Isaac's tears are replaced with guided missiles. Pressing the fire buttons spawns a crosshair that can be moved freely, dropping a missile on its position from above 1.5 seconds later.
Missiles deal 20 times Isaac's damage.
Isaac's tear delay determines how quickly a new missile can be fired after the previous one has landed.
Epic Fetus overrides most items in the game and has the highest priority of all tear modifiers, over Brimstone and Mom's Knife.
Missiles benefit from some bomb modifier items, though at a lesser scale compared to Dr. Fetus.
Stacking multiple copies of the item causes a barrage of missiles in quick succession without resetting the crosshair's position, up to sixteen at a time.
Missiles deal a full heart of damage to Isaac if they deal 85 or more damage.
Bomber Boy: Missiles explode in a large cross-shaped blast, with each explosion dealing 0.75x times damage. Unlike with regular bombs, getting hit by every separate explosion from Epic Fetus won't decrease the damage for each successive explosion, drastically increasing damage.
Blood Bombs: Every missile explosion leaves a large, lasting pool of red creep.
Blood Clot/Chemical Peel: Each missile has a 50% chance to deal 20 or 40 points more damage, respectively.
Explosions leave behind a cloud of poison gas that will poison enemies in contact with it aside from the main target.
Brimstone: Missile explosions shoot ten blood lasers in all directions.
Brimstone Bombs: Missile explosions have a chance to shoot four Brimstone lasers in the cardinal directions. The chance scales with Isaac's luck.
Butt Bombs: Missile explosions will cloud up the screen, briefly confusing and dealing 10 damage to all enemies in the room.
Eye Sore: More marks appear orbiting around where you're aiming.
Fire Mind/Hot Bombs: Missile explosions leave behind a fire that damage enemies on contact. Fire Mind's burn effect is overridden.
The Forgotten: The charge attack is replaced by a missile in the Forgotten's hand and a crosshair that may be moved for an indefinite amount of time. The missile is thrown at the crosshair when all attack buttons are released, with an additional melee swing in the same direction. The melee attack is unaffected.
Glitter Bombs: Missile explosions have a small chance of spawning pickups.
Homing tears: The crosshair slowly slides towards enemies.
Incubus: Incubus fires a missile alongside Isaac's.
Ipecac: Missiles have a poison effect, have a larger blast radius and deal drastically increased damage, as the +40 damage from Ipecac is run through the damage multiplier of Epic Fetus.
Adds flat +2 damage instead of +40. Explosions leave behind a cloud of poison gas that will poison enemies in contact with it aside from the main target.
Lil Clot / Tainted Eve: The clots have their own targeting reticles and fire simultaneously with Isaac.
Mom's Knife: Missile explosions shoot a ring of ten knives.
With a second Mom's Knife a second missile will be shot similar to 20/20.
Monstro's Lung: 2 to 4 additional crosshairs orbit the main crosshair, and missiles are fired onto each crosshair.
Mysterious Liquid: Every missile explosion leaves a small, lasting pool of creep.
Nancy Bombs: Explosions have a chance to be affected by any of the bomb-modifier effects that synergize with Epic Fetus.
Polyphemus: Increased tear delay, but massively increases the missiles' blast radius and damage, as Polyphemus' damage multiplier is run through the damage multiplier of Epic Fetus.
Sad Bombs: Missile explosions fire ten tears in all directions. The shrapnel's damage is not run through the damage multiplier of Epic Fetus.
The chance for the effect to proc is dependent of Isaac's luck. Chance goes up to 100% at 30 luck.
Sticky Bombs: Missile explosions leave a puddle of slowing white creep.
Loki's Horns: Adds a chance to spawn four crosshairs in cardinal directions. Isaac controls one and the others will mirror the movement keeping their space.
Marked: Continuously fires missiles at the marked spot.
If the crosshair is dismissed before the next missile is dropped, it still drops in the crosshair’s last position.
Soy Milk: Not recommended. Damage of missiles is drastically reduced, and unlike normal tears, the fire rate will not significantly increase.
Spirit Sword: Overrides Epic Fetus, making it the only item in the game that takes priority over Epic Fetus.
The Wiz: Makes two missiles drop in quick succession, and control of the crosshair is rotated 45 degrees clockwise. Not recommended, as it makes controlling the crosshair harder. However, mouse control is less affected.
Twisted Pair: Each familiar will fire a missile from a two additional crosshairs. Not Recommended, as the twisted pair crosshairs are not synced to Isaac's crosshair and move at a much slower rate, making self damage much more likely as the additional crosshairs will struggle to make distance from Isaac.
This item is similar to Doctor's Remote, except it's for every tears of Isaac and not an active item.
In the original game it was possible to control the crosshair with the mouse. This was removed in Rebirth.
Mouse control can however be re-enabled by editing the options.ini file in C:\Users\<username>\Documents\My Games\Binding of Isaac Afterbirth/Rebirth and changing the line MouseControl=0 into MouseControl=1. Also useful for The Ludovico Technique.
The Dr. Fetus and Epic Fetus items are based off of Dr. Fetus, the main villain in Super Meat Boy which is a game by Edmund McMillen (the creator of The Binding of Isaac: Rebirth).
In Wrath of the Lamb, Epic Fetus could be found in both the Secret Room and Treasure Room item pools.
Epic Fetus was added to the Secret Room item pool.
This item is used in Glass Cannon (challenge #11).
In Wrath of the Lamb, this item was originally unlocked by beating a challenge titled, "The Doctor's Revenge!".
Epic Fetus is a special item.
Brimstone and 
Mom's Knife.
Dr. Fetus.
20/20/ 
Conjoined/
Bookworm/
Mutant Spider/
The Inner Eye: Fires a barrage of missiles corresponding with the amount of tears.
Bomber Boy: Missiles explode in a large cross-shaped blast, with each explosion dealing 0.75x times damage. Unlike with regular bombs, getting hit by every separate explosion from Epic Fetus won't decrease the damage for each successive explosion, drastically increasing damage.
Blood Bombs: Every missile explosion leaves a large, lasting pool of red creep.
Blood Clot/
Chemical Peel: Each missile has a 50% chance to deal 20 or 40 points more damage, respectively.
Bob's Curse, 
Ipecac, and 
Scorpio, and also has a chance to trigger from 
The Common Cold, 
Pinky Eye or 
Serpent's Kiss.
Brimstone Bombs: Missile explosions have a chance to shoot four Brimstone lasers in the cardinal directions. The chance scales with Isaac's luck.
Butt Bombs: Missile explosions will cloud up the screen, briefly confusing and dealing 10 damage to all enemies in the room.
Eye Sore: More marks appear orbiting around where you're aiming.
Fire Mind/
Hot Bombs: Missile explosions leave behind a fire that damage enemies on contact. Fire Mind's burn effect is overridden.
The Forgotten: The charge attack is replaced by a missile in the Forgotten's hand and a crosshair that may be moved for an indefinite amount of time. The missile is thrown at the crosshair when all attack buttons are released, with an additional melee swing in the same direction. The melee attack is unaffected.
Glitter Bombs: Missile explosions have a small chance of spawning pickups.
Host Hat/
Pyromaniac: Isaac becomes immune to his own airstrikes.
Incubus: Incubus fires a missile alongside Isaac's.
Lil Clot / 
Tainted Eve: The clots have their own targeting reticles and fire simultaneously with Isaac.
Monstro's Lung: 2 to 4 additional crosshairs orbit the main crosshair, and missiles are fired onto each crosshair.
Mysterious Liquid: Every missile explosion leaves a small, lasting pool of creep.
Nancy Bombs: Explosions have a chance to be affected by any of the bomb-modifier effects that synergize with Epic Fetus.
Polyphemus: Increased tear delay, but massively increases the missiles' blast radius and damage, as Polyphemus' damage multiplier is run through the damage multiplier of Epic Fetus.
Sad Bombs: Missile explosions fire ten tears in all directions. The shrapnel's damage is not run through the damage multiplier of Epic Fetus.
Sticky Bombs: Missile explosions leave a puddle of slowing white creep.
Missiles also spawn Blue Spiders and Blue Flies upon damaging an enemy.
Strange Attractor: Enemies, pickups and trinkets get drawn towards the crosshair.
Technology: Both fire normally and the missile explosions shoot ten Technology beams in all directions.
Technology 2: Both fire normally.
Tech X: Missile explosions shoot ten Technology beams in all directions.
Azazel's default attack
Chocolate Milk
C Section, Epic Fetus is the only item in the game that can override it
Cursed Eye
Evil Eye
Godhead
Jacob's Ladder
The Ludovico Technique
Mucormycosis
Neptunus
The Parasite
Sinus Infection
Tainted Azazel's default attack
Technology Zero
Tiny Planet
Trisagion
Anti-Gravity
Eye of the Occult
8 Inch Nails: Missile explosions retain the knockback boost, so enemies that survive the blast will be knocked back far.
Bobby-Bomb/
Ghost Bombs/
Mr. Mega/
Scatter Bombs: No effect.
Isaac's Tears:
It Hurts/
Tammy's Head/
Varicose Veins: Fires only normal tears, not missiles.
Loki's Horns: Adds a chance to spawn four crosshairs in cardinal directions. Isaac controls one and the others will mirror the movement keeping their space.
Marked: Continuously fires missiles at the marked spot.
Soy Milk: Not recommended. Damage of missiles is drastically reduced, and unlike normal tears, the fire rate will not significantly increase.
Spirit Sword: Overrides Epic Fetus, making it the only item in the game that takes priority over Epic Fetus.
The Wiz: Makes two missiles drop in quick succession, and control of the crosshair is rotated 45 degrees clockwise. Not recommended, as it makes controlling the crosshair harder. However, mouse control is less affected.
Twisted Pair: Each familiar will fire a missile from a two additional crosshairs. Not Recommended, as the twisted pair crosshairs are not synced to Isaac's crosshair and move at a much slower rate, making self damage much more likely as the additional crosshairs will struggle to make distance from Isaac.
Doctor's Remote, except it's for every tears of Isaac and not an active item.
The Binding of Isaac: Rebirth
