Mbh 7.91.1d

Then, king Srutayudha, deprived of his senses by wrath, took up another bow and struck the son of Vasava with nine arrows on the latter’s arms and chest. Then Arjuna, that chastiser of foes laughing the while, O Bharata, afflicted Srutayudha with many thousands of arrows. And that mighty car-warrior quickly slew also the latter’s steeds and charioteer. Endued with great strength the son of Pandu then pierced his foe with seventy arrows. Then the valiant king Srutayudha abandoning that steedless car, rushed in that encounter against Partha, uplifting his mace. The heroic king Srutayudha was the son of Varuna, having for his mother that mighty river of cool water called Parnasa. His mother, O king, had for the sake of her son, begged Varuna saying, “Let this my son become unslayable on earth.” Varuna, gratified (with her), had said, “I give him a boon highly beneficial to him, viz., a celestial weapon, by virtue of which this thy son will become unslayable on earth by foes. No man can have immortality. O foremost of rivers, every one who hath taken birth must inevitably die. This child, however, will always be invincible by foes in battle, through the power of this weapon. Therefore, let thy heart’s fever be dispelled.” Having said these words, Varuna gave him, with mantras, a mace. Obtaining that mace, Srutayudha became invincible on earth. Unto him, however, illustrious Lord of the waters again said, “This mace should not be hurled at one who is not engaged in fight. If hurled at such a person, it will come back and fall upon thyself. O illustrious child, (if so hurled) it will then course in an opposite direction and slay the person hurling it.” It would seem that when his hour came, Srutayudha disobeyed that injunction. With that hero-slaying mace he attacked Janardana. The valiant Krishna received that mace on one of his well-formed and stout shoulders. It failed to shake Sauri, like the wind failing to shake the Vindhya mountain.