Boredom struck, so went farsighting.
Came across a rather intresting looking fellow, he's listed as a ?? Boss and has 261M HP like the Sha of Anger.
Anyways, here's a screenshot. Didn't really get any other good screenshots before Farsight ran out, gonna go see if I can find him again though!
Found another screenshot I took, from a distance this time;
One where you can see the mobs on its back a bit better (see bottom of post for fullscreen img);
Front view;
Fullscreen images:
http://i.imgur.com/LCV8V.jpg
http://i.imgur.com/F2eye.jpg
http://i.imgur.com/bX2CO.jpg
http://i.imgur.com/SU37N.jpg
http://i.imgur.com/Az2E4.jpg