you have a couple of ways to beat him. ledge take down, take down from behind, hit the magnet with the electric charge gun when he's close, get him close to a destructible wall and blow it up near him, use your disruptor on him. i believe you only need to catch him 5 times, but their are more ways to him those are the ones i used. if the games sees your not getting it Batman will link up with the bat computer and tell you the ways you can catch him off guard. Hope that helps.