After his defeat, Grendel fled back to his lair in the Lake of Monsters and died, but he was not alone there. His mother was furious about her son's death and wanted vengeance against the ones who killed him. So she invaded Herot and killed more men, one being one of King Hrothgar's closest friends, and took Grendel's arm. She then retreated back to her lair. Beowulf, angry with his trophy being stolen and seeing another way to prove himself in battle, went off to face her. He arrived at the Lake of Monsters with his men and jumped in. He started sinking to the bottom until Grendel's Mother attacked him, pulling him down to a battle-arena like area. Once there, Beowulf tried using his weapons this time to fight her but they did almost nothing to her, breaking apart. Now she was on the attack and Beowulf could not over-power her. She was going to kill him with her dagger but Beowulf saw his way out. He had spotted a huge sword made by giants and enchanted with their magic and he went right to it. He desperately lifted the heavy sword, going beyond normal human limits and swung with all his might, cutting off her head. He then found the dead Grendel and received another trophy form him, his head.