The Diablo series has a boss called The Butcher who's been more prominent lately with his appearance in Diablo III. But let's not forget that WoW has its own. Doctor Theolen "The Butcher" Krastinov was a boss in the original version of Scholomance. Upon engaging him, he would let you know that "The doctor is in!" You had to kill him to summon the optional boss Kirtonos. Like many other bosses, he was removed from Scholomance during its revamp.
Or was he?
Now, Krastinov is actually a rare spawn that has a small chance to replace one of the trash packs following Rattlegore. He only spawns in the level 90 heroic version of Scholomance. Krastinov has the same abilities as his first incarnation: a bleed, a stun, and a self-Bloodlust effect.
He only has one item on his loot table, with a 100% chance to drop. Krastinov's Bag of Horrors is a transformation item that lets you sport the doctor's fashion, including his trademark bloody cleavers, for 10 minutes. It's a tribute to the quest item of the same name from classic WoW's Ghosts of Caer Darrow chain. We never knew exactly what was in that bag, and we never wanted to.
For you collectors out there, the bag has already been flagged as a toy in Warlords of Draenor.