Dream vestige

A dream vestige is an intangible entity, more like a huge mass of fog with anguished faces appearing in it, stretching, twisting, and dissolving back into the vapor. It is accompanied by a chorus of faint voices, some moaning, some gibbering, and others laughing. The souls that make up the cloud are in constant torment, trapped in a nightmare, and they hate one another even more than they hate the world.

A dream vestige begins by gathering hundreds of nightmares, combining them, and infusing them with the energies of undeath. It grows by devouring any being possessed of a mind. It can pass back and forth between the physical realm and some sort of demiplane of dreams.

It burns with an insatiable hunger and snatches up living beings with tentacle protruding from its mass, dissolving them into nothingness. Only mindless undead beings such as zombies, skeletons, and golems can endure its touch.

A bard or someone able to weave emotions can defeat the entity by enflaming the dream vestige's wrath and self hatred until it would be strong enough to overcome any constraining forces and dissolve the fog-like entity. While suggested by the authors liberal flavouring, it is however not supported mechanically by the 3.5 DnD rules, and should not be assumed as factual beyond author liberty.