One other very cheap alternative.

Ingredients:

«» One of those pull string firecrackers
«» A plastic bag
«» Silicone glue/sealer
«» Oxygen & Acetylene

Put the string through the plastic bag, one end through the opening and the other end through the bottom of the bag. Seal the bottom string hole air tight with the silicone sealer/glue. Fill the bag with oxygen and acetylene. Tie one end of the firecracker to the thing you want to keep and the other end to a tree (or whatever) . When they go to drag the “thing” away it will sound like a shotgun going off right next to them. Guaranteed to leave skid marks in the pants.

This also good for Halloween hay rides with the primer of a ghost story about the crazy shotgun guy that haunts the woods. The tractor trips the string - BANG