Hindu mythology contains a story about the churning of the Cosmic Ocean in
order to obtain Amrita(Ambrosia) - the nectar of immortal life. At the suggestion of Vishnu the gods, (devas)
and demons (asuras)
churn the primeval ocean in order to obtain Amrita which will
guarantee them immortality. To churn the ocean they used the Serpent King, Vasuki, for their
churning-string. For a churning pole they use Mount
Mandara placed on the back of a Great Tortoise - the Kurma Avatar of Vishnu.
As the gods and demons churned the sea, a terrible poison issued out of its
depths which enveloped the universe. The devas and asuras approach Shiva who took the
poison into his throat and swallowed it. Shocked by his act, Goddess Parvati
strangled his neck and hence managed to stop it in his neck and prevent it from
spreading. However, the poison was so potent that it changed the colour of his
neck to blue, thereby earning him the name of Neelakanta (blue-throated one).
When the Amrita finally emerged along with several other treasures the devas
and asuras fought over it. However Vishnu in the form of Mohini the
enchantress manages to lure the asuras into handing over the Amrita to her,
which she then distributes to the devas. Rahu, an asura,
disguises himself as a deva and tries to drink some Amrita himself. Surya (the sun-god)
(the moon-god) alert Vishnu to this deception. Vishnu then decapitates Rahu
just as he is about to swallow the nectar, leaving only his head immortal.
According to Bhagavata, outcome of the churning of Ksheerasagara is
Halahalam (terribly destructive poison), Amrita (nectar) with Dhanvantari
(physician of Gods), Lakshmi (Goddess of Riches), Jyestha (Goddess of Poverty),
Chandra (the Moon), a white elephant named Airavata, a horse named
Uchchaisrava, Kalpavriksha (the tree that yields whatever is desired).
The Churning of the Cosmic Ocean (the Milky Way) is told in several ancient
texts, notably in the Valmiki'sRamayana Canto 45  and
in the Mahabharata.