On an occasion, Lord Krishna said, ‘O bull among the men! O King Yudhishthira! While you were living in the forest, once Ashwatthama came to Dwaraka and settled down there for a few days highly worshiped by the Vrishnis. One day he came to me all alone when I was on the sea coast without any companion of mine. Then smilingly addressing me said, ‘O Krishna! The weapon called Brahmashira which is worshiped by gods and Gandharvas is with me. O foremost one of Yadu’s race, in exchange for that divine weapon, give me your Discus which is capable of slaying all the foes in the battle.’
While he with joined hands persisted me repeatedly for my Discus, just to make him happy I said, ‘O mighty one! Gods, Danavas, Gandharvas, birds, snakes, and men assembled are not equal to even a hundredth part of my energy. I have this bow, shaft, mace, and Discus. I will give whichever of these you wish to have it from me. Without exchanging your weapon, you can have any among these weapons of mine whichever you think to be able to wield and use in battle.’
Smilingly I said, ‘Take it.’ Suddenly he got up and seized the Discus with his left hand. He tried his best but failed to even move the weapon from the spot on which it lay! Then he tried with his right hand. Having seized it very firmly and put forth all his strength, he still failed to either wield or move it. Thus, disgusted with his might, he stayed away.
Beholding his failure, I said, ‘O Ashwatthama, neither the wielder of Gandiva, the best among warriors having white steeds yoked unto his car, that hero who gratified Lord Shiva that invincible warrior Arjun or my son Pradyumna Or my son Samba had ever asked me that you have asked. Neither the great car-warriors of Vrishinis race nor the Andhakas ever asked me that which you have asked. However, O the son of the great preceptor, let me know with whom would you fight using this weapon?'
Hearing my words, Drona’s son said, ‘O Madhava! After offering worship to you, I intended to fight with you. By obtaining this weapon, I would become invincible in the three worlds. But what I have noticed that the weapon is unattainable by me, O Govinda. O Lord! This terrible weapon can only beheld by you, the foremost of all terrible persons! Nobody else is capable of possessing it!
Thus saying so, he left the place (Dwaraka) with so many valuables that I had gifted him. However, he was wicked-minded, cruel and a wretch! He still has that terrible weapon Brahmashira with him. He is wrathful, so can do anything.