The elephant of Indravarma of the Malavas.
Drona failed to win the war for the Kauravas. He had once announced that he would lay down his arms if his son, Ashwatthaman, fell. The Pandavas brought this about with a trick. Bhima killed an elephant named Ashwatthaman and Krishna spread the news that Ashwatthaman had fallen. Drona asked Yudhishthira if that was true. Yudhishthira confirmed: ‚Yes, Ashwatthaman (‚the elephant‘ he whispered to himself) is dead.‘ Drona put down his arms. He closed his eyes and immersed himself in meditation. Drishtadyumna beheaded Drona.
Ashwatthaman is included in this story about Drona