Burning Basement

The Burning Basement is one of the environments in Chapter 1 added in the Binding of Isaac: Afterbirth expansion. The theme of the Burning Basement is fire, and most enemies are replaced with burning versions. There are relatively few flying or shooting enemies; most of the enemies are ground-based and rely on contact damage. Rocks have a chance to be replaced with fireplaces.

The Burning Basement's alternate floors are The Basement and The Cellar.

The Burning Basement is unlocked by defeating Mom's Heart 11 times.

Monsters

Monsters	Description
Black Fly	Tiny black fly with neutral AI. Does not hurt Isaac upon touch.
Attack Fly	Red fly that follows Isaac and deals touch damage.
Ring Fly	Gathers with any other Ring Flies in the room. These flies orbit around themselves, while following Isaac.
Dart Fly	Flies towards Isaac and attempts to mimic his movements. Deals contact damage.
Swarm Fly	Follows Isaac in large groups and deals contact damage.
Moter	Follows Isaac, similar to Attack Flies. Splits into 2 Attack Flies upon death.
Eternal Fly	Invulnerable fly that circles corny poop and various monsters. Turns into a vulnerable Attack Fly after the object or monster it circles is destroyed.
Pooter	Slow-moving fly that occasionally fires single blood shots at Isaac. Does not deal touch damage.
Level 2 Fly	Flies toward Isaac erratically, dealing touch damage.
Full Fly	Flies toward Isaac erratically, dealing touch damage. Splits into 6 directional shots upon death.
Sucker	Flies slowly towards Isaac, exploding into 4 shots in the cardinal directions upon death.
Spit	Flies slowly towards Isaac, firing an Ipecac shot towards Isaac upon death.
Dip	Slowly dashes in random directions, dealing contact damage.
Squirt	Dashes towards the player and deals contact damage. Spawns 2 Dips upon death.
Spider	Erratically moves towards Isaac and deals touch damage.
Big Spider	Erratically moves towards Isaac and deals touch damage. Splits into two Spiders upon death.
Trite	Quickly leaps towards Isaac and deals touch damage.
Level 2 Spider	Crawls around the room erratically, following Isaac and dealing touch damage. Can jump small distances.
Ticking Spider	Crawls around the room erratically, following Isaac and dealing touch damage. Can jump small distances. Explodes upon death.
Baby Long Legs	Runs away from Isaac and frequently spawns Spiders.
Small Baby Long Legs	Runs away from Isaac and occasionally spawns Sacks.
Crazy Long Legs	Chases Isaac, dealing touch damage. Occasionally stops to spit blood shots in 8 directions.
Small Crazy Long Legs	Chases Isaac, dealing touch damage. Occasionally stops to spit blood shots diagonally in 4 directions.
Wall Creep	Crawls along walls to try to line up with Isaac and shoots three blood shots in a line.
Sack	Stationary enemy that decreases in size when hit, but regenerates to its full size until fully destroyed. Occasionally spawns Spiders when fully swollen.
Walking Sack	Does not shrink or regenerate. Walks around aimlessly and occasionally spawns Spiders.
Round Worm	Pops out of the ground in random locations and spits a blood shot at Isaac if he is in sight.
Roundy	Pops out of the ground in random locations, creating a small rock wave. Fires an explosive Ipecac shot at Isaac if he is in sight.
Ulcer	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.
Mulligan	Walks around the room, avoiding Isaac. Upon death, spawns several flies, which can be Black Flies, Attack Flies, or Pooters. Can suicide to explode and launch projectiles in the four ordinal directions while still releasing flies.
Mulligoon	Walks around the room, avoiding Isaac. Upon death, spawns a Troll Bomb and fires four shots in the ordinal directions. Can suicide to explode, spawn a Troll bomb, and launch projectiles in eight directions.
Mulliboom	Chases Isaac and explodes upon death or upon touching Isaac. The explosion deals a half-heart of damage instead of the regular full heart.
Nest	Walks around the room, avoiding Isaac while spawning Spiders. Spawns a Big Spider or a Trite upon death.
Dukie	Flies around the room diagonally, occasionally spitting out a Dart Fly.
Hopper	Slowly hops around the room, dealing touch damage. Can turn into a Flaming Hopper by jumping into fire.
Flaming Hopper	Quickly hops around the room, dealing touch damage. Covers a larger distance than the regular Hopper.
Pacer	Walks aimlessly around the room.
Gusher	Walks aimlessly around the room, occasionally firing short-ranged blood shots.
Gaper	Walks towards Isaac, dealing contact damage. Usually turns into a Pacer or a Gusher upon death.
Frowning Gaper	Walks towards Isaac, dealing contact damage. Upon getting near Isaac, it will open its eyes and pursue Isaac faster. Usually turns into a Pacer or a Gusher upon death.
Flaming Gaper	Walks towards Isaac, dealing contact damage. Usually turns into a Pacer or a Gusher upon death.
Cyclopia	Walks towards Isaac, dealing contact damage and leaving behind a trail of damaging red creep. Occasionally shoots a blood shot towards Isaac.
Skinny	Slowly walks towards Isaac, leaving short-lasting red creep behind itself.
Crispy	Slowly walks towards Isaac, but increases in speed as they take damage. Constantly passively takes damage.
Horf	Stationary enemy that fires a medium ranged blood shot at Isaac when he gets in range of them.
Fatty	Slowly walks towards Isaac. Occasionally farts, which pushes Isaac and adjacent enemies away.
Flaming Fatty	Slowly walks towards Isaac. Occasionally farts, which pushes Isaac and adjacent enemies away. Has a chance to leave behind a damaging flame upon death.
Clotty	Randomly wanders around the room, firing 4 blood shots in the cardinal directions.
Clot	Randomly wanders around the room, firing 4 tar shots in the ordinal directions.
I.Blob	Randomly wanders around the room, firing 8 shots in all directions.
Wall Hugger	Moves around the room like Guts, damaging Isaac by contact. Cannot be destroyed.
Embryo	Aimlessly hops around the room, dealing contact damage.

Bosses

Monstro Larry Jr. The Duke of Flies Famine The Haunt

Rag Man Little Horn

Unlockable Achievements

• 

  Monstro's Tooth - Beat chapter 1 for the 1st time.

• 

  Something From The Future - Beat The Basement 40 times.

• 

  Sprinkler - Beat chapter 1 without taking damage.

• 

  Basement Boy - Beat chapter 1 without taking damage.

Music

The track that plays in the Burning Basement is titled Fundamentum.