Magtheridon's Head

Magtheridon's Head is all that remains of the Pit Lord Magtheridon, who is finally defeated by a raid of adventurers into Outland. Once turned into Force Commander Danath Trollbane in Honor Hold or Nazgrel in Thrallmar, all of Hellfire Peninsula receives a two-hour area buff, boosting reputations with their respective bases.

Alliance receive the buff Trollbane's Command; Horde receive Nazgrel's Fervor.



Source
This item drops from Magtheridon in Magtheridon's Lair.

As a quest objective
Starts the quest:

The reward of both quests is the same, offering one of these four to select: