The thunder was created by Indra in the days of yore in order to kill Vitra, (but) it broke into a thousand pieces when hurled on Vitra's head.
पुरा कृतं महेन्द्रस्य वज्रं वृत्रनिबर्हणम्। दशधा शतधा चैव तच्छीर्णं वृत्रमूर्धनि॥