The Mahabharata/Book 1: Adi Parva…
“ The monster, in the meantime cut into pieces by the arrows of Arjuna, released the thigh of illustrious Drona and gave up the ghost. The son of Bharadwaja then addressed the illustrious and mighty car-warrior Arjuna and said, 'Accept, O thou of mighty arms, this very superior and irresistible weapon called Brahmasira with the methods of hurling and recalling it. Thou must not, however, ever use it against any human foe, for if hurled at any foe endued with inferior energy, it might burn the whole universe. ”
