When Isaac is hit, 1 point of an item's charge is filled.
Maw of the Void
+1.0 Damage Up. After continuously firing tears for 2.5 seconds, a red cross appears on Isaac's head that, upon releasing the fire button, creates a black ring that rapidly deals damage equal to Isaac's tear damage to any enemies in contact with it.
Spawns an orbiting razor that damages enemies it touches and inflicts bleeding on enemies, causing them to slowly take damage over time.
Spawns an egg familiar, which cracks and turns into a random charmed enemy when Isaac is hurt. The egg regenerates upon entering a different room.
Tears are now fired in an arc. Upon hitting the floor, an obstacle, or an enemy, they burst into many smaller tears in all directions. Increases tear delay.
Grants Isaac one full red heart container.
Key Piece 2
Combined with Key Piece 1, unlocks the golden gate in the starting room of The Chest and Dark Room to fight Mega Satan.
-2 Tear Delay. Tears float in position until firing ceases, after which they will fly off in the direction they were shot in.
Wanders about the room, occasionally spawning blue spiders.
Randomly while firing tears, Isaac will stop firing and turn red, where he will charge and release a lot of 'tears' in one go. In the burst of tears is a kidney stone which deals a lot of damage.
+5 bombs. Bombs stick to enemies and spawn 2-4 blue spiders if they kill an enemy.
Reduces all Shop prices by 50%, rounded down to 7 coins for an item, rounded up to 2-3 coins for a pickup.
Increases speed and reduces character size. Also gives a random pill.
Increases damage and speed. Upon entering a room adjacent to a secret room, a howl sound effect will play.
A demonic familiar that follows Isaac and shoots tears identical to Isaac's in terms of damage, range, fire rate, and effects.