Horfs are disembodied human heads with their eyes gouged out. They are immobile, and receive high knockback from Isaac's tears.
Once the player enters the room, they will begin shaking but remain at the same spot. They will fire shots directly at the player when they're about 1/2 room width away from them, even though their shots can travel the entire room's length. This makes it possible to outrange the Horfs in almost all encounters with them; even if you're in range, they have slow rate of fire and their shots are slow-travelling as well, and can be dodged simply by moving slightly to the side.
- Besides having their eyes gouged out, Horfs also lack their upper teeth. This, when combined with the gargling sound made when they fire, suggests that their shots are formed by the blood from their mouth, instead of their eyes.