Void Shadow Dungeon
The Void Shadow Dungeon is a small area within which the Void Shadow spawned.
The room is floating in a Sea of Stars, suggesting that perhaps it is in Malas, or in the Ethereal Void (given that the monster there was called the Void Shadow, the latter would make the most sense).
The dungeon itself is shaped like an Ankh, with short and narrow "passageways" leading to the coffins shooting off from the central shape.
As of 6 October 2008 the Void Shadow Dungeon is still open, though nothing is there save for the coffins.