Kidney Stone is an unlockable passive item in The Binding of Isaac, added in the Afterbirth DLC.

Firing tears will occasionally cause Isaac's head to turn read and charge an attack. Releasing the attack will fire a kidney stone that deals 5x Isaac's damage and pierces enemies, followed by a rapid, inaccurate spray of tears.

When the effect is activated, Isaac gains a temporary x6 fire rate multiplier that decreases rapidly.

The effect occurs immediately when the item is acquired, and every ~25 seconds.

Isaac cannot fire tears normally until the kidney stone effect ends.

This page shows the latest information as of the new Repentance+ (Online Co-op) DLC.
To see information about this item for the previous Repentance version, check this page instead.

Complete challenge #29: Onan's Streak.

Kidney Stone can be found in the following item pools:

The following tags are applied to this item:

Below is the Internal Item Description as shown in-game.
Note that some stat changes are not displayed here. Please see the main description for the full effects.

Kidney Stone

• Occasionally tears will slow and stop, making Isaac flash red and charge an attack
• Releasing this charge unleashes a barrage of tears and a kidney stone that deals 10x Isaac's damage
• Abyss: x1 locust 1x Isaac's damage

• Check out the item description on the external Isaac Wiki.