As Beowulf fought with Grendel's mother, her winding and unwinding arms arms that look like sinewy, swollen snakes, were no match for the sword of the giants. The monster managed only the merest tiny little cough.
After killing Grendel's mother, Beowulf encounters Grendel's dead body and decapitates him. Taking the head with him as a prize.
As he exited the lake filled with battle sweat, Beowulf carries Grendel's head to gloat and be praised.
That night, the kingdom celebrated in honor of the mightiest man on Earth, his last battle, or so he thought.