Rat
This NPC can be found in Tirisfal Glades (81), Howling Fjord (71), Naxxramas (100), Scholomance (55), Terokkar Forest (52), Karazhan (41), Dire Maul (38), Desolace (32), Arathi Highlands (31), Stormwind City (26), Ghostlands (25), Bloodmyst Isle (18), Arathi Basin (17), Nagrand (17), The Deadmines (11), Zul'Gurub (11), Scarlet Monastery (10), Shattrath City (9), Alterac Mountains (7), Western Plaguelands (6), Grizzly Hills (6), Stonetalon Mountains (6), Silverpine Forest (5), Hillsbrad Foothills (5), Mana-Tombs (4), Azuremyst Isle (3), Stranglethorn Vale (2), Drak'Tharon Keep (2), Dalaran (2), Undercity (2) and Violet Hold (1).