Transformations

Transformations

Guppy	Beelzebub	Super Bum	Yes Mother	Bob	Fun Guy	Leviathan	Conjoined
Spun	Seraphim	Oh Crap	Bookworm	Spider Baby	Adult	Stompy

Transformations alter Isaac's appearance and grant him special abilities.

A transformation occurs when obtaining at least three collectibles from a particular set of items.
These collectibles always share a particular theme that corresponds with the transformation.

Transformation sets

The Binding of Isaac: Rebirth

Transformation	Appearance	Transformation effect	Item	Icon	Item effect	Recharge
Beelzebub		Flight. Converts small enemy flies into blue flies.
			???'s Only Friend		Summons a big attack fly that can be controlled with the shooting direction-keys.
			Angry Fly		Spawns a fly familiar that orbits around a random enemy and deals 2 damage per tick to enemies it comes in contact with.
			BBF		Spawns a familiar that flies around the room in a manner similar to the Boom Fly and explodes on contact with an enemy. Respawns after ten seconds.
			Best Bud		When hit, summons a white attack fly similar to Distant Admiration for the current room.
			Big Fan		Spawns a large orbital familiar that blocks enemy projectiles and deals slight contact damage to enemies.
			Distant Admiration		A red attack fly circles further out than the Halo of Flies / Pretty Flies, but closer than Forever Alone. Deals more damage than Forever Alone.
			Forever Alone		Spawns a blue attack fly that orbits a long distance from Isaac.
			Halo of Flies		Spawns two pretty fly familiars that block enemy shots and deal contact damage to enemies.
			Hive Mind		Increases the size of blue spiders and Blue Flies and doubles the amount of damage they deal.
			Skatole		All types of fly except Boom Fly and Red Boom Fly become passive and slowly move towards Isaac. Does not prevent contact damage.
			Smart Fly		After Isaac takes damage, this fly will deal continuous touch damage to whatever enemy caused the damage until it is dead. The fly will then systematically attack 1 enemy at a time until the room is cleared.
			The Mulligan		Tears have a 1/6 chance of spawning allied blue flies when they hit an enemy.
			Infestation		1-3 Blue flies randomly spawn every time Isaac gets hit.
			Friend Zone		A white orbiting fly which deals 3 contact damage per tick to enemies. This familiar orbits Isaac at a middle length distance somewhere between Distant Admiration and Forever Alone.
			Lost Fly		A familiar fly that moves in a straight line and attaches itself to the first obstacle or wall it comes into contact with in each room. If any enemies walk into its path, it will deal 7 contact damage per tick. If the obstacle it is attached to is destroyed then it will continue rolling in the direction it was previously travelling until it meets another wall or obstacle.
			Papa Fly		A blue fly familiar follows Isaac's movements on a 3 second delay. Papa Fly will fire tears at nearby enemies.
			Obsessed Fan		A purple fly familiar that follows Isaac's movements on a 3 second delay and deals contact damage to enemies.
Guppy!		Flight. Spawns a Blue Fly each time a tear hits an enemy.
			Guppy's Head		Spawns 2-4 blue flies to damage enemies.	1
			Guppy's Paw		Removes one red heart container in exchange for gaining 3 Soul Hearts.	0
			Dead Cat		Sets the amount of red heart containers to 1, but gives Isaac 9 extra lives. After dying, Isaac is teleported to the last safe room. New heart containers can be obtained after picking up this item, but after each death, the number of heart containers is set to 1 again.
			Guppy's Collar		Grants Isaac a permanent 50% chance to respawn with 1/2 of a red heart after death.
			Guppy's Tail		Increases chance of finding gold chests and normal chests, but reduces chance of finding pickups.
			Guppy's Hair Ball		Loosely follows behind Isaac. Can be swung like a flail by rapidly spinning Isaac in a circle. Grows bigger by killing enemies.

The Binding of Isaac: Afterbirth

Transformation	Appearance	Transformation effect	Item	Icon	Item effect	Recharge
Bob		Isaac gains a green trail of poisonous creep.
			Bob's Rotten Head		Upon use, Isaac holds a poison bomb which can be thrown towards any of the four cardinal points and explodes on impact.	3
			Bob's Brain		Spawns a familiar that charges forward when shooting tears, explodes upon contact with an enemy and poisons them. Respawns after few seconds.
			Bob's Curse		Gives 5 bombs and grants all bombs poison effect.
			Ipecac		Replaces tears with explosive and poisoning projectiles fired in an arc from the mouth.
Conjoined		When attacking, the tumor faces shoot tears diagonally outwards, similar to the effect of The Wiz. -0.3 damage. Slightly decreases tears.
			Brother Bobby		Follows Isaac around shooting normal tears.
			Harlequin Baby		Spawns a familiar that follows Isaac around and fires two tears at once in a V-pattern.
			Headless Baby		Familiar that follows Isaac, leaving blood creep on the ground.
			Little Steven		Spawns a familiar that follows Isaac around and fires homing tears.
			Mongo Baby		Summons a familiar that copies the tears of Isaac's other familiars.
			Rotten Baby		A familiar that spawns blue flies.
			Sister Maggy		A familiar that follows Isaac around shooting blood tears.
Fun Guy		+1 heart container.
			God's Flesh		Tears now have a random chance to apply a shrinking effect, causing enemies to shrink in size and also run away from Isaac. Shrunk enemies can be crushed and killed by walking over them.
			Mini Mush		Increases Speed and Shot Height and decreases Isaac's size, but lowers Range.
			Magic Mushroom		Increases all stats and enlargens Isaac.
			Odd Mushroom		Increases Tears and Speed while reducing Damage.
			Odd Mushroom		Grants an empty heart container. Increases damage, range and shot height while reducing speed.
			1up!		Gives an extra life. Upon death, you will respawn in the previous room with full health and lose the 1up!.
			Blue Cap		Grants 1 heart container and increases tears, but decreases shot speed.
Leviathan		Flight. +2 black hearts.
			The Nail		Adds one soul heart and allows the breaking of rocks and damaging enemies by simply walking over them. Increases damage and decreases speed. All effects except for the Soul Heart wear off upon leaving the room.	6
			The Mark		Increases Damage and Speed, plus adds one Soul Heart.
			Missing Page 2		Gives 1 black heart. Upon taking damage that reduces Isaac's health to one heart or less, activates The Necronomicon effect, dealing 40 damage to all enemies in the room.
			The Pact		Increases damage by 0.5, tears by 0.7 and grants two soul hearts upon pickup.
			Pentagram		Increases damage and increases the chance for a Devil or Angel Room to appear.
			Spirit of the Night		Grants spectral tears and flight.
			Maw of the Void		+1.0 Damage Up. After continuously firing tears for 2.5 seconds, a red cross appears on Isaac's head that, upon releasing the fire button, creates a black ring that rapidly deals damage equal to Isaac's tear damage to any enemies in contact with it.
			Abaddon		Increases damage and speed, removes all red heart containers, grants six black hearts, and adds a chance to shoot fear tears.
			Brimstone		Tears are replaced by a laser beam that pierces through all enemies and obstacles in its path and deals high damage. Can only be fired after a short charge-up period.
Oh Crap		Whenever a pile of poop is destroyed, health is replenished by half a heart.
			Flush!		Changes all enemies in the room into poop. Does not work on all enemies (Knights and bosses are immune). Instantly kills Dingle, Dangle, and Brownie.	6
			The Poop		Spawns a pile of poop where the character is standing and knocks nearby monsters back. May yield pickups like regular poop.	1
			E Coli		Gives "Turdy Touch" Effect. Enemies that touch Isaac are changed into poop.
Seraphim		Flight. +3 soul hearts.
			The Bible		Upon activation, Isaac gains flight, allowing him to pass over all obstacles in the current room. Instantly kills Mom, Mom's Heart, and It Lives when activated, but will kill Isaac when activated while fighting Satan.	6
			Dead Dove		Grants spectral tears and flight.
			Guardian Angel		Spawns an orbital familiar that blocks enemy projectiles, deals contact damage to enemies, and increases the speed of all orbital familiars.
			Holy Grail		Grants flight and one heart container.
			Holy Mantle		Automatically negates first taken damage in every room.
			Mitre		Grants a chance of converting any red hearts pickups into soul hearts instead.
			Rosary		Adds 3 Soul Hearts and increases the chance for The Bible to appear in any item pool.
			Sworn Protector		An orbital angel which does 7 contact damage per tick and blocks enemy shots. When it blocks a shot, it has a very small chance to drop an eternal heart.
			The Halo		Grants one Heart Container, +0.3 Damage, +0.2 Tears, +0.25 Range, +0.3 Speed, and +0.5 Tear Height.
Spun		+2 damage. +0.15 speed. Spawns a random pill upon transformation.
			Adrenaline		Increases damage based on how many empty heart containers Isaac has.
			Euthanasia		Adds a chance to fire needles. If a needle kills an enemy, it bursts into more needles.
			Experimental Treatment		Randomly increases and decreases some of the character's stats. There will always be at least one stat increase and one decrease and the same stats can be increased/decreased multiple times.
			Growth Hormones		Increases damage by 1 and speed by 0.4.
			Roid Rage		Increases speed by 0.6, range by 5.25, and tear height by 0.5.
			Speed Ball		Increases speed by 0.3 and shot speed by 20%.
			Synthoil		Increases damage by 1, range by 5.25, and tear height by 0.5.
			The Virus		Inflicts poison to enemies who make contact with Isaac. Speed down.
Yes, Mother?		Isaac gains a stationary knife that trails directly behind him. It synergizes like Mom's Knife would.
			Mom's Bottle of Pills		Gives Isaac a random pill, and will cause him to drop any held Q-slot item (If any). The player will only receive six different pill types in one playthrough.	6
			Mom's Bra		Upon use, petrifies all enemies in the current room for approximately 4 seconds.	3
			Mom's Pad		Upon use, inflicts fear to all enemies in the room for 5 seconds.	3
			Mom's Wig		Adds a chance to spawn blue spiders when firing tears. Restores 1 red heart.
			Mom's Eye		Allows Isaac to fire tears from the back of his head.
			Mom's Purse		Allows Isaac to hold 1 additional trinket.
			Mom's Contacts		Adds a chance to shoot petrifying tears, which stop enemies in place and prevent them from moving or attacking. Range up.
			Mom's Knife		Isaac's tears are replaced by a knife that pierces enemies, can travel through obstacles, and can hurt enemies while Isaac is holding it. Holding down the fire button before firing increases its range and power.
			Mom's Heels		Increases range.
			Mom's Eyeshadow		Tears have a chance to charm enemies.
			Mom's Perfume		Adds a chance to shoot fear tears and decreases tear delay by 1.
			Mom's Key		Spawns 2 keys. Generates additional pickups from chests.
			Mom's Lipstick		Increases range and shot height.
			Mom's Underwear		Increases range.
			Mom's Coin Purse		Spawns 4 random pills around Isaac.
			Mom's Pearls		+1.25 Range Up. +0.5 Tear Height. +1 Luck Up.
			Mom's Razor		Spawns an orbiting razor that damages enemies it touches and inflicts bleeding on enemies, causing them to slowly take damage over time.
Super Bum	1	Replaces Bum Friend, Dark Bum, and Key Bum for Super Bum. He collects any of the other beggars' pickups, and offers twice the rewards.
			Bum Friend		A portable beggar who follows Isaac, picks up coins for himself, and occasionally drops a pickup after collecting a coin. Does not spawn collectibles.
			Dark Bum		Spawns a familiar that follows Isaac around and collects red hearts. For every one-and-a-half red hearts collected, Dark Bum will generate one soul heart, one hostile Spider or one friendly blue spider.
			Key Bum		Spawns a portable key master that follows Isaac and collects keys, giving random chests in return.

^{1: Image depicts the familiar. This transformation does not alter Isaac's appearance.}

The Binding of Isaac: Afterbirth†

Transformation	Appearance	Transformation effect	Item	Icon	Item effect	Recharge
Bookworm		Roughly 50% of the time, Isaac shoots an extra tear, like 20/20.
			Anarchist Cookbook		Spawns six troll bombs around the room.	3
			Book of Revelations		Adds 1 soul heart, increases the chance for a Devil or Angel Room to appear, and increases the chance for the next boss to be a Horseman (except on XL floors and floors with fixed bosses such as Mom).	6
			Book of Secrets		Upon use, gives the effect of Treasure Map, The Compass, or Blue Map for the duration of the current floor.	6
			Book of Shadows		Upon use, creates a protective shield nullifying all types of damage for 10 seconds.	3
			How to Jump		Gives Isaac the ability to jump (over gaps, spikes, etc.).	0
			Monster Manual		Summons a random familiar for the current room. Can summon familiars not yet unlocked.	3
			Satanic Bible		Upon activation, Isaac gains a black heart.	6
			Telepathy for Dummies		Upon activation, grants homing tears for the current room.	2
			The Bible		Upon activation, Isaac gains flight, allowing him to pass over all obstacles in the current room. Instantly kills Mom, Mom's Heart, and It Lives when activated, but will kill Isaac when activated while fighting Satan.	6
			The Book of Belial		Upon use increases damage by 2 for the current room and by a further +50% if the character also has the Blood of the Martyr. Guarantees a Devil Room or Angel Room will be open after beating a boss while holding it. Increases the chance for a Devil or Angel Room to appear by 12.5%.	3
			The Book of Sin		Spawns a random pickup, pill, card, or trinket.	4
			The Necronomicon		Damages all enemies in the room significantly.	6
Spider Baby		Spawns a spider familiar that applies random status effects to enemies it comes in contact with.
			Box of Spiders		Summons 2-4 blue spiders.	2
			Mutant Spider		Grants quadruple shot but decreases tears.
			Spider Baby		When hit, spawns up to 2 blue spiders.
			Spider Bite		Adds a chance to shoot slowing tears, reducing speed of enemy movement and any projectile fired by them.
			Spider Butt		Damages all enemies in the room and slows them and their projectiles down.	2
			Spider Mod		Displays Isaac's tear damage and enemy health bars. Spawns a gray spider familiar that wanders around and inflicts a random status effect on any enemies it comes into contact with. Occasionally spawns a blue spider upon clearing a room.
Adult		Grants a heart container.
			3 Puberty pills
Stompy	None	Taking damage has a chance to spawn rock waves.
			Leo		Allows you to crush rocks when you walk over them.
			Magic Mushroom		Increases all stats and enlargens Isaac.
			One Makes You Larger pills

Notes

• Activated items (e.g. Guppy's Head ) only need to be touched in order to count. Keeping them, or even activating them once, is not required.
• Rerolling items with a dice room, the D4 , or the D100 will not remove progress towards the transformation.
• Transformations can be combined with each other, keeping the effects of any and all transformations with no effects overriding others.
• Transforming into Beelzebub for the first time will unlock the Lord of the Flies achievement.
• Since none of the Afterbirth transformations unlock an achievement or item, attaining them is not required for 100% completion of the game in terms of achievements.
• Many of the Afterbirth transformations override the charge animations of items such as Monstro's Lung and Brimstone , potentially making them more difficult to use.
  • There is now an option to show a charge bar that floats above Isaac.
• Familiars gained from Cambion Conception or Immaculate Conception do not count towards transformation progress.

Trivia

• There are two transformations in the base game, nine more in the Afterbirth DLC, and four more in the Afterbirth † DLC.
• In the original The Binding of Isaac flash game, the transformation into Guppy was the only one available, making it chronologically the first.
  • The Eternal Edition of the original The Binding of Isaac game added another transformation that turned Isaac into an angel after gaining 7 heart containers from eternal hearts.
• Rebirth introduced Beelzebub as the chronologically second transformation.
• The original name for the Beelzebub transformation was Lord of the Flies.