A Caravan beetle is a giant insect, 30 to 40 foot in length, and 10 to 15 foot wide, resembling nothing so much as a massive woodlouse or elongated, clawless crab. Its flattish upper carapace seems to be made from grey, lumpy rock, a covering harder than the hardest fired ceramics, and it moves along on six stumpy, crab-like legs. The head is small, spade-like and nestled deep within a fold of the rock-like dorsal shield. The visible sensory organs consists of five stalked, facetted eyes and a retractable snout, not unlike that of a butterfly.
The intelligence of the Beetle is exceedingly low, making it easy to control for anyone with psionic Talent, but its bulk and protective cover keeps it safe from most of the fast-moving predators of the desert. The Beetle can go for months without water, and seems to subsist mostly on roots and certain types of rock it digs up from the sands.
This lumbering, stony behemoth, resembling nothing so much as a flattened, mobile pile of rock, has been harnessed by the nomads of this inhospitable region, to serve as their mobile base of operations as they migrate from oasis to oasis as the seasons dictate.
The Aquurian Nomads, the wind-bitten, hardened children of the desert, raise their pennon-bedecked goat-skin pavilions and house-sized tents atop the relatively level backs of these beasts. The flattish "platform" on the back of the creature will, when the Beetle is up and moving, be some 10 feet above the ground, keeping its riders safely away from the ripping thorns, giant antlion traps and poisonous spiders, scorpions and snakes that infest the desert.
The predators of the desert avoid the lumbering Beetles, and, for the nomads, there is the additional benefit of not having to break and raise their tents every night. The various bands of Nomads travel in long caravans across the arid wastes, but can remain in relative comfort and safety atop their slow-moving mounts.
The Nomads breed the Caravan Beetles like other people breed horses, striving for an even gait, large back area, controlability and great endurance. Different tribes, depending on their routes of migration and specific standards, strive for different traits, and it is common to see a caravan followed by a small herd of half-grown Beetles.
This is sort of a "spin off" from the Locastus setting I´m working on, in that there are no Caravan Beetles in Locastus itself (although there are a few Aquurian Nomads). I just liked the idea so much I had to make a write-up out of it. There will be an entry in the Races of Locastus codex soon detailing the Nomads themselves. Hope you´ll enjoy it!