Roly-polys, also known as pill bugs or Armadillidiidae, are small crustaceans commonly found in moist environments like gardens and forests. They are unique among their relatives because they can roll into a ball as a defense mechanism. Roly-polys are detritivores, feeding on decaying plant material, and play an important role in the ecosystem by aiding in decomposition. Unlike insects, they have a hard shell and are more closely related to shrimp and crabs.