That was built before the gw kit came out. Scratch built with Vermin Hulk, Steam Tank and a few other bits. Named Lefty.
Oh man, that is AWESOME!!! Is that a conversion? I don't recognize it as a retail GW kit or a kit you could buy anywhere else. Looks like the flesh parts might be some bits from GW's Hellpit Abomination? That is disturbing, gruesome and fantastic all at the same time. Great work!!