The Convergence colossal. It's a big hovering robot that spawns small hovering robots and fires spikes and harpoons that drag enemy Warjacks close enough to be demolished by its giant drill-vices. In other words, awesome.
I tried using metal spray to speed up painting it, but that didn't work very well, as I used too much of it and it covered some of the small detail in places. Still, it looks decent enough on the tabletop.