The Nail

Effects

On use:
- (Removed in Repentance) Gives one (Soul Heart) Soul Heart, +0.7 damage, -0.18 speed, and the ability to destroy most obstacles by walking into them. Cannot be stacked in one room.
  - (Added in Repentance) Gives half a (Black Heart) Black Heart, +2 damage, -0.18 speed and the ability to destroy obstacles for the current room.
    - If used multiple times in one room, the speed penalty only applies once, but the damage buff can stack. Each subsequent damage buff becomes less effective for each use
- Allows Isaac to deal 40 contact damage to enemies for the current room. Does not prevent Isaac from taking contact damage. It can be applied only once per second per enemy.
- (Added in Repentance) Isaac's tears become red for the current room.
(Added in Afterbirth) This item belongs to the Leviathan set. Collecting three items from this set will transform Isaac into Leviathan.

Isaac makes a demon sound when taking damage while this item is in use. This is quieter than Isaac's standard damage sound and is easy to miss.
(Added in Repentance) The damage increase from The Nail can be stacked in the same room, but the speed penalty does not increase.

(Added in Repentance) Book of Virtues: Spawns black wisps on the inner ring. Wisps shoot nails that deal double damage from standard wisps, and have increased knockback, akin to (Blister) Blister.