Boss battle idea: Mobile heartstone

Imagine, if you will, a floating heartstone that appears in a level.

It floats around and comes after the dwarves, performing similar attacks as it does in the drilldozer mission- grabbing rocks from the terrain and smashing them down, calling crystals to grow and shoot lasers, and causing crystal structures to trap dwarves.

It has to be defeated in multiple stages, first by calling down a pod with special weapons which immobilizes it, and then by assembling a floating drill which acts like a larger version of the shredder drones to fly into the heartstone core.