Hrunting was the magical sword given to Beowulf by Unferth in the ancient Old English epic. Beowulf used it in battle against Grendel's mother. The sword possessed great power and never failed anyone who used it, however when Beowulf descended to the bottom of the lake where Grendel's mother dwelt, the sword lost its power and the Hrunting was ineffective against the creature. Beowulf instead searched the monster's lair and found a sword which belonged to the Giants, which only he was strong enough to lift. Beowulf used this sword to kill and decapitate Grendel's mother, but the poisonous blood of the creature melted the Giants' sword like wax. Beowulf returned to the surface with the head of the monster as proof of his victory, and returned the Hrunting to Unferth.