Wall Creeps are single-eyed, spider-like monsters appearing in The Binding of Isaac: Rebirth. They first appear in Chapter 1 rarely, and also commonly in Chapter 2, 3, and 4.
They can be encountered occasionally on walls. They will try to line up with Isaac in a very quick speed, and spit 3 bullets in a horizontal line. They can move around on one wall but cannot move to another wall.
If the flight item (such as Fate, Lord Of The Pit, etc.) is obtained, Isaac can attack them safely by shooting diagonally. However, kill them quickly because they can follow towards him for contact damage. It also works on their related variants including Blind Creeps and Rage Creeps.