Genus Oniscus, also known as the common woodlouse, is a group of isopods that can be found worldwide. Synonyms for this genus include the rough woodlouse, common pill-bug, and common roly-poly. These synonyms are commonly used in different regions and can refer to specific species within the genus. For example, the rough woodlouse specifically refers to Oniscus asellus while the common pill-bug and common roly-poly can refer to various species within the genus. Regardless of the synonym used, these creatures are often found in damp and dark environments, feeding on decaying plant matter. They play an important role in breaking down organic matter and enriching the soil.