SB 6.10: The Battle Between the Demigods and Vṛtrāsura
As described in this chapter, after Indra obtained the body of Dadhīci, a thunderbolt was prepared from Dadhīci’s bones, and a fight took place between Vṛtrāsura and the demigods.
Following the order of the Supreme Personality of Godhead, the demigods approached Dadhīci Muni and begged for his body. Dadhīci Muni, just to hear from the demigods about the principles of religion, jokingly refused to relinquish his body, but for higher purposes he thereafter agreed to give it up, for after death the body is usually eaten by low animals like dogs and jackals. Dadhīci Muni first merged his gross body made of five elements into the original stock of five elements and then engaged his soul at the lotus feet of the Supreme Personality of Godhead. Thus he gave up his gross body. With the help of Viśvakarmā, the demigods then prepared a thunderbolt from Dadhīci’s bones. Armed with the thunderbolt weapon, they prepared themselves to fight and got up on the backs of elephants.
At the end of Satya-yuga and the beginning of Tretā-yuga, a great fight took place between the demigods and the asuras. Unable to tolerate the effulgence of the demigods, the asuras fled the battle, leaving Vṛtrāsura, their commander in chief, to fight for himself. Vṛtrāsura, however, seeing the demons fleeing, instructed them in the importance of fighting and dying in the battlefield. One who is victorious in battle gains material possessions, and one who dies in the battlefield attains a residence at once in the celestial heavens. In either way, the fighter benefits.