This is Zoosphaerium villosum, from the diplopod order Sphaerotheriida, sometimes known as giant pill millipedes. These millipedes can roll into a ball when disturbed. In this coiled position, most sphaerotheriids reach the size of a cherry, a golf ball, or are as small as a pea. But this species from Madagascar can roll into a sphere the size of a baseball! When rolled-up, predators are unable to uncoil giant pill millipedes, since their armored plates lock together creating a sealed ball. A few giant pill millipede species are able to produce sound through stridulation during courtship, the only millipede taxa known to do this.