Orb wraith

Orb wraiths were incorporeal undead formed when half a dozen or more wraiths merged together at a location of powerful negative energy.

Description
Appearing somewhat like an enormous mass of darkness comprised of various humanoid features, an orb wraith was a constantly shifting amalgam of insubstantial limbs, faces, and shining red eyes. Numerous bolts of purple-black negative energy would crackle and spark throughout an orb wraith's body, not unlike a thundercloud.

Abilities
Although an orb wraith lacked the physical presence to exert force upon its surroundings, the creature was notably swift and able to react quickly to multiple enemies, despite its size.

Perhaps its fundamental ability was an orb wraith's power to assimilate lesser wraiths. If the orb wraith slew a wraith, then it would add that creature to its mass, growing larger and stronger in the process. Eventually, an orb wraith could grow so large through this means that it would divide into two smaller orb wraiths again.

The orb wraith's touch was a great bane to living creatures as the barest touch could drain the health of even the hardiest individual. Much like other wraiths, any living creature that was slain by an orb wraith would rise shortly after as a normal wraith. These newly created wraiths were under the control of the orb wraith until it was destroyed.

Much like the enervation spell, an orb wraith could emit a thin purple-black life-sapping ray at any creature within 60 ft (18.2 m).

These creatures were incorporeal and could only be harmed by spells, spell-like or supernatural abilities, enchanted weapons, other incorporeal creatures, or weapons with the ghost touch quality.

Any domesticated or wild animals within 90 ft (27.4 m) could sense an orb wraith and would not willingly approach the creature.

Psychology
As essentially a conglomeration of ordinary wraiths, an orb wraith shared much of their twisted mentality. However, an orb wraith seemed to also manifest a much higher intellect than its lesser kin.

History
Orb wraiths rarely appeared outside of the Negative Energy Plane, but on the few occasions they did it was only within concentrated areas of negative energy, hence earning their "orb" moniker. Noted focal points included:
 * The orb at the center of the Undying Temple in Maerimydra, during the Silence of Lolth in 1372 DR
 * The mythallar chamber within the Crypt of Augathra the Mad, in 1374 DR.

Appearances

 * Anauroch: The Empire of Shade
 * City of the Spider Queen