The Destruction Device was a device used by Skeletor to keep intruders out of his secret factory on Stardica. It also served to make certain that Man-At-Arms would remain captive there.
Man-At-Arms was chained to a makeshift chair hidden behind the wall of the factory, in part of the mountain the factory was carved into. The Destruction Device was located on the ground right next to him. He-Man managed to locate his friend and mentor by using a scanner and got rid of the Destruction Device by picking it up and hurling it into the air, where it exploded high in the sky above Stardica. He then freed Man-At-Arms from his chains and dismantled what was left of Skeletor's factory build army.