Glass Cannon 
Effects
- Fires a single high-damage piercing tear which can travel over obstacles.
- The damage dealt by this tear is ten times Isaac's damage, plus a flat 10 damage.
- The shot has an additional 1.5x size multiplier on top of damage-increased size.
- (Removed in Repentance) Sets Isaac's health to half a heart with each use (half a Soul Heart if these are present but there are no Red Heart containers). This also removes any other (Soul Heart) Soul Hearts or (Black Heart) Black Hearts, but not (Eternal Heart) Eternal Hearts.
- (Added in Afterbirth † / Removed in Repentance) If Isaac has no Red Hearts and at least one (Added in Afterbirth †) (Bone Heart) Bone Heart, only an empty Bone Heart remains.
- (Added in Repentance) Upon taking damage, this item turns into (Added in Repentance)
Broken Glass Cannon, and Isaac will lose an additional 2 hearts of health on top of the damage he already took. Isaac gains 1.5 range and leaves a trail of red creep behind him, identical to the effects of 
Anemic for the rest of the current room.
- If the damage from breaking Glass Cannon would result in death, Isaac will remain at half a heart, gaining half a soul heart if necessary. This does not apply if the damage Isaac took would be lethal before the extra damage is taken.
- Self-damage (e.g. from (Blood Donation Machine.png) Blood Donation Machines) will not break Glass Cannon.
Notes
-
Glass Cannon can be fired diagonally, even without (Added in Afterbirth †)
Analog Stick. -
Shooting the Glass Cannon gives a slight knockback effect to Isaac, which can be dangerous in rooms with obstacles like spikes or Fire Places.
-
Getting hit while playing (Keeper) Keeper will result into a second coin heart being damaged on top of the damage he already took.
Synergies
- (Added in Repentance)
Book of Virtues: Spawns white wisps on the middle ring. The wisps shatter in one hit and their tears deal 8 damage per shot, but if one of the wisps is destroyed, all the others are also destroyed. Does not affect wisps other than ones made by this item. Despite Glass Cannon having a timed charge, the wisps persist between rooms. 
Chocolate Milk: The current charge of Chocolate Milk affects Glass Cannon.- (Added in Afterbirth †)
Compound Fracture / 
Cricket's Body / 
The Parasite: Tears fired by Glass Cannon will split. 
Godhead: Creates a giant aura around Glass Cannon tears that almost fills up normal sized rooms.- (Added in Afterbirth †)
Lachryphagy: Glass Cannon will fire giant Lachryphagy tears. Tears are harder to feed as they will burst very quickly but they can be fed if you fire tears beforehand and then fire Glass Cannon into those tears. 
Multidimensional Baby: The Glass Cannon tears will be doubled by Multidimensional Baby.
Mysterious Liquid: Creates a large pool of creep when tears land.
Tiny Planet: Tears produced by Glass Cannon will orbit Isaac.
Interactions
- (Removed in Afterbirth †)
9 Volt, (Removed in Repentance) 
20/20, 
Anti-Gravity,
Car Battery, 
The Inner Eye, 
Mutant Spider, 
Brimstone, 
Dr. Fetus, 
Epic Fetus, 
The Ludovico Technique, 
Marked, 
Mom's Knife, 
Monstro's Lung, 
Technology, and 
Tech X: No effect, Glass Cannon fires a normal tear.
- (Added in Repentance)
Eye of the Occult: Cannon shot can be controlled. If a synergy is given a crosshair (e.g. Brimstone, Technology etc.), the tear will follow wherever it's pointed. 
Habit: Upon taking damage, (Added in Repentance) Broken Glass Cannon will be half-charged. However, taking damage before the last charge will break the cannon again.
Holy Mantle: Doesn't prevent damage done by Glass Cannon, but will protect against other types of damage.- (Removed in Repentance)
Ipecac: As the Glass Cannon tears are so large, even a modest damage increase or a single tear size increasing item is likely to render the tear unable to damage enemies, their explosions too far from them. - (Added in Repentance)
Pluto: Allows Isaac to cross small gaps using the knockback of Glass Cannon. - (Added in Afterbirth †)
Schoolbag: The cannon will break on damage, regardless if it or another active is on hand.
-
Tear Detonator: Glass Cannon shots will detonate into normal tears. The tears don't inherit spectral or piercing.
-
Soy Milk: Reduces damage of shots, no effect on charge time.- (Added in Afterbirth †)
Trisagion: Fires normal Trisagion beams that do not have increased damage. - (Added in Repentance)
The Wafer: Doesn't reduce the damage taken while Glass Cannon is held.