Centuries ago drow wizards attempted to breed a stronger and better armored spider for use as a war mount. The resulting creature was too slow to move with the armies, and disinclined to take any training whatsoever. The creatures were not unable to summon bursts of speed, and during a last attempt at domestication a number of the aberrations slew their trainers and escaped into the wild. The sloth spider resembles an oversized black widow with very long legs.
Slime Attractors. From a young age, sloth spiders attract green slime to them, which they have the ability to ingest. By adulthood, a sloth spider can draw enough green slime to it to cover a 15-foot diameter hole, and uses drained slime to cover its tunnels. Undrained slime follows in the wake of an adult sloth spider when they are within 100 feet.
Fond of Camouflage. The natural coloring of a sloth spider, along with its ability to regurgitate slime and cover itself with it without any ill effect, makes it difficult to perceive in its slime and fungus covered environment, such as the Fungi Forest.