Minecraft wiki entry for Defeating_a_village_raid, associated text: This is not really a trap, but it slows down mobs since they cannot push against the flow of the water unlike the player. Placing a water bucket at the raiding mob's feet slows them down, allowing you to take the raid mobs down using a bow from a safe distance. Pillagers will try to use melee attacks when in water, so you can kill the pillagers with ease.