The Worm of the Dorstvlakte

The great caravan route across the Dorstvlakte lies abandoned. Whatever crosses it vanishes without a trace: carts, camels, people, dragged skin and all into the sand. The trade cities on either side are starving, and the guilds will pay gold for a solution.

Deep beneath the sand hunts the Grote Zandworm, older than the route itself, blind but tuned flawlessly to every tremor. It senses footsteps miles away and rises to swallow its prey in a single gulp. The desert nomads know the old way to kill it, but it takes nerve: you have to use yourself as bait.

You learn the tremor-tongue of the nomads, gather what is needed to lure and trap the worm, and scout its hunting ground without taking one step too many. You set a trap at an old mountain pass or a collapsed temple, somewhere the monster can be pinned, and draw it in with deliberate noise.

The twist: the Grote Zandworm is not alone, it has a nest, and the trap has to be timed perfectly for when the young one surfaces too. In the climax you stand atop the bait as the ground gives way, the maw yawns open tall as a tower, and at the last moment you must snap the trap shut, or vanish into the blind depths yourselves.