Vinata bore a winged son. He was none other than the King of birds, Garuda. The snakes would task Garuda with chores, and Vinata would ask her son to duly oblige. Garuda wondered why he had to bide by the orders of the snakes. He soon learnt that it was due to a lost bet.
Wanting to be free, Garuda went to the snakes and put forth his request. The snakes agreed, provided Garuda fetched them a pot of divine nectar in return.
Garuda then embarked on an adventurous quest. As per the advise of his mother, he first reached an island and fed on Nishadas (a tribe of fishermen) living in that place (Garuda did not have any food sanctioned at that time by the Creator).
He then preyed upon a vengeful and monstrous pair of an elephant and a tortoise. In the process, he also saved a group of Valakhilya rishis falling upside down from the branches of a huge banyan tree. During this time, he met his father Kashyapa who was then meditating in the woods and received his blessings .
Later, he proceeded to claim the nectar of immortality from the celestials. A fierce battle ensued, where Garuda defeated Indra, Sadhyas, Gandharvas, Vasus, Rudras, Aswin twins and Yakshas. Garuda then doused a huge column of fire on his path, before entering the place where the divine nectar was guarded.
The nectar was guarded by a spinning wheel-like device intended to cut any intruder to pieces. Garuda assumed a miniature form and entered the device. He then came across two fiery snakes, whom he cut into pieces and successfully claimed the pot of elixir.
Garuda, without consuming even a drop of nectar, rushed back to the abode of the Nagas. Observing his selfless act, Vishnu became appeased. He appeared before the bird and offered him a boon of his choice. Garuda asked for immortality and also an eternal position above the Lord (in his flag). Vishnu agreed. Garuda too offered Vishnu a boon in return, and the Lord hence called for Garuda to become his vehicle. Garuda acquiesced, and subsequently took to the skies.
Indra, observing Garuda flying with great speed, hurled his Vajra weapon towards the bird. Garuda, despite being struck with the weapon, smiled and told Indra in polite words, "O King of the Devas. I respect the rishi (Dadichi) from whose backbone this Vajra weapon was made; I respect you too. To honour this, I will shed a single feather. But know that I have not felt any pain due to this weapon". Saying this Garuda dropped a single feather. Beholding this act and seeing the beautiful feather, all the creatures became excited, and said, "Let this bird of beautiful feather be called 'Suparna' (one of fair feathers)".
Indra, realizing the bird's greatness, sought Garuda's friendship and asked him not to share the nectar with anyone. Garuda replied, "O King, I am taking this to my destination for a reason. Once I deliver this, you can swiftly come and take this away."
Indra agreed, and offered Garuda a boon. Remembering the deceitful acts of the snakes, Garuda said, "Let the snakes become my food". Indra said "So be it".
Upon reaching the destination, Garuda placed the nectar on kusa (darbha) grass. He told the snakes to take their purifying bath & auspicious rites before consuming the nectar. He also asked them to liberate him. The snakes agreed. When they stepped away for their bath, Indra swiftly took back the pot of nectar.
The snakes came back and saw the pot missing. Thinking that drops of nectar may have come into contact with the kusa grass, they started licking the grass. The sharpness of the blades of grass cut their tongues due to which the organ acquired a forked shape. In addition, due to the contact with the divine nectar, the kusa grass became sacred from that time.