What does Beowulf do after he kills Grendel's mother?

Although his sword, Hrunting, loaned to him by Unferth, fails to penetrate the mother's hide, Beowulf discovers a giant magic sword in the cave and is able to kill the mother with it. The sword melts to its hilt after Beowulf uses it to decapitate the corpse of Grendel, which lies nearby. read more

He takes Grendel's head and swims back to his men, four men carry it back. then beowulf began boasting about how he killed her. He then becomes king and lives peacefully for fifty more years. read more

Beowulf looks around and sees dead Grendel, so he immediately cuts monster's head off to present it to Hrothgar. As soon as he does that, the lake becomes stained with blood. The watchers ashore interprets this as a sign of Beowulf's death of the hands of Grendel's mother. read more