A Link to the Past
Wall turrets first appear within the Desert Palace in the room that has the Big Key. They are connected to the wall and move as if they were on a rail. They will shoot Balls out towards Link. Wall turrets are always on opposite walls making the balls roll across the room in a crossfire. The wall turrets themselves cannot be defeated and neither can the balls that are shot out. Link can only avoid them. The wall turrets will shoot out balls in consistent intervals.
The wall turret later appears in the Palace of the Four Sword. These wall turrets appear with the Spiked Roller while moving above water, being the only wall turrets to do so. In order for Link to avoid the balls coming from the wall turrets, he should dive underwater and swim away.
Strangely, the amount of balls that are shot out of a wall turret depends on the amount of enemies located in the adjacent rooms. If the adjacent rooms are filled with enemies, the maximum amount the wall turrets will shoot is four balls. The wall turrets will still go through the animation as if they are shooting balls, but nothing will come out.