Minecraft wiki entry for Snow_golems, associated text: A pushing turret's role is simple: Keep mobs away from your house. To do this effectively, they require a large number of snow golems, at least three, preferably more. It is possible to build one with a single snow golem, however, it won't be effective and will likely be killed if not in a protected turret. Four snow golems throw snowballs quickly enough to continuously push a zombie back.