Corrupted Brain Stem

Corrupted Brain Stems dropped from:
 * Blackfathom Oracle in Ashenvale
 * Blackfathom Sea Witch in Blackfathom Deeps
 * Fallenroot Shadowstalker in Blackfathom Deeps
 * Fallenroot Hellcaller in Blackfathom Deeps
 * Blackfathom Tide Priestess in Ashenvale
 * Lady Sarevess in Blackfathom Deeps
 * Fallenroot Satyr in Ashenvale
 * Fallenroot Rogue in Ashenvale
 * Blackfathom Myrmidon in Blackfathom Deeps

As a quest objective

 * Researching the Corruption
 * Researching the Corruption (Classic)