Minecraft wiki entry for Piston, associated text: The piston head is a technical block used as the second block of an extended piston. A block state defines whether it is a normal or a sticky piston head. It can be placed using the /setblock command or with the debug stick, though if not part of a proper piston, it disappears after receiving any block tick, such as when a block is placed next to it unless the player uses the debug stick. It drops nothing.