On the Astral Sea
These terrifying flatworms are native to the deserts of Athas. The genies of the Elemental Chaos have long ago extracted these monsters to breed—the material silk wyrms use to cocoon their victims and line their nests is as fine as silk, but durable as spider silk and resistant to the elements. Because of the silk wyrm’s predatory habits and dull intellect, it takes a strong or rich trainer to keep silk wyrms in captivity long enough to be profitable. Instead, most market-quality silk wyrm fabric is harvested from their nests by expendable labor or would-be adventurers.