SB 8.11.28
sa tenaivasta-dharena
sirasi bala-pakayoh
jñatinam pasyatam rajañ
jahara janayan bhayam
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
O King Pariksit, King Indra used his thunderbolt to cut off the heads of both Bala and Paka in the presence of all their relatives and followers. In this way he created a very fearful atmosphere on the battlefield.