Sharpclaw, Pack Leader, is a Unique Winged Talus found in the Battlefields of Eternity in Act V of Diablo III. It spawns for A Diversion event, and killing it is required to complete it.
In combat, it has Frozen Pulse, Desecrator and Thunderstorm affixes. However, its real weapon are hordes of Winged Talus swarming around, which will spawn again and again until their leader is dead.
Sharpclaw itself is easily recognized by its greatly increased size.