In a response of two to three sentences, explain how the action described in the following lines show grendel as a monster. "but on earliest occasion he quickly laid hold of a soldier asleep, suddenly tore him, bit his bone–prison, the blood drank in currents, swallowed in mouthfuls: he soon had the dead man's feet and hands, too, eaten entirely."

You would be looking for context clues in your quote that describe, "Grendal", as being a monster.

"...the blood drank in currents,"
"...he soon had the dead man's Feet and hands, too, eaten entirely"

Both those quotes seem to be monster-ish to me.
I don't know if this Grendal is a literal or symbolic monster, ie: cannibal.

I'm not going to directly tell you what to write but it should just be as simple as saying how each quote (I recommend using two quotes) about what Grendal is doing is also something that a monster might do.