Forge World was busy trying to give away a set of Titans. Chances are you didn't win one. It's ok. I know I didn't win one, either. But if you find yourself in the position that your 40k opponent did win one (or you just want a gigantic gun on tracks on your side of the board), you might want to order the new Mechanicum Ordinatus Sagittar.
That gigantic gun there is a Volcano Cannon taken to the extreme. I think part of the reason is that it leaves craters the size of a standard volcano in whatever it manages to get a solid hit on. Usually such a gun is found on Warlord Titans. But now you can slap some treads on it and go off-roading.