The one in the cave with webs and the transformation
Oh that. Yeah, non-drow lady courts the favor of Lolth and transforms herself into a Phase Spider Matriarch. She appears to have been favored by Lolth. If you read all the books there are inspiration points to be had. I don't think there was much more to it, there are allusions that she was trying to show up the drow priestesses who rejected her.
