A Bone-spider, as they appear in the RPG
The Bone-spiders are creatures that live in The Blind Man's Catacombs. They are said to weave the silk that makes up the pages of the Blind Man's books.
Scribe Sigma of The Archive said that she witnessed the spiders and that the description "spider" does not really do them justice.
In OH GOD THE RAPTURE IS BURNING, they can be found in the Valley of Song, and spin the only artifacts of color in the domain.