Vasuki (Sanskrit: वासुकी, वासव) is a naga, one of the serpents of Hindu and Buddhist mythology. He is a great king of the nagas and has a gem (Nagamani) on his head. Manasa, another naga, is his sister.Vasuki is Shiva (The destroyer) Snake. Vasuki is known in Chinese and Japanese mythology as being one of the "eight Great Naga Kings" (八大龍王 Hachi Ryuu-ou), amongst Nanda (Nagaraja), Upananda, Sagara (Shakara), Takshaka, Balavan, Anavatapta and Utpala.
Legends of Vasuki 
The most famous legend in Hinduism in which Vasuki took part was the incident of Samudra manthan, the churning of the ocean of milk. In this legend, Vasuki allowed the devas (gods) and the asuras (demons) to bind him to Mount Mandar and use him as their churning rope to extract the ambrosia of immortality from the ocean of milk.
In Buddhist mythology, Vasuki and the other Naga Kings appear in the audience for many of the Buddha's sermons. The duties of the naga kings included leading the nagas in protecting and worshiping the Buddha, as well as in protecting other enlightened beings.
Vasuki's Naga priest is Tatig Naga.
Vasuka (or Vasuki) is the name of a small Nair clan found near Mannarasala in Travancore. They claim that their ancestors were Nāga serpents spared when the Khandava Forest (modern day Delhi) was burnt and cleared by Krishna and the Pandavas to make way for their capital Indraprastha.