Spiky Massage Ball Excellent for Working on Troublesome Muscles. Beastie Series products expand the RumbleRoller experience to provide more intense, versatile, portable, and affordable massage options. The RumbleRoller Original Beastie is an aggressive massage ball that is the heart of this series. Beasties Series products don't replace the RumbleRoller, but they are more specific in purpose. Use them to dig deeper into a troublesome area, or to work with greater detail on smaller muscles – e.g. those of the forearms and calves.