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