In-game pickup line
“Temporary demon form”
Mechanics
What The Nail does
- Each use grants half a Black Heart.
- For the room, Damage rises, Speed falls slightly, Isaac hurts enemies by contact and can break rocks by walking into them.
From the game files
Recharge
Standard recharge6 room clears
Standard room-clear recharge. Batteries and other effects can change how quickly it refills.
Achievement #9
How to unlock it
Complete Boss Rush as Azazel.
Unlocking an item and finding it during a run are separate steps.
Explore more unlocksIn a run
Practical note
Use it for dangerous rooms or to reach a pickup behind rocks, while accounting for the slower movement.
Reference
Game data and sources
The item ID, quality and pool listings, icon, game-file tags, and short pickup line come from the extracted Repentance files. This effect explanation is an editorial summary checked against the references below. Repentance+ can differ. Charge and pickup values shown above also come from the extracted items.xml.
