Rat
This NPC can be found in Stranglethorn Vale (2), Arathi Highlands (28), Alterac Mountains (4), Silverpine Forest (8), Hillsbrad Foothills (5), Stonetalon Mountains (9), The Barrens (4), Desolace (25), Scholomance (55), Zul'Gurub (11), The Dead mine (11), Stormwind City (26), Scarlet Monastery (10), Tirisfal Glades (77), Western Plaguelands (10), Undercity (2), Naxxramas (26), Dire Maul (38) and Sunken Temple (1).