Halaster Blackcloak: D&D Collector's Series Dungeon of the Mad Mage Miniature
Halaster Blackcloak: D&D Collector's Series Dungeon of the Mad Mage Miniature - Rules of Play says:
Halaster, the Mad Mage of Undermountain, is the deranged individual behind most of the traps and horrors found in the great dungeon under Waterdeep. Undermountain is his home, an amusement gallery in which others perform to entertain him. Halaster's true form that of a tall, gaunt, male human, but he uses magic to take on many other visages and shapes. No matter what form he wears, the Mad Mage giggles and mutters incessantly.