As Beowulf gets ready to jump into the mysterious water to slay Grendels mother. He grabs his sword and jumps in, as everyone cheers him on.
as soon as he found her she gripped Beowulf in her room and brought him to a shaped like dome under the water which they fought
Beowulf found himself in a predicament . His sword was doing no damage towards her. So he through his sword on the ground and started punching her. It was not working as well, but he saw a sword on the wall which was crafted by magic by some mythical creature.
He grabs it and sliced right through Grendels mother. He grabbed her head as a trophy.