Giant trolls are on the loose. But don’t worry—they’re friendly! Artist Thomas Dambo uses recycled wood from fallen trees, old fences, and trash heaps to create his sculptures.

So far, Dambo and his team have built more than 80 huge trash trolls in Denmark, China, the U.S., and other countries. Each takes about 800 hours to build and some are 30 feet tall. Dambo says his goal is to give trash new life by recycling it in fun ways.