Dark Wisp
A Dark Wisp is an evil creature that physically resembles a Wisp but larger and, well, darker.
They have been seen in-game a few times, most notably when attacking the Lycaeum in Moonglow. During this event, Dark Wisps dropped special treasure chests as loot. They also accompanied Fetid Essences and Fallen Warriors during the Blackrock Detector event of March/April 2008.