Minecraft wiki entry for TNT_cannons, associated text: Sand cannons are a variation of the TNT cannon that is harmless. The concept is the same, but uses sand as a projectile. Also, the sand must be falling as the TNT in the cannon explodes, shooting the sand, otherwise, nothing happens. It is possible to pile the sand up to make a "sand shotgun cannon", which can fire multiple sand blocks at different distances. Note that the sand cannon generally only fires in one direction and is not destructive. It can be used for pelting sand at people's plots in creative multiplayer plots servers, and in turn, making moderators mad. Sand cannons are also commonly used by griefers on multiplayer servers. While the victim is doing renovations on their claimed land, griefers may build a sand cannon as quick as possible as to not being caught, and fire several blocks of sand to the top of the victim's house while they are doing construction in hopes that they will break a block on their roof and have sand fall on top of them.