Minecraft wiki entry for Trap_design, associated text: Falling uses a pit. When the target falls more than 3 blocks, they take damage on impact. The greater the distance, the more damage. Falling is generally combined with either a piston or a dispenser to push the target into the pit. These traps are easy to build, and mobs can be lured/pushed into them, but are large and can be difficult to gather drops. Chickens do not suffer fall damage. False floors are generally required if a player is the target.