Kadru's curse upon her sons and the Sarpa satra

Parikshit, the grandson of Arjuna, was killed by the naga Takshaka. His son Janamejaya was filled with rage when he came to know and he decided to conduct a massive sarpa satra that would destroy all the snakes.

The yaga began and the mantras chanted began to pull all the snakes inexorably right into the flames. Crores of snakes were burned to ashes as the yaga proceeded. A terrified Takshaka flew to this friend, Indra, and sought shelter. Indra promised that he would not be touched as long as he stayed there under Indra’s protection.

However, upon Earth, the naga Vasuki was terribly worried as he could see his kith and kin being destroyed by the thousands. He was himself barely avoiding being pulled into the agni.

He knew that this was Mother Kadru’s curse coming to fruition. A long time ago, Kadru had a bet with her sister and co-wife, Vinata, that the celestial horse Uchaisravas had a black tail. Vinata had correctly held that the horse was pure white all over. Not wanting to lose, Kadru had instructed her children, the snakes, to turn black and cover Uchaisravas’ tail so she would not lose the bet and become Vinata’s slave, as per the agreement. When the snakes refused, Kadru cursed them to be burned, years hence, in the fire of Janamejaya’s sarpa yaga.

This curse was now coming true. Vasuki recalled the words of Brahmadeva when he had approached him after helping the Devas with samudra manthan. Brahmadev had promised Vasuki that the curse could be nullified and the deaths of the snakes stopped by his sister’s son. If his (Vasuki’s) sister Jaratkaru married someone with the same name as herself and had a son, this son would be able to stop the sarpa yaga of Janamejaya.

This son was the rishi Astika, who finally did stop the sarpa yaga just as the mantras pulled Takshaka as well as Indra, who was protecting him, towards the fire.