Dr. Zalost's Tower is the lair of Dr. Zalost. It's also a vehicle.
It is mobile tower on tank treads with mechanical spider legs. Dr. Zalost's room is at the top of it. There are sprial stairs inside it. The middle room is where the uhappy cannonballs are made from a giant cauldron, it's also where rat shoots them out the the middle window. The only entrance is a secret elevator hatch at the bottom.