saḥ - he (Indra); tena - by that; eva - indeed; aṣṭa-dhāreṇa - by the thunderbolt; śirasī - the two heads; bala-pākayoḥ - of the two demons known as Bala and Pāka; jñātīnām paśyatām - while their relatives and soldiers were watching; rājan - O King; jahāra - (Indra) cut off; janayan - creating; bhayam - fear (among them).

O King Parīkṣit, King Indra used his thunderbolt to cut off the heads of both Bala and Pāka in the presence of all their relatives and followers. In this way he created a very fearful atmosphere on the battlefield.