Minecraft wiki entry for Defense, associated text: • A self-destruct system might be useful, to prevent others in multiplayer from stealing your belongings. For this to work, the TNT has to be concealed in a wall, and there should be redstone (that is concealed) attached to a button to activate the TNT. It is also recommended that you have a blast-proof room where you store or hide in before you activate the self-destruct. The button should also be in this room.