Many adult millipedes can have more than 20 body segments, but a pill millipede is smaller and can roll itself into a ball to protect itself. Contrary to popular belief, there has never been a known species of millipede with 1,000 legs. Instead, adult millipedes can actually grow up to 200 legs. They have two pair of legs per body segment, unlike centipedes who have one pair of legs per segment.
Generally seen as just nuisances, millipedes typically pose no threat to humans. However, they can cause crop damage, which means any gardens or house plants are in danger of being attacked.