The feared avar shlin is an intrusive pest originating from radioactive swamps and dark forests. This long wriggler is best known for the debilitating toxin it induces within the eyes of anyone that sees it. Something about the avar shlin's image projected on a human retina causes a chemical reaction that produces what has been known as avar sludge; this goo slowly dissolves the intricate structures within the eyeball, resulting in a rare form of incurable blindness where the victim can still see, yet can't understand what is being seen. Avar shlin have been known to decimate entire kingdoms from within.

Despite their destructive potential, avar shlins are not aggressive by nature and prefer to avoid confrontations with larger creatures. They are nocturnal, and during the day they will burrow into the ground to avoid detection. Their diet consists mainly of small insects and rodents, but they have been known to scavenge for larger prey if necessary.