This creature is part of the Mucosa family. A mucosa has a humanoid head and chest and spider legs and abdomen. It is equipped with mandibles and sharp, spear-like arms.
Documents recovered by adventurers in all campaign theaters: Ehb, the Utraean Peninsula, and even the Isle of Utrae, uniformly blame the existence of these monsters on insane magical experiments with spiders.
Dark mucosae are red-colored. They may be found leading packs of plain and Vile mucosae. Specifically, dark mucosae will appear toward the end of Wesrin Cross, before the giant spider boss, as well as in Hovart's Folly on the Peninsula.
Dark mucosae will engage their enemies in close combat, attacking with their spearlike arms and their mouth. They are much stronger in melee combat than ordinary mucosae, and aside from the unique giant spider, are the toughest type of foe encountered in Wesrin Cross.