Minecraft wiki entry for Defense, associated text: 4#Make a hole on one side of your house that is 2 high and 1 wide. Leave the top block open, and for the bottom block, place a dispenser facing outwards, stacked with arrows. Place a pressure plate directly in front of the dispenser, so that you can stand at your window at night, draw a monster's attention, and lure it onto the pressure plate. This will activate the dispenser and effectively kill the offending mob. One will regularly find rotten flesh, bones and arrows underneath. The arrows can be used to replenish your dispenser. Make sure your pressure plate is made of stone, because otherwise, the drops of the dead mobs will keep activating the plate, causing the plate to be disabled for 5 minutes after every use, or until the player picks the items up.