Their behavior is mixed between a regular Fatty and Stone Grimace. Like regular Fatties, they directly follow the character but never use the farting ability. They are completely invincible and can be only killed if all other enemies are defeated before completing the room, similar to Death's Head.
- Stoney is a first Afterbirth † enemy to be revealed while the DLC's under development.
- They were originally named "Walking Stony".