This chapter describes in detail Krishna's pastime of killing Aghasura.

One day Krishna wanted to enjoy a picnic lunch within the forest, and therefore He went out early into the forest with the other cowherd boys, accompanied by their respective groups of calves. While they were enjoying their picnic, Aghasura, the younger brother of Putana and Bakasura, appeared there, desiring to kill Krishna and His companions. The demon, who had been sent by Kamsa, assumed the form of a python, expanding himself to a length of eight miles and the height of a mountain, his mouth seeming to extend from the surface of the earth to the heavenly planets. Having assumed this feature, Aghasura lay on the road. Krishna's friends, the cowherd boys, thought that the demon's form was one of the beautiful spots of Vrindavana. Thus they wanted to enter within the mouth of this gigantic python. The gigantic figure of the python became a subject for their sporting pleasure, and they began to laugh, confident that even if this figure were dangerous, Krishna was there to protect them. In this way, they proceeded toward the mouth of the gigantic figure.

Krishna knew everything about Aghasura, and therefore He wanted to forbid His friends to enter the demon's mouth, but in the meantime all the cowherd boys, along with their groups of calves, entered the mouth of that gigantic figure. Krishna was waiting outside, and Aghasura was waiting for Krishna, thinking that as soon as Krishna entered he would close his mouth so that everyone would die. While waiting for Krishna, he refrained from swallowing the boys. In the meantime, Krishna was thinking of how to save the boys and kill Aghasura. Thus He entered the mouth of the gigantic asura, and when He was within the demon's mouth along with His friends, He expanded His body to such an extent that the asura suffocated and died. After this, Krishna, by casting His nectarean glance upon His friends, brought them back to life, and with pleasure they all came out unhurt. Thus Krishna encouraged all the demigods, and they expressed their pleasure and happiness. For a crooked, sinful person there is no scope for sayujya-mukti, or becoming one with the effulgence of Krishna, but because the Supreme Personality of Godhead entered the body of Aghasura, by His touch this demon got the opportunity to merge into the existence of the Brahman effulgence and thus attain sayujya-mukti.

When this pastime was performed, Krishna was only five years old. One year later, when He was six years old and He stepped into the pauganda age, this pastime was disclosed to the inhabitants of Vraja. Parikshit Maharaja inquired, "Why is it that this pastime was disclosed only after one year and yet the inhabitants of Vraja thought that it had been performed that very day?" With this question, the Twelfth Chapter ends.