Krishna and Kaliya

During the Dvapara-yuga, the third-quarter of the world cycle, the serpent king Kaliya poisoned river Yamuna. Lord Krishna, the eighth incarnation (avatar) of Vishnu, was a young boy in Mathura and decided to right this evil. One day while playing on the banks of the river Yamuna, he jumped into the deepest part of the river where Kaliya was known to live and was immediately engulfed in Kaliya's coils. Krishna with a burst of divine power suddenly threw off Kaliya's coils. He then began to dance on the serpent's head, breaking the serpent's bones and will with every graceful dance step.

Kaliya's serpent-queens begged Krishna for his life. Kaliya himself lifted his broken head with the plea that he had only acted "according to his nature." With the acknowledgement that both good and evil are manifestations of the supreme Lord, Krishna spared Kaliya's life and bid him to reside henceforth only in the depths of the ocean.