Black Rat
This NPC can be found in Razorfen Downs (28), Duskwood (22), Western Plaguelands (20), Kezan (17), Hellfire Citadel: The Shattered Halls (16), Icecrown Citadel (25), The Forge of Souls (9), Pit of Saron (8), Utgarde Keep (18), Halls of Stone (7), Ahn'kahet: The Old Kingdom (5), Coilfang: The Slave Pens (4), Shadowfang Keep (12), The Sunwell (4), Violet Hold (3), Drak'Tharon Keep (4), Utgarde Pinnacle (7), Wetlands (2) and Scholomance (1).