Tharros the Wanderer was able to create these in the Feywild to fight The Mighty Menagerie.
Not much else is know about them. They seemed able to replicate many of the powers and abilities of the person they mimic.
I really do try to make most of this original, but since Forgotten Realms is an integral part of the world I can't help if anything is used without formal permission, but is still "fair use" as I am just using this for my private games.