Answer:
I belive it's the arm of Grendel
Step-by-step explanation:
"Beowulf summons even greater strength and rips Grendel’s arm completely out of its socket. Fatally wounded, Grendel slinks back to his swampy home to die. Back in the mead-hall, Beowulf holds up his gory trophy in triumph. He proudly hangs the arm high on the wall of Heorot as proof of his victory."