Kidney Stone

### Collection Grid

*(page 4, column 15, row 4)**(page 4, column 15, row 4)**(page 4, column 16, row 4)*

### Unlock Method

  Complete The Guardian (challenge #30)
 Complete Onan's Streak (challenge #29)

**Kidney Stone** is an unlockable passive item added in *The Binding of Isaac: Afterbirth*.

## Effects

* -0.2 speed and maximum speed.
* -15 range.
	+ -17 range.
* +2.0 tear falling speed.
	+ The increased tear falling speed and decreased range results in slightly increased firing distance.
	+ The increased tear falling speed and decreased range results in nearly identical firing distance.
* Occasionally, firing tears will cause Isaac to charge an attack with his head pulsating with a red color. After the attack has charged up, the fire button can be released to fire a kidney stone that does 5 times Isaac's damage and pierces enemies, followed by a rapid, inaccurate spray of tears.
	+ This effect occurs approximately every 25 seconds.
	+ Isaac won't be able to fire tears normally until the kidney stone has been fired.
	+ The kidney stone has approximately twice the range of normal tears.
	+ The barrage will continue for its full length between rooms, as will the state of charging the attack instead of firing tears.

## Notes

* Tints tears red. This is only a cosmetic change.
* will still fire tears normally while retaining the barrage effect, making this a good item for  Lilith.
	+ The barrage from the Incubus will be in a straight line (similar to ) instead of an inaccurate burst.
	+ The kidney stone itself will come out of Lilith, not the Incubus follower, even though she cannot fire tears. The barrage of tears will still only come from the Incubus. This also applies if blindfolded as another character.
	+ This is the only item to be able to override the Grayscale easter egg.
	+ This item does not appear to work at all for   Tainted Lilith.

## Strategy

* Activating this item before entering a difficult room, like a boss room, can allow you to deal a lot of damage right away. To do this, simply hold the attack button until you stop shooting tears.

## Synergies

* : Whenever the kidney stone is fired, the tear barrage will continuously charge and activate Maw of the Void until Isaac can fire normally.
* /: Whenever the kidney stone is fired, the tear barrage will continuously charge and activate these items' effects until Isaac can fire normally.
* : The temporary tears up from the kidney stone burst becomes a permanent x6 fire rate multiplier.

## Interactions

* //: Only fires one stone.
* : The stone will not hover and will travel regardless.
* Azazel/: Overrides Kidney Stone. Speed and range downs still apply.
* : When Kidney Stone activates, it fires one kidney stone and then no more tears until tears stat is under a certain value (unknown).
* : Charging the barrage pauses the Cursed Eye charge bar - if the bar is not full and Isaac is hurt, he will teleport. Firing during the barrage will neither fire tears, nor show the charge bar, but will still charge Cursed Eye. Being hit while the invisible charge bar is not full will teleport Isaac.
* : Overrides Kidney Stone. The range down ( or tear height down) is especially harmful with Dr. Fetus, making self-damage very likely.
* : Overrides Kidney Stone.
* //: The stone cannot split into smaller stones.
* The Forgotten: The Forgotten will swing his club rapidly instead of shooting the burst of tears (The Forgotten still fires the stone normally).
* : Overridden by Haemolacria. Only stat changes apply.
	+ Fires a barrage of Haemolacria tears upon activation
* : The stone will only spawn sparks when hitting enemies.
* : Stats are greatly increased during the barrage. The harsh speed and range down make Libra a large stats down.
* : Overrides Kidney Stone.
* : The stone will not grow bigger as it travels, but it will increase in damage.
* : Occasionally, Isaac will stop automatically firing, and an attack key must be held to release the kidney stone and continue firing.
* : Overrides Kidney Stone.
* : Overrides Kidney Stone.
	+ When also having , does not override, however the combination of the two items is not properly implemented and sometimes Kidney Stone will prevent Isaac from shooting.
* : Number One's range down overrides Kidney Stone, for an additional -0.62. The stone is not affected by the range decrease.
* : Overrides Kidney Stone.
* : Overrides Kidney Stone.
	+ Fires the stone like normal, followed by a barrage of Technology lasers.
* : Overrides Kidney Stone.
	+ : Synergizes now, behaving pretty buggy however (look into "bugs" down below).
* : Firing the urn counts as fire time but the urn must be put away for Isaac to charge and shoot the kidney shot. Switching to the urn while auto-firing from Kidney Stone forces the urn to fire as well.

## Trivia

* "Matt" refers to Matt Kap, a pixel artist for *The Binding of Isaac: Rebirth*, who has once been afflicted with a kidney stone.
	+ A kidney stone is a hard deposit made of minerals and salts that form inside kidneys. It will usually pass through the urethra, which is often a very painful process.
* When Isaac enters a room with half a heart and holding this item, he will leave a small puddle of blood rather than pee.