Murloc Puddle Lord

The Murloc Puddle Lord is a unique mob found in the Warcraft III: The Frozen Throne Undead campaign in The Dark Lady scenario. It is possible to take control of him. Sylvanas and her banshees took control of the murlocs nearby of the battle including him.

Speculation
As he does not appear in World of Warcraft, the Murloc Puddle Lord may have been killed by the Dreadlord Insurgents at some point during the war. Alternatively he could serving as the Dark Lady's eyes and ears in the sea.

Statistics of Murloc Puddle Lord from Warcraft III

 * 700 HP
 * 500 MP
 * 15-21 normal melee damage
 * 0 heavy armor
 * Abilities
 * Ensnare (makes flying units attackable by melee units and incapacitates)
 * Blizzard (ranged AoE damage)
 * Death Coil (ranged direct damage to living or direct heal to undead unit)