Umbral blot

This article contains information from the Warcraft RPG which is considered non-canon.

Umbral blots are creatures found in the Twisting Nether and are described as mobile spheres of pure void. Mutated umbral blots travel through the Twisting Nether, growing larger every time they consume a physical object. If they grow too large they could threaten all of creation. But this is unlikely an issue as heroes have been known to destroy them.