Corrupted treant

Corrupted treants are wretched tree-creatures who were once proud, immortal defenders of Ashenvale forest. Yet, when the Burning Legion invaded the world in ages past, its demonic energies corrupted many of the ancient tree-men and drove them into shadow. Now these tortured creatures live only to spread their corruption and hatred of all living things.

In World of Warcraft
They appear as Withered Ancients in northern Ashenvale.