Not a GW miniature (ha, ha I have broke the spell), I think it's supposed to be an ultra large (the scale on the pack said 1/144 which I thought was amusing) BattleField robot thingy.
I got it as it (was in a 'sale' and) suited me as a bit of mobile heavy weapon support for my 25/28mm Space Marines/Men and the like. A little friend perhaps to Hammerstein.
I think his name was "Grizzly Bear". It was also an experimentation with the Anita Acrylic Metallic Paint range. I think I need more shading, grime and dramatic highlighting.