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 different items from a particular set of items.
These collectibles always share a particular theme that corresponds with the transformation.

Transformation sets

Name	Appearance	Description	Items
Beelzebub		Flight. Converts small enemy flies into blue flies.
Guppy		Flight. Spawns a blue fly each time a tear hits an enemy.
Bob		Isaac gains a green trail of poisonous creep.
Conjoined		When attacking, the tumor faces shoot tears diagonally outwards, similar to the effect of The WizTears simultaneously fire out of both eyes diagonally, similar to the effect of the R U A Wizard? pill. Isaac's tears also travel above all obstacles.. -0.3 damage. Slightly decreases tears.
Fun Guy		+1 heart container.
Leviathan		Flight. +2 black hearts.
Oh Crap		Whenever a pile of poop is destroyed, health is replenished by half a heart.
Seraphim		Flight. +3 soul hearts.
Spun		+2 damage. +0.15 speed. Spawns a random pill upon transformation.
Super Bum		Replaces Bum FriendA portable beggar who follows Isaac, picks up coins for himself, and occasionally drops a pickup after collecting a coin. Does not spawn collectibles., Dark BumSpawns 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., and Key BumSpawns a portable key master that follows Isaac and collects keys, giving random chests in return. for Super Bum. Collects any of the other beggars' pickups, and offers twice the rewards.
Yes Mother?		Isaac gains a stationary knife that trails directly behind him. It synergizes like Mom's KnifeIsaac'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. would.
Adult		Grants a heart container.
Bookworm		Roughly 50% of the time, Isaac shoots an extra tear, like 20/20Grants double shot..
Spider Baby		Spawns a spider familiar that applies random status effects to enemies it comes in contact with.
Stompy	None	Taking damage has a chance to spawn rock waves.

Requirements

• Items only need to have been acquired once in order to count. Keeping them is not required.
  • Duplicate items (like those acquired from DiplopiaDuplicates all pickups and item pedestals in the room.) do not count toward transformations when picked up. Only the first instance of an item Isaac owns will count.
  • Activated collectibles (e.g. Guppy's HeadSpawns 2-4 blue flies to damage enemies.) can be picked up once and then swapped away with another without any loss to transformation progress.
  • Rerolling items with a dice room, the D4Rerolls all of Isaac's items., or the D100Upon use, rerolls all passive items on Isaac like the D4, every pedestal item in the room like The D6, and every pickup like the D20. will not remove progress towards the transformation.
  • Familiars gained from Cambion ConceptionAfter taking damage a certain amount of times, a permanent demonic familiar spawns. or Immaculate ConceptionUpon picking up a certain amount of health, spawn a permanent angelic familiar. do not count towards transformation progress.
• Trinkets do not count toward progress for any transformation.
• Pills only count toward Adult and Stompy, they do not count toward progress for any other transformation.

Notes

• 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 and Angry FlySpawns a fly familiar that orbits around a random enemy and deals 5 damage per tick to enemies it comes in contact with..
• 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. However, this is only true if you unlocked Mom's ContactsAdds a chance to shoot petrifying tears, which stop enemies in place and prevent them from moving or attacking. Range up. on Rebirth, as the Yes Mother? transformation will happen once you collect three Mom items on Afterbirth and Afterbirth † .
• Many of the Afterbirth transformations override the charge animations of items such as Monstro's LungIncreases damage and grants a charged shot that fires multiple tears in the same fashion as Monstro. and BrimstoneTears 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., potentially making them more difficult to use.
  • There is now an option to show a charge bar that floats above Isaac.

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.