One day the cowherd boys were playing their games, such as imitating peacocks and running after birds' shadows on the ground, when they came upon a mountain cave. This was actually a demon-brother of Putana's, who had expanded himself into an eight-mile long snake to kill the boys. The opening to the cave was his mouth. The boys felt a hot wind blowing that smelled like fish, or the serpent's intestines.
The scriptures say that when the boys walked into the cave Krishna became momentarily aggrieved because He knew it was one of Kamsa's tricks. He considered for a moment, then decided to enter the cave Himself. Demons all over the world became joyful when Krishna went inside. The demigods, who had been hiding among the clouds to see what would happen, became distressed. For a time it seemed as if the snake-demon had killed Krishna, but when Krishna heard the demigods' pleas He grew larger and choked the demon to death. Aghasura's life air burst through a hole in his skull and waited there for Krishna to come out, then it merged into His body. Krishna showed His benevolent nature by rescuing His friends and giving liberation to Aghasura.