Hello Matt, to kill the Dragorth, you must lead him through trees multiple times to finish him off. I recommend going slow enough for him to stay on the screen, but fast enough to not get him. Also, to my knowledge, you cannot kill the mimic chests, but you can tell them apart from real chests. For example, the mimic chests have "feet" and are targetable when holding a sword. Real chests look different and cannot be targeted with a sword. It may be possible to kill the mimic chests after obtaining the ice pencil.