According to Hindu tradition, when Lord Krishna was a child, he was playing in the river Yamuna and while playing with a ball got caught on the branches of a tree. When Lord Krishna tried to catch the ball, he was bitten by a snake named Kaliya. Krishna fought bravely and after realizing that Krishna was no ordinary child. The serpent Kaliya begged him not to harm him. Nag Panchmi is celebrated in honor of Krishna's victory in saving humanity from the perils of Kaliya. Kaliya is the deadliest snake, Lord Krishna saved the snake by taking a promise from him that he would not harm people from now on.