Steve, he melts down aluminum, like old wheels and automatic transmission cases and pours them down ant nests (hills). Then very carefully digs out around it in a few days. Most people that do it use a water hose and shop vac when they get close, so they don't destroy the form. It's a form of art work. Some do ant hills and some do bees nests in the ground. Never seen one where somebody had enough molten aluminum to do a ground hog burrow....lol.