Isopods are an order of marine invertebrates that belong to the greater crustacean group of animals that includes crabs and shrimps. Scientists think that there are around 10,000 species of isopods and half of them live in the ocean and the rest are found in coastal and shelf waters. Isopod refers to all legs being similar is size and shape.
But there is one subspecies that is exclusively terrestrial and that is a pill bug (sow bug or wood louse) found scurrying around in any backyard in moist dark conditions. Isopods are not bad or evil for humans. More likely they are just misunderstood.