The proper home of Kāliya was Ramanaka Dwipa, but he had been driven away from there by fear of Garuda, the foe of all serpents. Garuda had been cursed by a yogi dwelling at Vrindavan so that he could not come to Vrindavan without meeting his death. Therefore Kāliya chose Vrindavan as his residence, knowing it was the only place where Garuda could not come.
Once Krishna and herdboys were playing ball, and while playing Krishna climbed up the Kadamba tree and hung over the river bank, the ball fell into the river and Krishna jumped after it. Kāliya rose up with his hundred and ten hoods vomiting poison and wrapped himself around Krishna's body. Krishna became so huge that Kāliya had to release him. So Krishna saved himself from every attack, and when he saw the Brij folk were so much afraid he suddenly sprang into Kāliya's head and assumed the weight of the whole universe, and danced on the naga's heads, beating time with his feet. Then Kāliya began to die. But then the naga's wives came and prayed to Krishna with joined palms, worshipping Krishna and praying for their husband.
Kāliya, recognizing the greatness of Krishna, surrendered, promising he would not harass anybody. So Krishna pardoned him and then let him go free to leave the river and go to Ramanaka Dwipa. Some identify it as Fiji.
blurb courtesy - Wikipedia