I run into this all the time, and I wonder if others do too. When you're in a fight with a small or med sized grendel, and smack em really hard- they'll come back to thier circle laying flat on thier backs half sunk into the floor. It doesn't seem to effect them badly- they still fight and all, and usually right themselves in a couple rounds. It's just extremely funny looking to see them floating half out of the floor on thier backs casting spells