Dr. Fetus

Dr. Fetus is an unlockable passive item.

Effects

Tears are replaced with Bombs that explode approximately one second after being fired.
- Each bomb deals 3 times the character's normal tear damage.
- Each bomb deals 5 times the character's normal tear damage plus a flat 30 damage. The flat 30 is not affected by damage multipliers.
- Dr. Fetus has two formulas for calculating the damage it does. At first, each bomb deals 10 times the character's normal tear damage. If the previous formula would lead to the bombs doing more than 60 damage, the bombs instead deal 5 times the character's normal tear damage plus a 30 flat damage. The flat 30 is not affected by damage multipliers.
- Tears down: Tear Delay × 2.5 / Fire Rate ÷ 2.5.
- The range and shot speed stats both affect the velocity at which the bombs are fired out. Delay before the explosion is not affected by either.
  - Bomb velocity formula has not been updated to account for the new range stat so it uses tear height for calculation (and not the actual range stat), resulting in the range stat effectively not working for Dr. Fetus with exceptions being Number One, Kidney Stone, Pluto, and Inner Child's revive, which make velocity absurdly low. Shot speed still increases bomb velocity.
- Bombs grow larger or smaller with tear size modifiers and deal no knockback to each other.
  - The beams of Brimstone Bombs deal knockback to other bombs.

Notes

Dr. Fetus is a special item.
R U A Wizard? Does not affect Dr. Fetus.
Dr. Fetus overrides multiple tear effect items, but benefit from some ( but not all) bomb-enhancing effects like Mr. Mega.
- Many more synergies have been added, and all passive bomb modifiers affect Dr. Fetus.
Dr. Fetus bombs deal half a heart of damage to Isaac. Other explosion damage is not affected.
- Self-damage is increased to a full heart if the bomb would deal 85 damage or more. This includes effects from bomb modifiers, not just raw base damage.

Synergies

Apple! / Euthanasia: Damage multiplier may be applied to the non-flat damage without a visual difference.
- Euthanasia bombs do not retain the instant kill ability.
- Euthanasia bombs retain the instant kill ability.
Bob's Bladder: Bombs from Dr. Fetus leave creep, allowing for extra damage.
Bobby-Bomb: Bombs home in on enemies.
- Homing Tears: Bombs home in on enemies.
Bomber Boy: Bombs explode in a large cross-shaped pattern.
- Bomber Boy + Cricket's Body / The Parasite / Polyphemus / Scatter Bombs: The subsequent bomb or bombs explode in a cross-shaped pattern.
Blood Bombs: Bombs leave behind a pool of red creep.
Brimstone / Mom's Knife: Isaac continuously fires bombs while charging the beam/knife.
Brimstone Bombs: The activation rate of the Brimstone lasers is random and dependent on Luck. The chance is 11% at 0 Luck, increasing by 3% per luck. This maximizes at 100% at 29.67 luck and minimizes at 0% at -3.67 luck.
Butt Bombs: Bombs inherit the Butt Bomb effects.
- The activation rate is random and dependent on luck. The chance is 20% at 0 Luck, increasing by 3% per luck. This maximizes at 100% at 26.67 luck and minimizes at 0% at -6.67 luck.
- Unlike normal Butt Bombs, this synergy cannot heal Brownie, Clog, Colostomia, Dangle, or Dingle. Both the explosion and the cloud effect deal full damage.
Poisonous Tears : Fires Bob's Curse bombs.
Cricket's Body: The bombs split outwards into 4 tiny bombs, which detonate almost immediately.
- The split bombs deal a flat 21 damage / 35 damage.
- Increases range instead of decreasing it.
- Cricket's Body + The Parasite: Bombs split outwards into 4 Cricket bombs and 2 Parasite bombs, which detonate and split a second time into the other type, for a total of 23 explosions.
C Section: C Section has priority. Does not apply Dr. Fetus' tears down. The fetuses drop small bombs when they touch an enemy. The bomb's damage follows Dr. Fetus' damage calculation, based on half of the fetuses damage. A fetus can drop only one bomb.
- The fetuses' bombs do not benefit from Isaac's bomb effects such as Hot Bombs or Bobby-Bomb. However, they do benefit from Isaac's tear effects and have appearance of the corresponding bombs. For example, Hot Bombs from Fire Mind, Bobby-Bomb from Homing Tears. As such, Cricket's Body, The Parasite and Polyphemus leave a subsequent bomb or bombs, and Mysterious Liquid leaves a creep.
- C Section + Ipecac: The fetuses explode before dropping any bomb.
Dr. Fetus: Each additional copy of this item, such as from Diplopia / Crooked Penny, causes Isaac to fire one additional bomb in a side by side spread up to a maximum of 16 bombs. This maximum can’t be surpassed by other multi-shot effects such as 20/20.
Eye of Belial: Bombs get piercing. No more further effect.
- Bombs deal 2.5x piercing damage.
Fire Mind / Hot Bombs: The bombs leave behind a fire that damages enemies on contact after exploding, and bombs themselves deal 1 point of damage/ 16 damage on contact.
- For Hot Bombs, the activation rate of the fire is dependent on luck. The chance is 26% at 0 Luck, increasing by 6% per luck. This maximizes at 100% at 12.34 luck and minimizes at 0% at -4.34 luck.
- Fire Mind + Cricket's Body / Scatter Bombs: The fire spawned from split bombs can damage Isaac.
Ghost Bombs: Bombs gain spectral and create ghosts when they explode. The activation rate of the ghosts is dependent on luck. The chance is 34% at 0 Luck, increasing by 8% per luck. This maximizes at 100% at 8.25 luck and minimizes at 0% at -4.25 luck.
- Ghost Bombs + Almond Milk / Haemolacria / Monstro's Lung / Scatter Bombs / Soy Milk: While the bombs are mini, any created ghosts are smaller too and instantly launch themselves at enemies and explode, destroying nearby enemy tears, similar to Purgatory. They each deal 2x Isaac's damage, up to 4 times.
Godhead: Does not give bombs the damaging aura, but does give them the homing effect.
Guppy/The Mulligan: Explosions can spawn flies.
Haemolacria: Haemolacria has priority. Applies +10 Tear Delay after Haemolacria tears down, instead of Dr. Fetus tears down. The main tear is reminiscent of a bomb and scatters into 3-5 bombs that explode simultaneously. The split bombs deal half of Dr. Fetus' damage calculation based on the main tear's damage.
- Haemolacria + Sad Bombs: Sad bombs from Haemolacria tears shoot 10 Haemolacria tears, which then scatters into bombs without Sad Bombs' property.
Ipecac: The bombs become Bob's Curse bombs. Isaac is immune to his bomb shots (not explosives or placed bombs). Shots will also explode immediately on impact with enemies, rocks, Poops, angel statues, devil statues, or walls. Does not apply Ipecac's tears down.
- The damage is massively increased, as the +40 damage from Ipecac is run through the damage multiplier of Dr. Fetus.
- The effect on damage becomes a flat +2 bonus instead of +40. Bombs leave behind a cloud of poison gas that will poison enemies in contact with it.
- Ipecac + Cricket's Body / The Parasite / Polyphemus / Sad Bombs / Scatter Bombs: Isaac is immune to the main bomb shot, but not to the explosive shrapnel.
  - Isaac is immune to the shrapnel bombs left by Cricket's Body, The Parasite, Polyphemus, and Scatter Bombs. Isaac is not immune to Ipecac shots from Sad Bombs.
- Ipecac + Monstro's Lung: Isaac is no longer immune to his own bombs, and since they explode as soon as they make contact, it makes self-damage very likely. The flat damage bonus is increased to +40.
- Ipecac + Tech X: Isaac is immune to the main bomb shot, but not the explosions created by the laser ring.
Little Horn: Black-tinted bombs can summon Big Horn's hand to instantly kill non-boss enemies or to deal damage against bosses.
Monstro's Lung: Monstro's Lung has priority. Does not apply Dr. Fetus' tears down. Fires 6 bombs which detonate simultaneously.
- Monstro's Lung has priority. Does not apply Dr. Fetus' tears down. Fires 6 mini-bombs which detonate at different times.
- Multi-shot effects add 1 bomb to the barrage, up to 21 bombs.
Mr. Mega: Adds 25 flat damage to bomb explosions.
- The bonus damage is only applied if the bombs are visually Mr. Mega bombs, which means items like Soy Milk won't get the bonus damage.
Mysterious Liquid: Exploding bombs leave behind a large pool of creep.
The Parasite: Upon exploding, bombs split into two other bombs, which explode almost immediately.
- The split bombs deal a flat 24 damage/ 40 damage.
- The Parasite + Cricket's Body: Bombs split outwards into 2 Parasite bombs and 4 Cricket bombs, which detonate and split a second time into the other type, for a total of 23 explosions.
Piercing tears: Bombs deal 2.5x Isaac's damage to enemies when passing through them.
Poison tears: This is guaranteed by Bob's Curse, Ipecac, and Scorpio, and also has a chance to trigger from The Common Cold, Black Tooth, Pinky Eye or Serpent's Kiss.
- Poison bombs leave behind a cloud of toxic gas that will poison enemies in contact with it aside from the main target.
Polyphemus: The bombs increase in size and do increased damage.
- The bombs become Mr. Mega bombs. After they detonate, they leave behind a regular-sized bomb that deals a flat 60 damage/ 100 damage, much like a standard bomb.
Proptosis: Distance penalty does not apply.
- The non-flat damage for Dr. Fetus' damage calculation is doubled.
- The non-flat damage for Dr. Fetus' damage calculation is tripled.
Pyromaniac: Explosions heal Isaac, essentially making him invincible as long as he has at least one red heart container.
Remote Detonator: The bombs can be detonated on command, making it easier to hit moving enemies. Unlike placed bombs, they will eventually detonate on their own.
Rocket in a Jar: Shoots rockets.
- Piercing tears: Rockets do not pierce through enemies. However, they deal both piercing damage and explosion damage on impact with an enemy.
- Rocket in a Jar + Polyphemus: Rockets will “bounce” off of enemies, rocks, and walls, detonating twice. This is easily observable by firing parallel to a wall while moving towards it.
Sad Bombs: Fires tears as normally placed Sad Bombs would.
- The activation rate is random and dependent on luck. The chance is 11% at 0 Luck, increasing by 3% per luck. This maximizes at 100% at 29.67 luck and minimizes at 0% at -3.67 luck.
Scatter Bombs: The bombs split into 2-4/ 4-5 tiny bombs. The bombs deal half damage of the bomb it came from.
- The activation rate is random and dependent on luck. The chance is 34% at 0 Luck, increasing by 8% per luck. This maximizes at 100% at 8.25 luck and minimizes at 0% at -4.25 luck.
Technology: Both fire normally.
Tech X: Dr. Fetus has priority. The bombs have a laser ring around them.
- Tech X + Cricket's Body / The Parasite / Polyphemus / Scatter Bombs: The subsequent bomb or bombs do not have the laser ring.
Tough Love: Damage multiplier may be applied to the non-flat damage without a visual difference.
Uranus: The bombs freeze enemies upon killing them.

Interactions

Overridden by Dr. Fetus:

Only stat effects are applied; otherwise overridden by Dr. Fetus:

Other interactions:

Blasting Cap: Shot bombs cannot drop additional bombs.
Chocolate Milk: The bombs can't be charged, but reduces Isaac's tear delay by 20%.
Epic Fetus: Overrides Dr. Fetus.
Explosivo: The bombs have a chance of sticking to an enemy. These bombs have the same appearance as Sticky Bombs, but do not spawn spiders or slowing white creep.
Eye Sore: When Isaac shoots, he has a chance to fire 1-3 additional bombs in random directions.
The Forgotten/ Tainted Forgotten: A live bomb will spawn on top of The Forgotten when he starts charging his attack. The Forgotten will toss bombs after releasing the charge; airborne bombs deal 1.5x his damage if they collide with an enemy with enough speed. Max distance is obtained with minimal charge. If the bomb explodes while charging, a normal ranged bone attack happens after releasing it. The melee attack is unaffected.
Isaac's Tears: Fires normal tears.
Immaculate Heart: Orbital tears do not become bombs.
Kidney Stone / Number One / Pluto / Inner Child's revive: The bombs lose almost all of their range, and cannot be improved by range ups. Shot speed and tear height ups can be used to mitigate this downside.
Kidney Stone: The range decrease applies, but since the tear falling speed stat doesn't affect Dr. Fetus' bombs, they spawn directly in front of Isaac, making self-damage very likely. The effect can be mitigated with range ups.
Lead Pencil Every fifteenth shot will cause a barrage of short-ranged tears, which blocks the path of the bomb and can harm Isaac as the result.
The Ludovico Technique: The bomb can be controlled before exploding, similar to Epic Fetus. Isaac does not shoot bombs while controlling it.
- The Ludovico Technique + Almond Milk / Soy Milk: Since Isaac can't shoot bombs before they explode, this results in a damage down with no effective fire rate increase.
Marked: Isaac continuously fires bombs at the crosshair.
Monstro's Lung: Same effect as 20/20, except retains fire rate.
Mom's Eye: Grants a chance to shoot an extra bomb from the back of Isaac's head.
- Mom's Eye + Eye of the Occult: Bombs that spawn from Mom's Eye will try to move to where you're shooting making it very difficult to not get hit by your own explosions.
Mom's Knife: Overrides Dr. Fetus.
My Reflection: The bombs lose momentum and slide back towards Isaac, making self-damage very likely.
Ouroboros Worm: Does not affect the trajectory of the bombs. Turns some bombs into homing bombs, similar to Bobby-Bomb.
Parasitoid: Bomb explosions have a chance of leaving the slowing creep in a larger pool than egg sack tears, however the egg sack bombs can't spawn Blue Flies/Blue Spiders.
Piercing tears: The bombs pierce through enemies, which makes killing them more difficult.
Soy Milk: Rapidly shoots very low damage bombs. Can create a line of bombs which can knock each other back, which can be difficult to avoid taking damage from.
- Rapidly shoots medium damage bombs. Can create a line of bombs which can knock each other back, which can be difficult to avoid taking damage from.
- Rapidly shoots low damage mini-bombs. Bombs don't knock each other back.
Spectral tears: The bombs can pierce through the obstacles. If a bomb is fired inside an obstacle, the bomb collides against it, but not against others.
Spirit Sword: Overrides Dr. Fetus.
- Spirit Sword + Haemolacria: The split bombs can appear from Spirit Sword's projectiles.
Sticky Bombs: The bombs stick to enemies ( unless Isaac has piercing), but enemies killed by the bomb will not spawn Blue Spiders.
- The bombs always spawn slowing white creep after exploding.
Tear Detonator: No effect on bombs.
Tear height ups such as Tape Worm, Jupiter, Telepathy For Dummies, I - The Magician, and Huge Growth: Improves the effective range of the bombs.
Technology 2: The bombs are pushed forward by the laser.
Technology Zero: Dr. Fetus bombs do not generate electricity. Tears from other sources such as Sad Bombs can still generate electricity.
The Wiz: Causes Isaac to fire two bombs instead of one in diagonal directions.
Tiny Planet: The bombs fly uncontrollably around the player, making self-damage very likely.
Tractor Beam: After firing a bomb and moving, the bomb will have a homing-style effect towards the beam, but will not stay directly on the beam. Not recommended, as changing directions while firing will cause the bomb to reel back to Isaac at high speed, making self-damage very likely.

In-game Footage

Trivia

The Dr. Fetus and Epic Fetus items are based on Dr. Fetus, the main villain in Super Meat Boy, which is a game by Edmund McMillen (the creator of The Binding of Isaac: Rebirth).
- This is also the reason why taking the item replaces tears with bombs (Dr. Fetus fires rockets in chapter 6's bossfight in Super Meat Boy), and gives Isaac a top hat and a monocle (Dr. Fetus has a top hat and a monocle in Super Meat Boy).
This item is used in Demo Man (challenge #9).
In the original The Binding of Isaac, Dr. Fetus was unlocked by beating Mom's Heart five times instead of nine.

Gallery

Dr. Fetus in ending 9.

Bugs

Bug!	The black ring generated from the synergy of Dr. Fetus and Tech X behaves as a Maw Of The Void ring and may cause Black Hearts to drop.

Bug!	Even though having spectral tears will make bombs not collide with obstacles, if Isaac shoots a bomb while on top of an obstacle, the bomb will collide with it, making it possible to take damage.