu is the dead half of his body. Rahu is the ever-living head. One alive, one dead. [Rahu, the head, is the moon's northern node; Ketu, the headless body, is the other node.] 
==The Tibetan Buddhist version==
The Chakdor Legend:
All the Buddhas gather on top of Mount Meru to consider how to obtain the elixir of life, Dutsi. They are seeking an antidote to Hala, the source of human illness that the demons have in their possession. They churn the ocean and procure the dutsi which they entrust to the protector, Vajrapani. However, the monster Rahu manages to steal it. He drinks it down, and then urinates it back into the vessel that it had been put into by the Buddhas. Vajrapani realizes what has happened and sets out to kill Rahu. He questions the Sun as to the demon's whereabouts, but the Sun fears retaliation from Rahu. The Moon felt no different, but still was willing to help the cause, and reveals where Rahu is hiding. Slain by Vajrapani at last, the rakshasa comes back to life because he had drunk the dutsi or, in Sanskrit, amrita. Now Vajrapani has to take his punishment; he is made to drink the urine. He conceives an even greater rage against Rahu and all demons, and slays him over and over again. Wherever the blood of Rahu dripped onto the surface of this earth, it caused to spring up all manner of medicinal plants
Category:Buddhist deities, bodhisattvas, and demons
Category:Dharmapalas
et:Rāhu (budism)
pl:Rahu (demon)