Minecraft wiki entry for Shelters, associated text: Surprising foes makes any weapon effective! No one will ever know when a fancy statue is a literal bomb! To make one, fill a statue with TNT, then add some underground redstone leading to a button to activate it. Activating detectors makes this defense automatic,though beware of mobs or players setting it off! Building it near a base is not wise. Normal rails and one block of activator rail with some power applied can replace a large redstone usage if statue is lower than the shelter. Push a minecart with TNT down the rail to activate. Remember to add the Activator Rail early on the rail if possible for a quick countdown!