Explanation : Ashvathama, Drona's son, was immortal. There was an elephant in the war by the name of Ashvathama. Bheema slew this elephant and went around the battlefield proclaiming that he had slain Ashvathama. When Drona heard this, he went to Yudhistira and asked him if what Bheema had declared was true. Yudhistira said that Ashvathama had been killed, but if it was an elephant or man, he did not know. But Drona did not hear the last part and in his grief, laid down his weapons and started meditating. Dhristadyumna, sensing the opportunity, slew Drona.