After Viśvarūpa was killed, his father, Tvaṣṭā, performed ritualistic ceremonies to kill Indra. He offered oblations in the sacrificial fire, saying, “O enemy of Indra, flourish to kill your enemy without delay.”
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
तासु बुद्बुदफेनाभ्यां दृष्टं तद्धरति क्षिपन् । हतपुत्रस्ततस्त्वष्टा जुहावेन्द्राय शत्रवे
tāsu budbudaphenābhyāṃ dṛṣṭaṃ taddharati kṣipan | hataputrastatastvaṣṭā juhāvendrāya śatrave
SB 6.9.11