Hi, I want to share with you my finding and my attempts to bring it to life.

First of all, maybe some of you knew about this interview with Kenneth Scott, art director of Doom 3: http://pixologic.com/interview/artist/archive/kenneth-scott

In there you can see a bit of his great work, and among them, this beast:
In Doom Wikia this thing appears as an unfinished model cut from the game. Searching through the vast game files (as I usually do in my lonely nights) I stumbled with a complete set of textures for an apparently non existing model file, and long story short, I managed to find the corresponding mesh.

To my surprise, it was that monster from the image, and I couldn't help myself, I needed to rig the hell out of that mesh and see it in motion:
Currently I'm animating all what is needed and trying to put it in the game to make it an actual enemy. So far I'm learning upon the process but things are going well so far I guess:
As you can see, the guy is quite bulky, and is a bit taller than a Hellknight. I think this could be some kind of brute lumbering demon, basic in behaviour (right now it has the AI of a zombie) and with a lot of health.

Anyways, I'm happy to take this thing into the light, I think Kenneth Scott is a very good artist and did a very good job with Doom 3, is a pity that this piece of work was buried in the game files like this for so many years and never used.