For changes to Rebirth monsters, see Changes.

Monsters refers to the many antagonistic creatures the player will encounter throughout the game. Antibirth adds over 80 new monsters, many of which are found in the new Chapters.

Monster List[ | ]

Monster	Description
Dumpling	Flies around and farts if Isaac is close, if it is damaged, and when it dies. Farts knock Isaac back and propel it forwards.
Skinling	Similar behavior to Dumplings, but its farts are poisonous.
Scab	Flies towards Isaac. Upon death, farts and sends out 6 blood shots in all directions.
Fissure	Jumps towards Isaac like a Trite. When it jumps, it fires a red shot towards Isaac. Occasionally, it stands still and spews a chaotic burst of red shots.
Soi Creep	Crawls along walls to try to line up with Isaac and rapidly fires white tears in a straight line.
Grilled Clotty	Randomly wanders around the room, frequently firing four blood shots at a slight angle.
Blind Bat	Starts out asleep. When Isaac gets close, it wakes up and chases Isaac, followed by a group of three more Blind Bats.
Floating Host	Flies around the room diagonally and is normally invulnerable. Raises its head up occasionally, revealing a fleshy stem that can be damaged.
Blurb	Walks towards Isaac and fires a chaotic burst of tears if they get close. After firing their tears, they act like regular Gapers and chase Isaac, attempting to deal contact damage.
Prey	Runs away from Isaac and periodically spawns Small Leeches. Spawns more Small Leeches upon death.
Sub Horf	Rotates and fires tears upon taking damage.
Bubbles	Slowly walks towards Isaac, occasionally firing a tear at Isaac when damaged. Upon death, bursts into a fountain of tears.
Tidal Gaper	Pops out of the water and chases Isaac. Has a chance to spawn with a Small Leech attached, which will detach when the Gaper is killed.
Small Leech	Swims towards Isaac, and can travel across gaps.
Strider	Swims towards Isaac in small bursts, and can travel across gaps.
Wraith	Chases Isaac. Invisible; detectable only by its reflection and the ripples in the water, and the occasional lightning that makes them briefly visible.
Willo	Orbits Isaac, periodically firing orange shots inwards.
Mullighoul	Runs away from Isaac, occasionally spawning a Willo. Spawns a Willo upon death.
Polty	Appears out of a random bucket, then picks up and throws obstacles at Isaac. If the room has no usable obstacles, it will leave the room. If there are any Tinted Rocks in the room, it will wait until they are the last remaining obstacle, then attempt to flee with one of them.
Blaster	Runs away from Isaac and fires Fly Bombs.
Bouncer	Runs away from Isaac. If Isaac gets close, its head inflates and it starts chasing Isaac. Releases a chaotic burst of red shots upon death.
Coal Boy	Walks towards Isaac, periodically firing several hot rocks towards Isaac, some of which may be Coal Spiders. Hot coals linger and can hurt Isaac.
Rock Spider	Skitters towards Isaac when he's close, and may turn into a normal Spider upon death.
Tinted Rock Spider	Skitters towards Isaac when he's close, and drops a Soul Heart upon death.
Coal Spider	Erratically moves around when Isaac is close. Leaves behind hot coals upon death that can hurt Isaac.
Danny	Walks towards Isaac, periodically firing several rocks towards Isaac, some of which may be Rock Spiders.
Dragonfly	Flies around the room diagonally. Upon death, releases fire in either the cardinal or diagonal directions, depending on the appearance of its eyes.
Echo Bat	Flies towards Isaac and periodically fires three white orbs. If an orb hits Isaac, he becomes confused and his movement is reversed for a few seconds.
Faceless	Wanders aimlessly and fires tears in six directions. If Isaac gets close, it will start chasing him.
Fanatic	Chases Isaac, shooting homing tears periodically. Present in the Heretic fight.
Fireworm	Pops out of a hole in the ground and spits fire at Isaac. The fire persists for a while, and can be put out by shooting it. Only present when there's lava in the room.
Fly Bomb	Flies towards Isaac. Turns into a small bomb on death that explodes after a short delay.
Gyro	Rolls around aimlessly. If Isaac gets close, it starts rapidly rolling towards him.
Grilled Gyro	Rolls around aimlessly. If Isaac gets close, it starts rapidly rolling towards him, and leaves fires on the ground.
Hard Host	Stationary enemy that is normally invulnerable. Raises its head up when Isaac gets close, revealing a fleshy stem that can be damaged. After a short delay, it slams its head down, sending a rock wave towards Isaac.
Hardy	Charges at the player until it runs into a wall or obstacle. Upon impact, rocks are fired in all directions, with a chance to make rocks fall from the ceiling. Self-destructs after the third impact. Spawns a Dip upon death.
Ink	Flies towards Isaac. Upon death, fires four black shots in the diagonal directions and leaves a pool of slowing black creep.
Mole	Slowly digs underground towards Isaac. When they get close, they pop up and fire three blood shots at Isaac.
Quakey	Walks towards Isaac, sometimes leaping forward, causing a ring of rocks to spread from the landing, and making rocks fall from the ceiling.
Bomb Grimace	Spawns Red Bombs for Isaac to use.
Quake Grimace	Periodically fires a rock wave forwards. Does not stop, even if the room is cleared.
Bishop	Stationary enemy that protects any nearby enemies from damage.
Black Knight	Moves erratically around the room and charges toward Isaac when in line of sight. Can only be damaged from behind. Tears that hit its front are reflected and can damage Isaac.
Big Bony	Slowly walks towards Isaac. Occasionally fires a large bone which creates rock waves near its point of impact.
Candler	Bounces around the room diagonally. Occasionally pauses and creates a small fire underneath itself.
Corpse Eater	Rapidly moves around the room erratically and charges at Isaac if he comes within its line of sight.
Carrion Rider	Rapidly moves around the room erratically and charges at Isaac if he comes within its line of sight. The Bony on its back shoots at Isaac.
Cursed Globin	Chases Isaac, dealing a full heart of contact damage. Upon taking enough damage, it collapses into two piles of goo, which can be killed. Both piles can regenerate after a short period of time if not killed quickly.
Loose Knight	Moves erratically around the room and can only be damaged from behind. Splits into an Empty Knight and a Pon upon death.
Empty Knight	Moves erratically around the room and charges toward Isaac when in line of sight. Cannot be damaged, but will die if the corresponding Pon is killed.
Pon	Hops around the room, leaving pools of damaging red creep.
Exorcist	Summons ghost enemies such as Wizoobs, Lil' Haunts, and Candlers.
Whipper	Moves around the room and charges at Isaac if he gets within its line of sight. If Isaac gets close, it lashes out with a short-ranged whip, which can damage Isaac and deflect projectiles.
Lunatic	Moves around the room and charges at Isaac if he gets within its line of sight. Constantly lashes out with its whip.
Snapper	Moves around the room and charges at Isaac if he gets within its line of sight. If Isaac lines up with it horizontally or vertically, it lashes out with a long-range whip which can damage Isaac.
Necromancer	Summons skeleton enemies such as Bonies and Big Bonies.
Nightwatch	Invulnerable enemies. Moves in a fixed pattern or rotates in a spot. If Isaac enters its light, it will lock all doors, summon enemies, and vanish.
Revenant	Moves erratically. If Isaac gets near, it becomes stationary and starts breathing a stream of purple fire at Isaac.
Screamer	Walks slowly around the room. If Isaac gets too close, it will scream, paralyzing Isaac. It will gain a slowing aura and start charging towards him.
Smoky	Bounces around the room with a purple aura. If Isaac touches an aura, he will briefly become afraid, unable to fire tears. Dies when the room is cleared.
Strifer	Walks horizontally or vertically, attempting to line up with Isaac. Frequently fires lines of four tears forwards.
Swapper	Slowly floats towards Isaac and fires purple lasers. Occasionally teleports and reappears elsewhere. Has a chance to swap positions with Isaac.
Vis Versa	Charges and fires a curving Brimstone laser when Isaac gets in its line of sight.
Adult Leech	Charges towards Isaac when he's in their line of sight, and burrows in the ground to either pop out the side of the wall or the ceiling.
Barfy	Wanders around the room, and slowly follows Isaac when he's in its line of sight. Occasionally spews clusters of green shots towards Isaac.
Cohort	Hops around, occasionally stopping to spew out a cluster of blood shots at Isaac. Upon death, spawns four Globins.
Coil	Creates beams of electricity to other enemies in the room. Touching the electricity damages Isaac. Cannot be killed.
Cyst	Attaches itself to a wall or obstacle and rolls around it while periodically firing blood shots at Isaac.
Evis	Spits outs its guts, which latch onto Isaac, dealing no damage but slowly drawing Isaac closer to it, impeding movement.
Gasbag	Continuously creates a gas cloud around them.
Mama Fly	Lays Pustules on the ground. Explodes into Small Maggots when killed.
Pustule	Grows until it bursts into Small Maggots, and leaves a small puddle of green creep.
Rotten Gaper	Chases down Isaac, and may explode into Small Maggots.
Sick Boom Fly	Flies around the room diagonally. Upon death, creates a large poison cloud.
Small Maggot	Slowly crawls around the room randomly.
Spikeball	Travels back and forth in a straight line across a room. Cannot be killed.
Stillborn	Slowly floats towards Isaac, occasionally firing blood shots. Cannot be killed and dies when the room is cleared.
Twitchy	Alternates between chasing Isaac and leaping at him.
Vessel	Walks around the room and explodes into Small Maggots upon death.
Unborn	Spins and floats around the room towards Isaac, and can teleport randomly.