Rat
This NPC can be found in Tirisfal Glades (89), Howling Fjord (77), Naxxramas (100), Terokkar Forest (46), Desolace (32), Stormwind City (26), Ghostlands (25), Nagrand (24), The Culling of Stratholme (21), Bloodmyst Isle (18), Arathi Highlands (16), Scholomance (55), Zul'Gurub (11), Deadmines (11), Scarlet Monastery (10), Shattrath City (8), Alterac Mountains (7), Karazhan (42), Silverpine Forest (6), Stonetalon Mountains (6), Auchindoun: Mana-Tombs (4), Hillsbrad Foothills (4), Azuremyst Isle (2), Dalaran (2), Drak'Tharon Keep (2), Stranglethorn Vale (2) and Violet Hold (1).