The Crystal spider is a gigantic spider that lives in a giant web surrounding The Widow Of The Web. It attempts to kill (and devour) Ynyr during his attempt to reach The Widow and find out where the Black Fortress will rise. Ynyr uses The Widow's Sands Of Time to make him invulnerable to the beast, but upon escaping looks back and witnesses the Spider breaking into the Widow's home, to have its last meal.
The Spider is pure white and while appearing, and reffered too, as crystal, the spider is not actually crystal, merely albino, and almost completely see-through, with a large red organ in its abdomen thought to be the stomach. It feasts on humans, as any other spider would feast on insects.