This boss may be hard for beginners but is actually pretty simple. Just rush towards it and run into it without dashing. You'll grab it and begin rotating. The basic goal is to launch the boss through the various walls until you reach the end of the course. Press A/B when you are facing the direction you want to launch it and be sure to aim so you go through the breakable portion of each obstacle. You'll know it's breakable if you can see cracks and broken areas in the structure. It may take a try or two to learn to aim the boss, but once you do this battle is a cakewalk. Just be careful where you aim, because if you hit the wall you'll bounce the boss backwards quite a distance.