From Oddworld Library

Slurgs are simple invertebrates considered the lowliest life forms on Oddworld. They that scour forest and cave floors for food, typically Fleech excrement and offal. Travellers are warned to watch their step as Slurgs' gaseous bodies emit a high‐pitched squeak when squashed, waking up any nearby Fleeches. It is joked that Slurgs actually steer themselves underfoot.