The gulyabani is the hairy, oversized and frightening thing met in empty places — the desert, a graveyard, a road at night. The name joins the Arabic ghūl with the Persian biyābānī, "of the desert".
Its real work in the telling is to confuse the traveller: it makes noises, calls out in a familiar voice, takes the road away. It leads astray more often than it kills. Which is why the advice against it is always the same — don't look back, don't answer it.
In Balbal, The Ghoul Desert is the sixth floor of the Underworld: a sea of sand under moonlight and silhouettes that appear and vanish on the horizon.