Binding of Isaac: Rebirth Wiki
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Binding of Isaac: Rebirth Wiki

Utero is an alternate floor to Womb Womb. Unlike other alternate floors, Utero does not need to be unlocked, aside from unlocking The Womb. While the theme of Utero overlaps heavily with The Womb, it appears to emphasize gore and disfigurement rather than its counterpart's focus on 'intact' viscera, though the difference in enemy make-up is still more subtle compared to other floors nonetheless. Its walls are slightly different, and the floor contains several new enemies that are bloodier and more deformed, as well as more enemies borrowed from later chapters such as Cathedral Cathedral and Sheol Sheol.

Like The Womb, all damage that is taken on this floor and onwards deducts a full heart from the player's health (unless the player has 15►The Wafer The Wafer), regardless of the source. Added in Repentance While in the Utero, a dark yellowish desaturated screen shader and a warping effect will be applied to the screen, making it appear as if the area is submerged in fluid and further distinguishing the floor's appearance from The Womb.

Monsters[]

Entity ID Description
Baby
Baby
38.0 Slowly floats towards Isaac and fires a blood shot at him. Occasionally teleports and reappears elsewhere.
Angelic Baby
Angelic Baby
38.1.0 Slowly floats towards Isaac and fires three spread shots. Occasionally teleports and reappears elsewhere.
Boil
Boil
30.0 Stationary enemy that decreases in size when hit, but regenerates to its full size until fully destroyed. Fires multiple short-ranged blood projectiles in random directions when fully swollen.
Walking Boil
Walking Boil
88.0 Does not shrink or regenerate. Walks around aimlessly and fires multiple short-ranged blood projectiles in random directions.
Bony
Bony
227.0 Wanders around the room and throws a bone at Isaac when he is in sight.
Death's Head
Death's Head
212.0 Invulnerable enemy that moves diagonally around the room, dealing contact damage. Dies when the room is cleared.
Brain
Brain
32.0 Slowly crawls around the room, leaving a trail of Red Creep.
MemBrain
MemBrain
57.0 Slowly moves around the room, occasionally hopping and firing 8 large blood shots in all directions. Splits into 2 Brains upon death.
Clotty
Clotty
15.0 Randomly wanders around the room, firing 4 blood shots in the cardinal directions.
Clot
Clot
15.1 Randomly wanders around the room, firing 4 tar shots in the ordinal directions.
I.Blob
I.Blob
15.2 Randomly wanders around the room, firing 8 shots in all directions.
Dip
Dip
217.0 Slowly dashes in random directions, dealing contact damage.
Squirt
Squirt
220.0 Dashes towards Isaac and deals contact damage. Spawns 2 Dips upon death.
Dinga
Dinga
223.0 Slowly moves around the room, occasionally hopping to spawn Dips or fire 8 Brown shots in all directions. Splits 2 Squirts upon death.
Dople
Dople
53.0 Mirrors Isaac's movements and fires blood shots at the same time as Isaac. Can be damaged by spikes.
Embryo
Embryo
77.0 Aimlessly hops around the room, dealing contact damage.
Eye
Eye
60.0 Slowly turns towards Isaac and fires a Technology laser at Isaac if he stands still or is too slow.
Bloodshot Eye
Bloodshot Eye
60.1 Slowly turns towards Isaac and fires a Brimstone beam at Isaac if he stands still or is too slow.
Pale Fatty
Pale Fatty
208.2 Slowly walks towards Isaac. Occasionally farts and shoots 6 blood shots in all directions. Has a chance to turn into a Blubber or Half Sack upon death.
Fat Sack
Fat Sack
209.0 Slowly walks towards Isaac. Occasionally leaps off-screen and attempts to land on Isaac, leaving a puddle of Red Creep and shooting 6 blood shots in all directions where it lands. Has a chance to turn into a Blubber or Half Sack upon death.
Blubber
Blubber
210.0 Walks around aimlessly and randomly spews a cluster of blood shots in all directions. Has a chance to turn into a Half Sack when killed.
Half Sack
Half Sack
211.0 Wanders around aimlessly and leaves a trail of Red Creep.
Fly
Fly
13.0 Hovers in place. Does not deal contact damage and is harmless but can turn into Pooters if they stay around Poop.
Eternal Fly
Eternal Fly
96.0 Invulnerable fly that circles Corny Poop and various monsters. Deals contact damage. Turns into a vulnerable Attack Fly after the object or monster it circles is destroyed.
Moter
Moter
80.0 Follows Isaac, similar to Attack Flies. Deals contact damage. Splits into 2 Attack Flies upon death.
Pooter
Pooter
14.0 Slowly drifts toward Isaac, occasionally firing a single blood shot at him. Does not deal contact damage.
Super Pooter
Super Pooter
14.1 Slowly drifts toward Isaac, occasionally firing two blood shots in a V-formation at him. Does not deal contact damage.
Full Fly
Full Fly
249.0 Flies toward Isaac erratically, dealing contact damage. Releases 6 bullets in all directions upon death.
Red Boom Fly
Red Boom Fly
25.1 Flies around the room diagonally, dealing contact damage. Creates a ring of 6 blood shots upon death.
Sucker
Sucker
61.0 Flies slowly towards Isaac, exploding into 4 shots in the cardinal directions upon death.
Spit
Spit
61.1 Flies slowly towards Isaac, firing an Ipecac shot towards Isaac upon death.
Fred
Fred
59.0 Hops out of the ground and burrows elsewhere, firing 4 blood shots in the ordinal directions. Occasionally fires red Ipecac shots at Isaac.
Globin
Globin
24.0 Chases Isaac, dealing a full heart of contact damage. Upon taking enough damage, it collapses into a pile of goo, which can be killed. Will regenerate after a short period of time if not killed quickly.
Gazing Globin
Gazing Globin
24.1 Quickly chases Isaac, dealing a full heart of contact damage. Upon taking enough damage, it collapses into a pile of goo, which will slide away from Isaac and can be killed. Will regenerate after a short period of time if not killed quickly.
Grub
Grub
239.0 Erratically moves around the room like Larry Jr. and charges at Isaac when he gets within its line of sight. Spawns Maggots, Chargers, or Spitties upon death, one for each of its segments.
Gurgling
Gurgling
237.0 Charges towards Isaac when he lines up with them, leaving a trail of Red Creep and shooting 6 blood shots.
Guts
Guts
40.0 Attaches itself to a wall or obstacle and rolls around it.
Mama Guts
Mama Guts
57.1 Slowly moves around the room, occasionally hopping and firing 8 large blood shots in all directions. Splits into 2 Guts upon death.
Homunculus
Homunculus
228.0 Starts attached to the wall or an Added in Afterbirth † obstacle. After a while, it detaches, shooting 6 blood shots in all directions, leaving a puddle of Red Creep and chasing Isaac. If it dies while still attached, it will still leave a puddle of Red Creep.
Leech
Leech
55.0 Quickly charges towards Isaac when he gets in its line of sight.
Holy Leech
Holy Leech
55.2 Quickly charges towards Isaac when he gets in its line of sight. Explodes upon death. Spawns with an Eternal Fly circling it, which instantly dies when the Holy Leech explodes.
Lump
Lump
56.0 Fires 3 spread blood shots at Isaac when he gets in its line of sight. Will burrow underground and reappear elsewhere after firing.
Charger
Charger
23.0 Slowly moves around the room, charging at Isaac when he gets in its line of sight.
Mask + Heart
Mask + Heart
92.0 The Mask is invulnerable and moves around erratically, charging at Isaac when he lines up with it. The Heart avoids Isaac and fires 4 blood shots in the cardinal directions when Isaac gets near. Killing the Heart will automatically kill the Mask.
Knight
Knight
41.0 Moves erratically around the room and charges towards Isaac when in line of sight. Can only be damaged from behind.
Maw
Maw
26.0 Slowly floats towards Isaac, firing blood shots at him when he is in their range.
Red Maw
Red Maw
26.1 Floats towards Isaac and releases 4 blood shots in the cardinal directions upon death.
Psychic Maw
Psychic Maw
26.2 Slowly floats towards Isaac, firing homing shots at him when he is in their range. Spawns with an Eternal Fly orbiting around it.
Mr. Maw
Mr. Maw
35.0 Walks towards Isaac and attacks by launching its head towards him. Turns into a Maw or Gusher upon death depending on the killed body segment. Occasionally separates at will.
Mom's Hand
Mom's Hand
213.0 Falls from the ceiling. If it lands on Isaac, it deals damage and teleports the player back to the spawn room of the floor. Entering a room containing Mom's Hand will warn the player with Mom's laugh.
Swinger
Swinger
216.0 Slowly moves towards Isaac as its head swings around its base. Upon death, spawns a Maw or a Globin depending on which part is killed.
Nerve Ending
Nerve Ending
231.0 Static enemy which acts as a meat shield.
Oob
Oob
224.0 When Isaac lines up with it horizontally, it charges across the room once. When Isaac is not horizontal to it, it spawns Brains.
Para-Bite
Para-Bite
58.0 Moves towards Isaac, dealing contact damage. Can burrow underground and reappear elsewhere.
Cod Worm
Cod Worm
221.0 Stationary enemy that hides in a shell and spews a burst of blood shots if shot at. Only vulnerable when it pops its head out.
Red Host
Red Host
27.1 Stationary enemy that can be damaged even when its head is lowered. Fire 5 spread blood shots when it raises its head.
Flesh Mobile Host
Flesh Mobile Host
247.0 Acts like the Red Host, but follows Isaac and deals contact damage.
Rotty
Rotty
226.1 Slowly walks towards Isaac, leaving short-lasting Red Creep behind itself. Spawns a Bony or two Attack Flies upon death.
Round Worm
Round Worm
244.0 Pops out of the ground in random locations and spits a blood shot at Isaac if he is in sight.
Spider
Spider
85.0 Erratically moves around the room. If Isaac gets close to it, it chases him, trying to deal contact damage.
Big Spider
Big Spider
94.0 Erratically moves around the room. If Isaac gets close to it, it chases him, trying to deal contact damage. Spawns two Spiders upon death.
Crazy Long Legs
Crazy Long Legs
207.0 Chases Isaac, dealing touch damage. Occasionally stops to spit 8 blood shots in all directions.
Small Crazy Long Legs
Small Crazy Long Legs
207.1 Chases Isaac, dealing touch damage. Occasionally stops to spit 4 blood shots in the diagonal directions.
Wall Creep
Wall Creep
240.0 Crawls along walls to try to line up with Isaac and shoots three blood shots in a line.
Blind Creep
Blind Creep
242.0 Randomly crawls along walls and shoots three spread blood shots.
Rage Creep
Rage Creep
241.0 Slowly crawls along walls to try to line up with Isaac and shoots a Brimstone laser.
Tumor
Tumor
229.0 Moves around the room diagonally, occasionally firing 6 blood shots in all directions. Fires more often upon getting damaged.
Vis
Vis
39.0 Randomly wanders around the room. Pauses to charge and fire a Brimstone laser when Isaac gets in its line of sight.
Double Vis
Double Vis
39.1 Randomly wanders around the room. Pauses to charge and fire a Brimstone laser which fires from both sides when Isaac gets in its line of sight.
Chubber
Chubber
39.2 Randomly wanders around the room. Pauses to fire a Charger that deals one heart of damage when Isaac gets in its line of sight. The Charger is invulnerable, blocks Isaac's tears, has limited range, and flies back to the Chubber.
Wall Hugger
Wall Hugger
218.0 Moves around the room like Guts, damaging Isaac by contact. Cannot be destroyed.
Stone Grimace
Stone Grimace
42.0 Stationary and invulnerable monster that occasionally fires a blood shot at Isaac. Stops firing when room is cleared.
Vomit Grimace
Vomit Grimace
42.1 Stationary and invulnerable monster that occasionally fires an Ipecac shot at Isaac. Stops firing when room is cleared.
Constant Stone Shooter
Constant Stone Shooter
202.0 Stationary and invulnerable monster that continuously fires shots in a single direction.
Gaping Maw
Gaping Maw
235.0 Stationary and invulnerable monster that sucks Isaac towards it, along with Isaac's tears and enemy projectiles.
Broken Gaping Maw
Broken Gaping Maw
236.0 Stationary and invulnerable monster that sucks Isaac towards it, along with Isaac's tears and enemy projectiles. Alternates between active and inactive every couple of seconds. Has a stronger attraction power than a regular Gaping Maw.
Stone Eye
Stone Eye
201.0 Stationary and invulnerable monster that constantly rotates and fires a flickering Technology laser. Stops firing when the room is cleared.
Flesh Death's Head
Flesh Death's Head
Added in Afterbirth
286.0 Moves diagonally around the room, dealing contact damage. Releases 6 blood shots in all directions upon death. Can be killed, but also dies when the room is cleared.
Mega Clotty
Mega Clotty
Added in Afterbirth
282.0 Slowly moves around the room, occasionally hopping and either firing 6 blood shots in all directions, leaving a puddle of Red Creep, or spawning a Clotty or a collapsed Globin. Splits into two Clotties upon death.
Meatball
Meatball
Added in Afterbirth
290.0 Slides around the room. If Isaac is in sight, it will stop to spew a fountain of short-range blood shots in all directions or to spit a line of damaging Red Creep towards Isaac. Spawns a Host upon death.
Mom's Dead Hand
Mom's Dead Hand
Added in Afterbirth
287.0 Falls from the ceiling. Upon landing, it spawns several rock waves that travel outwards. Spawns several spiders upon death. Entering a room containing Mom's Dead Hand will warn the player with Mom's laugh.
Red Ghost
Red Ghost
Added in Afterbirth
285.0 Disappears, then reappears near Isaac and fires a brimstone laser.
Ulcer
Ulcer
Added in Afterbirth
289.0 Pops out of the ground in random locations and spawns a Dart Fly if Isaac is in sight. Fires a blood shot after spawning 6 Dart Flies.
Suction Pitfall
Suction Pitfall
Added in Afterbirth
291.2 Invulnerable and stationary enemy which sucks Isaac towards itself. Isaac falls into it when walked over, taking damage and popping back out after a short delay.
Blister
Blister
Added in Afterbirth †
303.0 Slowly hops towards Isaac, occasionally spawning a Dark Ball. Spawns a Sack upon death.
Poison Mind
Poison Mind
Added in Afterbirth †
301.0 Slowly crawls/floats around the room diagonally, leaving a trail of damaging green creep. Explodes upon death.
Mr. Red Maw
Mr. Red Maw
Added in Afterbirth †
35.2 Walks towards Isaac and attacks by launching its head towards him. Turns into a Red Maw or Gusher upon death depending on the killed body segment. Occasionally separates at will.
Nerve Ending 2
Nerve Ending 2
Added in Afterbirth †
231.1 Static enemy which whips at Isaac if he gets too close.
Cross Stone Shooter
Cross Stone Shooter
Added in Afterbirth †
202.10 Stationary and invulnerable monster that continuously fires shots in four directions, alternating between cardinal and ordinal.
Cohort
Cohort
Added in Repentance
857.0 Acts similarly to Monstro, hopping towards Isaac and can either spit a large projectile towards Isaac that bursts into 8 smaller projectiles or cough up a burst of arcing projectiles and a pile of Globin goo. Spawns 4 piles of Globin goo upon death.
Eggy
Eggy
Added in Repentance
29.2 Hops aimlessly around the room, spawning slowing white creep wherever it hops. Spawns a group of Swarm Spiders upon death.
Floating Host
Floating Host
Added in Repentance
859.0 Floats diagonally around the room and is normally invulnerable. When Isaac gets close, reveals a fleshy stem that can be damaged and fires 3 blood shots in an angle at him before hiding its stem again.
Wrinkly Baby
Wrinkly Baby
Added in Repentance
38.3 Lunges towards Isaac at high speed and fires three blood shots in his direction once stopped.
Needle
Needle
Added in Repentance
881.0 Pops out of the ground and lunges towards Isaac, dealing contact damage.
Peeping Fatty
Peeping Fatty
Added in Repentance
835.0 Has two indestructible eyeballs that are out of their sockets but attached by muscles. Wanders around the room randomly, or toward Isaac if its eyes see him. Occasionally farts and fires a radial burst of 6 blood shots.
Planetoid
Planetoid
Added in Repentance
229.1 Moves around the room diagonally, occasionally firing blood shots that orbit itself. Fires more shots and has a chance to send its ring of shots outward upon taking damage.
Triple Grimace
Triple Grimace
Added in Repentance
42.2 Stationary and invulnerable monster that occasionally fires a triple shot at Isaac. Stops firing when room is cleared.
Degraded Bosses

Bosses[]

Boss Blastocyst.png
Boss The Bloat.png
Boss Daddy Long Legs.png
Boss Lokii.png
Blastocyst Removed in Repentance The Bloat Daddy Long Legs Lokii
Boss Mama Gurdy.png
Boss Mr. Fred.png
Boss Teratoma.png
Boss The Fallen.png
Mama Gurdy Removed in Repentance Mr. Fred Removed in Repentance Teratoma The Fallen Requires previous entry into a devil room
Boss Conquest.png
Boss Death.png
Boss The Headless Horseman.png
Boss Triachnid.png
Conquest Needs to be unlocked Death Needs to be unlocked The Headless Horseman Needs to be unlocked Triachnid Needs to be unlocked
Boss The Matriarch.png
Boss Sisters Vis.png
The Matriarch Added in Afterbirth † / Removed in Repentance Needs to be unlocked Sisters Vis Added in Afterbirth † Needs to be unlocked

Double Trouble[]

Double Trouble Bosses
Boss The Cage.png
Boss The Fallen.png
Boss The Gate.png
(Double Trouble)
The Cage
(Double Trouble)
The Fallen
(Double Trouble)
The Gate
Boss Gurdy.png
Boss Loki.png
Boss Little Horn.png
(Double Trouble)
Gurdy
(Double Trouble)
Loki
(Double Trouble)
Little Horn Added in Afterbirth Needs to be unlocked

Final Boss[]

Mom's Heart will always appear in the second floor of this chapter or in the last boss room if Curse of the Labyrinth is active. Once It Lives is unlocked, it will appear instead of Mom's Heart.

Boss Mom's Heart.png
Boss It Lives.png
Mom's Heart It Lives Needs to be unlocked

Unlockable Achievements[]

  • Mama's Boy
    Mama's Boy - Beat chapter 4 without taking damage.

Music[]

  • Removed in Repentance The music for Utero is titled Viscera. The term “viscera” refers to the internal organs in the body. Womb Womb shares this same track.
    • Added in Repentance The music for Utero is titled Caesarian. A caesarian is a medical procedure where a baby is surgically removed from the mother due to complications during birth.
  • The music heard during the fight against Mom's Heart/It Lives is called Ventricide. Ventricide is a word made up of the Latin word for Heart, Ventricle, and the suffix -cide, which denotes the act of killing.
    • This has been confirmed by Edmund when he said it means something like "the killing of the heart". This is in theme with other similar boss tracks such as Matricide, Hericide, and Infanticide.

Binding of Isaac: Rebirth OST


SmallIsaac.pngChaptersSmallIsaac.png
Chapter 1 Chapter 2 Chapter 3 Chapter 4 Optional Chapter 5 Chapter 6 Endgame
Normal and hard modes only Stage Basement icon.png Stage Caves icon.png Stage Depths icon.png Stage Womb icon.png Stage Sheol icon.png
Sheol


Stage Cathedral icon.png
Cathedral
Stage Dark Room icon.png
Dark Room


Stage Chest icon.png
The Chest
The Basement The Caves The Depths The Womb
Added in Afterbirth Added in Afterbirth †
Stage Cellar icon.png Stage Catacombs icon.png Stage Necropolis icon.png Stage Utero icon.png ??? Stage The Void icon.png
The Cellar The Catacombs Necropolis Utero ??? The Void
Added in Afterbirth Added in Afterbirth Added in Afterbirth Added in Afterbirth
Stage Burning Basement icon.png Stage Flooded Caves icon.png Stage Dank Depths icon.png Stage Scarred Womb icon.png
Burning Basement Flooded Caves Dank Depths Scarred Womb
Added in Repentance Added in Repentance Added in Repentance Added in Repentance Added in Repentance
Stage Downpour.png Stage Mines icon.png Stage Mausoleum icon.png Stage Corpse icon.png Stage Home icon.png
Downpour Mines Mausoleum Corpse Home
Added in Repentance Added in Repentance Added in Repentance
Stage Dross icon.png Stage Ashpit icon.png Stage Gehenna icon.png
Dross Ashpit Gehenna
Added in Afterbirth
Greed and greedier modes only
Added in Afterbirth Added in Afterbirth
Stage Basement icon.png Stage Caves icon.png Stage Depths icon.png Stage Womb icon.png Stage Sheol icon.png The Shop Ultra Greed
The Basement The Caves The Depths The Womb Sheol The Shop Ultra Greed
The Binding of Isaac: Rebirth The Binding of Isaac: Rebirth The Binding of Isaac: Rebirth
Achievements Achievements Attributes Attributes Bosses Bosses TarotCard.png Cards and Runes Challenges Challenges Chapters Chapters
Characters Characters MainPageBabies.png Co-op Items Items Item pools Item pools Monsters Monsters Objects Objects
Pickups Pickups Pills Pills Rooms Rooms Seeds Seeds Transformations Transformations Trinkets Trinkets