He will start off underground. A few vines will come out of the ground. Destroy them, then a regular giant Juppie will drop off the vines on top of the stage. The giant Juppie monster will then appear and start to pound you with his head. Get near the giant Juppie that fell and wait for him to pound. Attack it, and he will get stuck. Go over to his neck and slash away. Repeat the process until he is defeated.