Spidersilk Rope (3.5e Equipment)
From D&D Wiki
Spidersilk rope, made only by sentient giant spiders, is sturdier and finer than any other type of rope. This rope has 6 hit points and can be burst with a DC 25 Strength check. It is incredibly supple and slightly adhesive, and thus provides a +2 circumstance bonus on Use Rope checks and on Climb checks to climb the rope.
An average spidersilk rope costs 50 gp, weighs 5 lb. and is 50 feet long.