It's described just the one time in the Dream-Quest of Unknown Kadath, but the concept of the forefather of all Shantaks charmed me. Here it is about to eat two tiny humans while a normal Shantak flutters next to it.
I originally planned on making it a steely gray color, but I decided to make it reddish, to indicate the fading that comes with age. Its mane has gone from black to white as well.