In Hinduism, Samudra manthan or The churning of the ocean of milk is one of the most famous episodes in the Puranas and is celebrated in a major way every twelve years in the festival known as Kumbha Mela. The story appears in the Srimad Bhagavatam, the Mahabharata and the Vishnu Purana.
Samudra manthan is also known as —
Samudra manthanam — Manthanam is the Sanskrit equivalent of Manthan meaning 'to churn'.
Sagar manthan — Sagar is another word for Samudra, both meaning an ocean or large water body.
Ksheersagar manthan — Ksheersagar literally means the ocean of milk. Ksheersagar = Ksheer (milk) + Sagar (ocean).
The story of Samudra manthan
The story begins with Indra, the king of gods, riding his elephant. He came upon a sage named Durvasa. The sage decided to honour Indra by giving him a scented garland. Indra took the garland, but placed it on the forehead of his elephant. The elephant was irritated by the scent and threw the garland off, trampling on it. The angry sage cursed Indra and the Adityas(gods) to lose all their wealth; and be deprived of Laxmi, the goddess of wealth and prosperity. Indra was thus immediately dispossessed of all his wealth and treasures.
Appeal to Brahma
Indra then approached Brahma, the creator, to help him regain his treasures who suggested him to churn the Ocean of Milk in order to regain his treasures and obtain the Nectar of Immortality. However, such a stupendous task could not be performed by the Adityas (gods) alone, so they sought the help of their enemies, the Asuras, with the understanding that the Asuras would be allowed to partake a portion of the Amrita (divine nectar of immortality).
Churning the Milky Ocean
The ocean was churned by using the Mount Mandara as the pole and the King of Snakes, Vasuki, as the rope. The gods held the tail of the snake while the demons (Asuras) held the head end of the snake and they pulled on it alternately causing the mountain to rotate which in turn churned the ocean. However, once the mountain was placed on the ocean, it began to sink. Then came Vishnu in his second incarnation, in the form of a turtle Kurma, and supported the mountain on his shell back.
As the ocean was churned, a deadly poison known as Halahala emerged. This poison threatened to suffocate all living things. In response to various prayers, Shiva drank the poison; his wife Parvati, alarmed, stopped it in his throat with her hands. This caused the throat to turn blue. Due to this, he is called Nīlakantha (nīla = "blue", kantha = "throat"). Then, various treasures (ratnas) emerged from the ocean of milk. The 14 Ratnas were:
Sura, goddess and creator of alcohol
Apsarases, various divine nymphs like Rambha, Menaka
Kaustubha, the most valuable jewel in the world
Uchhaishravas, the divine 7-headed horse
Kalpavriksha, the wish-granting tree
Kamadhenu, the first cow and mother of all other cows
Airavata, the elephant of Indra
Lakshmi, the Goddess of Fortune and Wealth
Parijat, the divine tree
Halahala the deadly poison
Chandra, the moon
Dhanvantari, the doctor
The nectar of immortality
Finally, Dhanvantari, the Heavenly Physician, emerged with a pot containing amrita, the heavenly nectar of immortality. As the Asuras rushed to take the nectar, the frightened Adityas appealed to Vishnu, who then took the form of Mohini. As a beautiful and enchanting damsel, Mohini distracted the Asuras, took the amrita, and distributed it amongst the Adityas who drank it. One Asura, Rahu, disguised himself as an Aditya, and drank some Nectar. Due to their luminous nature the Sun God Surya and the Moon God Chandra noticed the switching of sides. They informed Mohini. But before the Nectar could pass his throat, Mohini cut off his head with Her divine discus, the Sudarshana Chakra. The head, due to its contact with the amrita, remained immortal. To gain revenge on Sun and Moon for exposing this - 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.
The story ends with the rejuvenated Adityas defeating the Asuras.
~ from Wikipedia