A mysterious creature, with a mixed quadripedal/bipedal gait, a rudimentary understanding of tools, and the playable character species of the game Rain World
It is strongly implied that slugcats are a product of bioengineering, descended from an artificial organism designed to clean the interior of pipes. Having since evolved away these origins, their adaptability and knack for getting in and out of tight spaces has both served them well, and not gone unnoticed.