Monsters

Monsters are the main enemies encountered throughout The Binding of Isaac series.

Most monsters (with few exceptions) will damage Isaac by either touching him or shooting him with shots. Along with normal varieties of monsters, Champion versions of monsters can be found lurking about. These monsters are often like normal monsters, but have a color tint or size change and drop basic Pick Ups (or rarely, a Chest) upon death. There are also Champion versions of Bosses.

Monster List[]

Monster	Description	Eternal Variant (Hard Mode only)	WotL
Black Fly	Tiny black flies that do not hurt Isaac upon touch.
Attack Fly	Red Flies that follow Isaac and deal touch damage.
Moter	Follows Isaac, similar to Attack Flies. Will split into 2 Attack Flies upon death.	Splits into 4 Attack Flies instead of 2.
Eternal Fly	Invulnerable Fly that circles Corny Poop, Holy Leeches or Hangers.		✔
Pooter	Slow-moving flies that fire single blood shots at Isaac. Pooters do not deal contact damage.	Fires 3 shots in quick succession.
Fat Fly	Alternate version of Pooters. Fires 2 shots in a V-formation and does not deal contact damage.	Fires 3 sets of 3 shots in a V-formation.	✔
Boom Fly	Flies around the room diagonally, dealing touch damage and exploding with a large blast radius upon death.	Explodes with very large blast radius upon death.
Red Boom Fly	Flies around the room diagonally, dealing touch damage and exploding into 6 directional blood shots upon death.	Explodes into a dense ring of blood shots upon death.
Sucker	Flies slowly towards Isaac, exploding into 4 projectiles in a + formation upon death.	Shoots 4 projectiles in a + formation, exploding into 8 blood shots upon death.
Spit	Flies slowly towards Isaac, exploding into an IPECAC shot upon death which targets other Spits in the room, or Isaac.	Shoots 4 projectiles diagonally, exploding into 3 IPECAC shots upon death.	✔
Spider	Moves erratically around the room, damaging Isaac by touch.		✔
Big Spider	Moves erratically around the room, splitting into two Spiders upon death.	Explodes into many Spiders upon death.	✔
Trite	Quickly jumps towards Isaac with high distance. If Isaac is too far away it will jump around randomly.	Leaves slowing creep and shoots 4 projectiles in a + formation wherever it lands.	✔
Boil	Stationary enemy that shrinks upon being hit. Will quickly swell up if not killed in time. Fires multiple short-ranged blood projectiles when fully swollen.	Fires a larger volley of blood projectiles.
Gut	Stationary enemy that shrinks upon being hit. Will quickly swell up if not killed in time. Fires an IPECAC shot when fully swollen.	Fires 3 IPECAC shots instead of one.	✔
Sack	Stationary enemy that shrinks upon being hit. Swells up slower than Guts and Boils. Spawns a Spider when fully swollen.	Spawns two Spiders instead of one.	✔
Walking Boil	Mobile Boil that cannot shrink, but has a finite amount of health. Fires short-ranged blood shots with varying sizes at a reduced fire rate.	Fires a larger volley of blood projectiles.	✔
Walking Gut	Mobile Gut that cannot shrink, but has a finite amount of health. Fires IPECAC shots at a reduced fire rate.	Fires 3 IPECAC shots instead of one.	✔
Walking Sack	Mobile Sack that cannot shrink, but has a finite amount of health. Spawns Spiders.	Spawns two Spiders instead of one.	✔
Mulligan	Harmless enemy that walks around the room, avoiding Isaac. Will spawn multiple flies upon death.	Periodically fires 4 shots in a + formation whenever Isaac is standing to that formation.
Mulligoon	Harmless enemy that walks around the room, avoiding Isaac. Will drop a Troll Bomb upon death.	Periodically spawns Spiders while running away.
Mulliboom	Walks towards Isaac, exploding with a large blast radius upon death or upon touching Isaac. The explosion does a half-heart of damage instead of the regular full heart.	Continuously fires two IPECAC shots while walking.	✔
Hive	Walks around the room, avoiding Isaac while spawning Attack Flies. Spawns a large number of Flies upon death.	Spawns two flies instead of one each time, and spawns more flies upon death. Can sometimes be a mini-boss with health bar and larger body, spitting eternal flies and has orbital eternal flies.
Swarmer	Slowly floats around the room, spawning a Pooter upon taking damage. Spawns a large number of Flies upon death.	Spawns Eternal Flies instead of regular Flies, one Pooter and one Eternal Fly when damaged, and will split into 3 non-Eternal Swarmers when killed.	✔
Hopper	Jumps around the room slowly, damaging Isaac by touch.	Stands still before start pursuing Isaac, firing 4 blood projectiles in a + formation after it lands.
Flaming Hopper	Jumps around the room quickly, covering a large distance, similar to Trites.	Stands still before start pursuing Isaac, firing 4 blood projectiles in a + formation after it lands.
Leaper	Jumps around the room quickly, but not as fast as F. Hoppers. Occasionally jumps high into the air, dropping down elsewhere while firing 4 blood shots in a plus pattern.	Stands still before start pursuing Isaac, firing 4 blood projectiles in a + formation after it lands, and 8 blood shots in all directions after the big jump.
Pacer	Walks aimlessly around the room. Usually spawned after killing a Gaper/Frowning Gaper.
Gusher	Walks aimlessly around the room, firing extremely short-ranged blood projectiles from its head. Usually spawned after killing a Gaper/Frowning Gaper.	Walks towards Isaac, firing fast projectiles in Isaac's general direction.
Gaper	Walks towards Isaac, dealing contact damage. Usually turns into a Pacer or Gusher upon death.	Always turns into an Eternal Gusher or Eternal Horf upon death.
Frowning Gaper	Walks towards Isaac, dealing contact damage. If Isaac is in sight, its eyes will open and it will walk faster. Usually turns into a Pacer or Gusher upon death.	Always turns into an Eternal Gusher or Eternal Horf upon death.
Gurgle	Slowly walks towards Isaac, firing short-ranged IPECAC shots at him. Has much more health than regular Gapers.	Leaves a trail of damaging creep and fires a long-ranged homing IPECAC shot at Isaac.	✔
Mr. Maw	Walks towards Isaac, quickly launching its head, still attached to its body by a cord. Turns into a Maw or Pacer upon death.	Shoots 8 shots in all directions every time it shoots its head.
Horf	Stationary enemy that fires medium ranged blood shots at Isaac.	Shoots a wide spread of 5 blood shots each time.
Maw	Floats towards Isaac, firing fast-moving blood shots.	Fires spread volleys of 9 blood projectiles.
Red Maw	Floats towards Isaac faster than regular Maws, exploding into 4 blood shots in a plus pattern upon death. Does not fire any shots.	Constantly leaves red creep and explodes into 8 shots in all directions upon death.
Psychic Maw	Alternate version of a Maw, has an Eternal Fly circling it. Fires large, purple homing shots at Isaac.	3 Eternal Flies instead of one.	✔
Globin	Walks towards Isaac, dealing one heart of contact damage. Turns into a pile of goo after taking enough damage, where it can be killed. Will regenerate after a short amount of time if not killed quickly.	Fires a ring of 8 blood projectiles after collapsing into a pile of goo.
Gazing Globin	Quickly walks towards Isaac, dealing one heart of contact damage. Turns into a pile of goo and slides away after taking enough damage, where it can be killed. Will regenerate after a short amount of time if not killed quickly.	Fires a ring of 8 blood projectiles after collapsing into a pile of goo, also keeping firing while slide away.
Knight	Moves erratically around the room. Can only be damaged from behind.	Reflects Isaac's shots on its face and leaves red creep each time it takes damage.
Selfless Knight	Moves erratically around the room, charging at Isaac at very high speed. Can only be damaged from behind.	Reflects Isaac's shots on its face and leaves red creep each time it takes damage.
Mask + Heart	Invulnerable mask with a slow-moving Heart. Functions similarly to a Knight. The Heart fires 4 blood shots in a plus pattern when Isaac gets near. Killing the Heart will automatically kill the Mask.	Eternal Heart fires 8 shots in all directions in quick succession, shooting 4 shots in the cardinal directions upon death. Eternal Mask immediately teleport back to the corresponding Heart and start charging should the Heart take damage.	✔
Clotty	Moves around the room, firing 4 blood shots in a + pattern.	Fires 3 sets of 4 blood projectiles in a + pattern as well as multiple various-sized blood projectiles in random directions.
Clot	Moves around the room, firing 4 tar shots in an X pattern.	Fires 3 sets of 4 blood projectiles in an X pattern as well as multiple various-sized blood projectiles in random directions.
I. Blob	Moves around the room, firing 8 shots in all directions.	Fires 3 sets of 8 blood projectiles in all directions as well as multiple various-sized blood projectiles in random directions while also slowly move toward Isaac.	✔
Maggot	Aimlessly moves around the room, damaging Isaac by contact.	Leaves green creep, and after a few seconds, it will transform into an Eternal Sack, which will in turn after a few seconds transform into an Eternal Fat Fly.
Charger	Slowly moves around the room, charging at Isaac when he gets in its line of sight.	Leaves green creep, and after a few seconds, it will transform into an Eternal Sack, which will in turn after a few seconds transform into an Eternal Fat Fly.
Spitty	Slowly moves around the room, firing a single long-ranged blood shot when Isaac gets in its line of sight.	Fires 3 projectiles, one in the center and two in a V-formation when Isaac gets in its line of sight.
Brain	Crawls around the room, leaving a trail of red Creep that does one heart of damage.	Shoots a homing blood shot at Isaac.
MemBrain	Slowly moves around the room, occasionally hopping and firing 8 large blood shots in all directions. Will split into 2 Brains upon death.	Shoots 8 homing blood shots and spawns 3-4 Eternal Brains upon death.
Guts	Attaches itself to a wall or obstacle, such as a Rock, rolling around the room.	Moves faster and occasionally shoots 8 shots in all directions.
Mama Guts	Slowly moves around the room, occasionally hopping and firing 8 large blood shots in all directions. Will split into 2 Guts upon death.	Fires 8 large blood shots in quick succession and spawns 2 Eternal Guts and 1 Eternal Clotty upon death.	✔
B. Licker	Attaches itself to other B. Lickers, erratically moving around the room, similar to Larry Jr.	Starts pursuing Isaac, leaving behind red creep.	✔
Para-Bite	Moves towards Isaac. Can burrow underground and reappear elsewhere.	Stops pursuing Isaac, spawning 3 smaller Eternal Para-Bites that is close to him.
Fred	Fires an IPECAC shot at Isaac. Will hop out of the ground and burrow elsewhere, firing 4 blood shots in an X pattern while doing so.	Fires a homing IPECAC shot at Isaac, leaving 8 shots in all directions when diving into ground.
Lump	Fires 3 fast-moving blood shots at Isaac when he gets in its line of sight. Will burrow underground and reappear elsewhere after firing its shots.	Fires 3 blood shots in quick succession.
Leech	Quickly charges towards Isaac when he gets in its line of sight.
Kamikaze Leech	Quickly charges towards Isaac when he gets in its line of sight. Explodes with a large blast radius upon death.	Shoots continuous shots to both sides while moving and has an Eternal Fly circling it.
Holy Leech	Quickly charges towards Isaac when he gets in its line of sight. Explodes with a large blast radius upon death. Has an Eternal Fly circling it.	Shoots continuous shots to both sides while moving.	✔
Host	Invulnerable stationary enemy. Raises its head up when Isaac gets close, revealing a fleshy stem that can be damaged. Upon raising its head, it will fire 3 blood shots and lower its head again.	Invulnerable stationary enemy that reflects Isaac's tears. Raises its head up when Isaac gets close, revealing a fleshy stem that can be damaged. Upon raising its head, it will either fire 5 blood shots in a V formation and lower its head again, or quickly lower its head and fire 8 shots around it.
Red Host	Stationary enemy that can be damaged even when its head is lowered. Fires 5 blood shots instead of 3 when rising, and fires more frequently.	Fires 7 blood shots in quick succession. Sometimes, it quickly lower its head and fire 8 shots around it.
Vis	Charges up a Brimstone laser when Isaac gets in its line of sight.
Double Vis	Charges up a Brimstone laser which fires from both sides when Isaac gets in its line of sight.	Leaves red creep each time it fires a Brimstone laser.	✔
Chubber	Fires a Little Chubby-like familiar that deals one heart of damage when Isaac gets in its line of sight.	Leaves red creep each time it shoots a Charger.	✔
Poky	Moves around the room, damaging Isaac by contact.
Slide	Quickly slides towards Isaac when he gets in front of it.		✔
Eye	Quickly fires a Technology-like laser at Isaac.	Occasionally shoot continuous blood shots. When this happens, it will keep spinning until it stops after a few seconds.
Bloodshot Eye	Quickly fires a Brimstone-like laser at Isaac.
Dople	Copies Isaac's movements, and fires tears at the same time as him.
Evil Twin	Copies Isaac's movements, and fires tears at the same time as him.
Embryo	Aimlessly hops around the room, damaging Isaac by contact damage.	Shoots large rings of blood shots every time it jumps. Upon taking enough damage, it splits into 4 smaller Eternal Embryos that shoot less blood shots. Smaller Eternal Embryos, however, can only split into 2 even smaller ones, and they no longer shoot blood shots if they are smaller than half-sized ones.
Baby	Fires a single blood shot at Isaac. Can teleport and reappear elsewhere.	Leaves 4 blood shots in a + pattern when teleporting.
Angelic Baby	Fires 3 blood shots at once at Isaac, has much more health than regular Babies.	Leaves 8 blood shots in all directions when teleporting.	✔
Keeper	Hops around the room, firing 2 blood shots in a V formation at Isaac.	Stands still before start pursuing Isaac, firing 4 shots each time it lands and also fires 2 shots in quick succession at Isaac.	✔
Hanger	Floats around the room, firing 3 blood shots at Isaac. Has an Eternal Fly circling it.	Fires 3 homing blood shots at Isaac.	✔
Stone Grimace	Stationary and invulnerable monster that fires a fast-moving blood shot at Isaac. Stops firing when room is cleared.
Vomit Grimace	Stationary and invulnerable monster that fires an IPECAC shot at Isaac. Stops firing when room is cleared.		✔

Monster List by Floor[]

The Basement
Pooter Fly Gaper Horf Gusher Hopper Mulligan Mulligoon Clotty (uncommon) Clot I. Blob (very rare) Spider Moter Sucker Embryo

Cellar
I. Blob (very rare) Clot Sack Gaper Mulligan Mulliboom Spider Big Spider Trite

The Caves
I. Blob (very rare) Boom Fly Maggot Charger Clot Clotty Fly Gusher Hopper Host Hive Maw Moter Spider Trite Spitty Sucker Embryo Knight Selfless Knight (rare) Leaper (rare) Mr. Maw (uncommon)

The Catacombs
Keeper I. Blob (very rare) Buttlicker Embryo Mulliboom Psychic Maw Spider Fat Fly Trite Gurgle Splasher Walking Boil Walking Gut Walking Sack

The Depths
Baby Boil Boom Fly Brain Globin Guts Hive Host Knight Selfless Knight (rare) Leaper Leech Embryo Kamikaze Leech (rare) Mr. Maw Moter MemBrain (very rare) Pooter Psychic Maw (rare) Spider Vis
Degraded Bosses up to the Caves

Necropolis
Angelic Baby (uncommon) Keeper Mama Guts I. Blob (very rare) Boom Fly Buttlicker Hanger Mask + Heart Mulliboom (rare) Spider Slide Swarmer Embryo Vis Double Vis Gurgle Walking Boil Walking Gut Walking Sack
Degraded Bosses up to the Caves

The Womb
I. Blob (very rare) Brain Dople Eye Fly Fred Lech free Holy Leech (uncommon) Host Lump Embryo (uncommon) MemBrain Para-Bite Poky Globin (uncommon) Guts Mr. Maw (uncommon) Spider (uncommon) Vis
Degraded Bosses up to the Caves
A pair of complete Blastocysts or 4 'second stage' Blastocysts may spawn.

Utero
Angelic Baby (uncommon) Mama Guts Buttlicker Dople Fred Guts Gurdy Jr. Mask + Heart Heart Para-Bite Spider (uncommon)
Degraded Bosses up to the Caves
A pair of complete Blastocysts or 4 'second stage' Blastocysts may spawn.

Sheol
I. Blob (very rare) Leech (uncommon) Kamikaze Leech Holy Leech (uncommon) Headless Horseman's Head (2-3) Selfless Knight Dople Evil Twin Sucker Spit Globin (rare) Spider
Degraded Bosses up to the Depths except for Gurdy
Two Greeds and a whole Fistula.
Rarely monsters from early levels, such as a non-aggressive fly will spawn in rooms by themselves. This might be a bug.

Cathedral
Angelic Baby I. Blob Clot Holy Leech Spit Spider
Degraded Bosses up to the Womb

The Chest
Spider Slide
Degraded Bosses up to the Womb

Monster replacements[]

Some monsters in the Binding of Isaac are randomly replaced by similar counterparts. These can either be "champion" versions that are recolored or completely different enemies with modified attacks.

Champion Enemies[]

Main article: Champion

Normal enemies can be recolored to become champion enemies, which by default have twice as much HP as their normal counterparts. Similarly, some champion enemies are able to deal full heart damage regardless of the level. Champion enemies will always drop a free pickup when killed.

Enemy Variants[]

These variants may replace normal enemies in a room.

Some variants will additionally count as champion enemies if encountered on certain floors. For example, Bloodshot Eyes, Selfless Knights, Kamikaze/Holy Leeches and the Evil Twin can be considered champions when encountered in the Womb or earlier and will drop a pickup when killed.

Replacement/Variation Chart
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