SB 6.9.54
yusmabhyam yacito ’svibhyam
dharma-jño ’ngani dasyati
tatas tair ayudha-srestho
visvakarma-vinirmitah
yena vrtra-siro harta
mat-teja-upabrmhitah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
When the Asvini-kumaras beg for Dadhyañca’s body on your behalf, he will surely give it because of affection. Do not doubt this, for Dadhyañca is very experienced in religious understanding. When Dadhyañca awards you his body, Visvakarma will prepare a thunderbolt from his bones. This thunderbolt will certainly kill Vrtrasura because it will be invested with My power.