D&D 3.0: Tales from Mystara
The smallest of the four main cities, Losetrel is known for the bravery of its tailors. Spider silk, gathered from the webs of giant shroud spiders, is carefully cured to remove its paralyzing features, and is then woven into cloth and cut and sewn into white garments of considerable beauty.
The shroud spiders are not domesticated in any sense of the word. Their bite is poisonous, but is considered unprofitable to kill a spider, as they take years to grow a size at which they can spin usable silk. This means that the webbing must be stolen from the spider, usually accomplished by having one tailor lure the spider away from its lair by feigning to be trapped while another tailor grabs up the silk. This is a dangerous maneuver, since anyone within 30 feet of the spider can be hit by a paralyzing strand of web.
Webbing is also made into ropes that retain their property of paralysis for several months; these are often used as lassos by skinwing troops, or by ground forces traveling through tunnels near humanoid settlements.
The techniques first developed in Losetrel have since been adopted in other cities and settlements of the shadow elves.