Cymothoa exigua is a unique parasitic isopod that lives in the mouths of fish. Though it may not have many commonly used synonyms, it is sometimes referred to as the tongue-eating louse or the tongue louse. This is because, after inserting itself into the mouth of a fish, it attaches to the tongue and essentially replaces it as the primary organ for consuming food. While this may seem gruesome, the cymothoa exigua does not actually harm the fish and is simply using it as a host. Despite its unusual habits, this creature has become well-known in the scientific community for its fascinating life cycle and behavior.