This item is no longer available in game.
You must obtain a Chimera of Fear from the Sha of Fear in the Terrace of Endless Spring for the quest http://www.wowdb.com/quests/31481-fear-itself.
This item drops in all three raid difficulties (LFR, Normal, Heroic). It will also drop regardless of whether or not you've already killed the Sha of Fear that week. (Source)