Geist Ambusher

Geist Ambushers are geists found in the Pit of Saron. They spawn only after your party kills Forgemaster Garfrost. After which, on the path between Garfrost and the hill leading up to the cave, a group of freed slaves will annouce they plan on attacking the Scourgelord's location. These ambushers jump off a ledge and attack the group of freed slaves.

Upon implementation of the Pit of Saron instance, these mobs were humanoid. This was strange because all other geists in the game are undead. As of Patch 3.3.3, this has been fixed.