Answer:
Arms
Step-by-step explanation:
In the tale of Beowulf (told by Angelo-Saxons), Grendel's skin is made impenetrable by the swords Beowulf and his men carry, so Beowulf rips the arms of Grendel mortally wounding the creature. Grendel's bleeds to death in his marsh den from his wounds, later after Beowulf kills Grendel's mother; Beowulf finds Grendel's corpse and severs its head taking it home as a trophy.