Grendel and Beowulf
Grendel appears in the guise of a fearsome dragon, who lives in a lair inside a cave. He has powerful claws and has the strength of thirty men, the only one able to defeat him is Beowulf, man of extraordinary strength and indomitable courage, called by the king Hrothgar to be instructed to kill the monster who for too long persecuted peasants and made the slaughter of innocents.
Only after being surprised in his bed in the middle of the night, the hero of the story can hurt to death the dragon, ripping out an arm and sentenced him to bleed to death. Immediately after Beowulf has made this gesture, Grendel makes a inhuman scream and run away to avoid being definitely killed by that powerful man.