What two things does Beowulf take from the sea hag's cave?
After descending into the water, Beowulf returns from the cave of the sea hag (Grendel's mother) with the severed head of Grendel and the hilt of the sword he used to kill the hag and decapitate Grendel's body. Grendel's toxic blood melts the blade of the sword as he cuts off his head, so only the hilt remains. Beowulf and the thanes bear the trophies back to the hall, where Beowulf presents them to Hrothgar, saying:
Lo and behold! To you, son of Healfdene, lord of the Scyldings, have we heartily brought this booty from the lake; what you look upon here is a sign of victory!
Beowulf then related his deeds to the king and his followers, and assured them they they could safely rest in Heorot. He is acclaimed for his deeds, which was part of his motivation for returning with the trophies in the first place.