Jeering Spectre's Essence

Source
This item drops from:
 * Eldreth Phantasm in Dire Maul
 * Eldreth Spectre in Dire Maul
 * Eldreth Spirit in Dire Maul
 * Eldreth Apparition in Dire Maul

As a quest objective
This item is an objective of The Instigator's Enchantment.