Krishna overcoming the serpent Kaliya, from a manuscript of the Bhagavata Purana (Ancient Tales of the Lord Vishnu)

Krishna arrives with Balarama and their friends at the Yamuna River only to find the waters poisoned by the serpent Kaliya.

Within its bed was the fearful pool of the serpent Kaliya, boiling with the fires of poison from the fumes of which large trees on the bank were blighted, and by whose waters, when raised by a gale into the air, birds were scorched. Krishna decided to dislodge Kaliya for it was the purpose of his descent upon earth to reduce to subjection all such violators of law. Laying hold of the middle hood of Kaliya with both his hands, he bent it down, and set his foot upon it, and danced upon it in triumph. Trampled upon by his feet, as they changed position in the dance, the snake fainted, and vomited forth much blood. Finding their serpent-husband collapsing under the infinite weight of Krishna its distressed wives folded their palms and sought asylum in Krishna who affords protection to all.
 From the Bhagavata Purana