Musannaf Ibn Abi Shayba 16:287

Abu Bakr narrated to us, he said: Hisham narrated to us, from Husayn, who said: Khalid ibn al-Walid arrived here, and there was a man from the people of Persia [with a spear] against them, called Hazar Mard. He said: They mentioned his immense stature and his bravery. He said: So Khalid ibn al-Walid killed him, then he called for his lunch and ate while reclining upon his corpse, meaning his body.