Srimad Bhagavatam Canto 10, Chapter 66, Text 40

SB 10.66.40

krtyanalah pratihatah sa rathanga-paner
 astraujasa sa nrpa bhagna-mukho nivrttah
varanasim parisametya sudaksinam tam
 sartvig-janam samadahat sva-krto ’bhicarah
Frustrated by the power of Lord Krsna’s weapon, O King, the fiery creature produced by black magic turned his face away and retreated. Created for violence, the demon then returned to Varanasi, where he surrounded the city and then burned Sudaksina and his priests to death, even though Sudaksina was his creator.
Srila Prabhupada comments as follows: “Having failed to set fire to Dvaraka, the fiery demon went back to Varanasi, the kingdom of Kasiraja. As a result of his return, all the priests who had helped instruct the black art of mantras, along with their employer, Sudaksina, were burned into ashes by the glaring effulgence of the fiery demon. According to the methods of black-art mantras instructed in the tantra, if the mantra fails to kill the enemy, then, because it must kill someone, it kills the original creator. Sudaksina was the originator, and the priests assisted him; therefore all of them were burned to ashes. This is the way of the demons: the demons create something to kill God, but by the same weapon the demons themselves are killed.”
Srimad Bhagavatam Canto 10, Chapter 66, Text 39
Srimad Bhagavatam Canto 10, Chapter 66, Text 41