Balarama and Krishna assumed the role of cowherds and roamed about grazing calves in the woods. When they reach the vicinity of a pond, they halted to provide the cowherds and the calves water to drink. But they were frightened when they saw a monstrous creature, Baka, a demon in the form of a heron. Approaching Krishna, the monster Bakasura swiftly swallowed Krishna. Krishna became hot and burned the root of Bakasura's palate, that the demon, unable to bear the heat, disgorged him. Enraged, he rushed towards Krishna with his bills open to kill him. Krishna seized both halves of the bill in his hands and tore him apart like a blade of grass, as Balarama and the rest of the cowherds looked on.
One early morning, Krishna wakes up the cowherd boys with the charming sound of his horn. With his companions all equipped with slings, canes, horns, flutes and meals for the noon, Krishna set forth from Vraja. The team of cowherds herded their own calves along with the many calves of Krishna. Besides adorning themselves with glass beads, gunja seeds, gems and gold, they also decked themselves with fruits, tender leaves, flowers, peacock feathers and minerals. They teased other cowherd boys by hiding their slings etc., and returned it to them laughingly when they were annoyed. When Krishna went away to a distance to appreciate the sylvan beauty, the boys vied with one another ('me first, me first!') in touching him first. They felt delighted to embrace him. Some played the flute, some blew their horns, some sang to the humming of the bees, while some returned the sweet notes of the cuckoos.
Enter Aghasura, a mighty demon sent by Kamsa, who disliked the sportful behaviour of Krishna and his friends. He was the brother of Putana (Baki) and Baka. He vowed to despatch the cowherds along with Krishna, which he thought, would amount to destroying the whole of Vraja itself.
He assumed a monstrous form of a Boa Constrictor and lay down across the path, keeping his mouth wide open, as if to devour the entire group. Perceiving the corners of his mouth as caverns, the fangs resembling mountain peaks, interiors of the mouth covered with darkness, tongue as a broad road, the cowherds admired it to be a beautiful landscape of Vrindavana.
"Friends, does it not look like the mouth of a serpent meant to devour us?"
"Will it gulp us down when we have found out way into it? If so, it will also perish like the heron in the hands of Krishna." Saying so, they looked at the magnetic face of Krishna and went on, loudly laughing and clapping their hands. The serpent, though real, appeared to them to be fictitious. Krishna makes up his mind to restrain them. The children, along with their calves, made their way into the bowels of the demon, who did not devour them immediately, but waited for Krishna to enter too. Krishna perceives them to have become fodder for the gastric fire of Aghasura.
Krishna enters the mouth of the demon. He grew at great speed, in the throat of the monster, who was eager to pulverize him along with the other cowherds and calves. The demon's throat completely choked. The vital air pent up and spread through the internal organs of the monster, forced it way out splitting the crown of his head. All his senses also departed through that very passage. Krishna revived the children and calves and came out of the monster's mouth. A lustrous column of light arose from the robust body of the serpent, waited awhile for Krishna to make an exit, then entered him. Krishna was five at that time.
The astonished cowherds recounted joyfully the story of the killing of Aghasura, when Krishna was six, a year later.
Parikshit, listening to the narration attentively, questions Sage Shukha: "How could an act done in a distant time be conceived as having taken place at a present time, O holy one? The cowherds relate the story in his sixth year, what happened in his fifth year -- we are curious to know..."
Sage Shuka, robbed of all his senses by Krishna's nectar-like story, recovered his consciousness of the outer world with difficulty and answers Parikshit's question.