In the town of Gokul, the citizens noticed strange events happening around them. The elders decided it was best to leave Gokul and move to Vrindavan, where the grazing fields were abundant. The residents of Vrindavan also observed the supernatural powers of the boy Krishna. One after the other, Krishna killed Vatsasura, Bakasura, and Aghasura. As each demon was defeated, an effulgent light came out of its body and entered Sri Krishna’s body.
Aghasura was particularly powerful, determined to take revenge for his siblings' deaths. He transformed himself into an immense python, lay down on the path, and opened his huge mouth. The cowherd boys saw the mouth of the python as a cave and entered it. Krishna realized that it was an asura, but it was too late. He also entered the mouth of the asura, but he began to take a huge form, thus obstructing the air passage of the demon. When Aghasura could not get his breath, he began to roll around in agony. At last, his head burst, and he died. Krishna then came out of the demon with his friends.
After killing Aghasura, Krishna, Balarama, and their cowherd friends went to eat their food on the banks of the Yamuna River. The cowherd boys appeared, sitting around Krishna, just like the petals of a lotus grow around its centre. That day, on the bank of the Yamuna, the cowherd boys indulged in a great feast with Krishna sitting in the middle.
Brahma and other devas watched this scene from above. Brahma had doubts about Krishna's true identity and wondered if he was really Sri Vishnu, who had come to earth to relieve it of its burden. Brahma then lured the calves away to a distant wood. The cowherd boys noticed that the calves were gone, and Krishna reassured them, saying that he would check on them. While Krishna was searching for the calves, Brahma kidnapped the cowherd boys and hid them in a cave.
Krishna could not find the calves anywhere and returned to the bank of the Yamuna. He searched the entire forest but could not find the cowherd boys. Then he remembered who he was and realized that Brahma had played a trick on him. Krishna transformed himself into all the cowherd boys and the calves. He became each and every boy and each and every calf, with whatever clothes each was wearing, with whatever instrument each was carrying, with whatever character, name, form, and age each had. In this way, Krishna proved the saying that "All this is Vishnu."
So all the 'Krishna-cowherd boys' and 'Krishna-calves' returned to the village, to their respective mothers and mother cows. The mothers were overjoyed, as Krishna had become their sons and calves. For a full year, the Krishna-cowherd boys and Krishna-calves lived in Vraja, and no one suspected anything.
One year on earth is equal to just one moment of Brahma. When Brahma looked up after a moment, he was startled. He thought that the cowherd boys and calves were still asleep in the cave where he had hidden them. Yet, Krishna was playing with the same boys and calves. Brahma thought and thought, but he could not solve this riddle. Then he began to wonder, "Which ones are real, and which ones are unreal?" Brahma had tried to ensnare Krishna in Maya, but instead, he himself became ensnared. As Brahma looked at the scene with his mind in confusion, like he was under a spell, as he looked around and saw that the entire universe was filled with innumerable forms of Sri Krishna. Everywhere he looked, he saw only Krishna.
Finally, Brahma realized that he was witnessing the divine Leela, or the play of God, and that Sri Krishna was the Supreme Personality of Godhead Himself. He felt immense gratitude and awe towards the Lord, and his doubts and illusions were completely dispelled.
Brahma then offered his obeisances to Sri Krishna and praised Him with great devotion, acknowledging His supreme power and glory. He said, "O Lord, You are the source of all creation, maintenance, and destruction. You are the cause of all causes, and the ultimate goal of all beings. I am humbled by Your transcendental nature, and I offer myself to You in surrender."
Sri Krishna then revealed His original form as the two-armed cowherd boy, and smiled at Brahma with great affection. He said, "Brahma, I am pleased with your devotion and understanding. You have realized the truth of My nature and Leela. May you continue to serve and worship Me with love and devotion."
With these words, Sri Krishna disappeared from Brahma's sight, and Brahma returned to his abode, filled with wonder and awe. He realized that Sri Krishna was not just a boy, but the Supreme Lord who had descended on earth to perform His divine pastimes and bestow His mercy upon all living beings. From that day on, Brahma became a staunch devotee of Sri Krishna, and he sang His glories throughout the universe.