Rat
This NPC can be found in Stranglethorn Vale (3), Stormwind City (45), Arathi Highlands (38), Silverpine Forest (36), Hillsbrad Foothills (5), Alterac Mountains (12), Tirisfal Glades (152), Desolace (56), Stonetalon Mountains (15), Zul'Gurub (20), Scarlet Monastery (13), Sunken Temple (1), Uldaman (1), Deadmines (3), Dire Maul (11), Naxxramas (3), Terokkar Forest (91), Shattrath City (26), Bloodmyst Isle (26), Azuremyst Isle (5), Ghostlands (24), Nagrand (63), Drak'Tharon Keep (2), Karazhan (10), Scholomance (10), Auchindoun: Mana-Tombs (4), Howling Fjord (77) and Dalaran (2).