The pill bug, also known as the roly-poly, is a small, terrestrial crustacean belonging to the order Isopoda. Unlike insects, pill bugs have a hard, segmented exoskeleton and seven pairs of legs. They are commonly found in moist environments, such as gardens and under rocks, where they feed on decaying plant material. Pill bugs are unique among crustaceans because they can roll into a ball as a defense mechanism, which is how they earned their nickname. They play an important role in the ecosystem by helping to decompose organic matter, contributing to soil health and nutrient cycling.