Black Rat
This NPC can be found in Duskwood (21), Western Plaguelands (20), Icecrown Citadel (19), Utgarde Keep (15), The Forge of Souls (9), Utgarde Pinnacle (7), Halls of Stone (7), Ahn'kahet: The Old Kingdom (5), Pit of Saron (5), Drak'Tharon Keep (4), Wetlands (2), The Slave Pens, Shadowfang Keep, The Shattered Halls, UNKNOWN, Molten Core, Sunwell Plateau, Razorfen Downs.