Remus must have picked it up and narrowly dodged another swipe from Fenrir. In that moment, was when Remus regained his composure and grabbed Fenrir by his outstretched arm. The next moment was one I have seen myself done, but with a sword. It was not a pretty sight as blood spurted from Fenrir’s shoulder as Remus’ other clawed hand cut deep into the joint, ripping the arm off. 