Grendel's mother had harmed Beowulf. "Then he saw a blade that boded well... An ancient heirloom from the days of the giants, an ideal weapon" (Heaney 1557-1559).
"A light appeared and the place brightened the way the sky does when heaven's candle is shinning clearly... Now the weapon was to prove its worth" (Heaney 1570-1577). Beowulf had avenged the horrific acts Grendel and his mother had committed. "Beowulf in his fury now settled that score: he saw the monster in his resting place, a war-weary and wrecked, a lifeless corpse, a casualty of the battle in Heorot" (1585-1588).
OMG.. There's Grendel's corpse, let me take his head to the king
I wanted to bring back the sword, but it melted. "It was a wonderful thing, the way it all melted as ice melts" (Heaney 1607-1610).
Huzzah! We wished you would return alive. You have proved to be the best!