SB 4.19.17
so ’svam rupam ca tad dhitva
tasma antarhitah svarat
virah sva-pasum adaya
pitur yajñam upeyivan
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
When Indra saw that the son of Prthu was chasing him, he immediately abandoned his false dress and left the horse. Indeed, he disappeared from that very spot, and the great hero, the son of Maharaja Prthu, returned the horse to his father’s sacrificial arena.