Vanishing Twin is an unlockable familiar in The Binding of Isaac, added in the Repentance DLC.

Spawns a fetus familiar that follows Isaac.

After entering a Boss Room, the familiar will move to the center of the room, and transform into a clone of the boss. Isaac must defeat both bosses in order to proceed.

When this happens, both the original boss and its copy will be set to 75% of their maximum health, and will gain slightly reduced movement and attack speed.

Upon dying, the clone will drop an item from the Boss item pool, even before the fight is over. The original boss will also grant another item.

The cloning can happen only once per floor.

The familiar cannot clone mini-bosses and final bosses such as Mom, Mom's Heart, Isaac, Satan, etc.

The familiar can clone the boss even after it's been defeated.

On floors with multiple boss rooms, the familiar will act only on the first boss encountered.

If it clones Great Gideon, 2 extra waves of enemies are added to the battle.

The item is removed from item pools and cannot be found normally starting from Chapter 4.

The item has no effect in Greed Mode.

This page shows the latest information as of the new Repentance+ (Online Co-op) DLC.
To see information about this item for the previous Repentance version, check this page instead.

Defeat Hush as Jacob and Esau.

Vanishing Twin can be found in the following item pools:

The following tags are applied to this item:

Below is the Internal Item Description as shown in-game.
Note that some stat changes are not displayed here. Please see the main description for the full effects.

Vanishing Twin

• Grants a fetus familiar that transforms into a slightly weaker copy of the boss upon entering the floor's boss room
• Both the boss and the copy must be defeated and they will each drop an item
• Abyss: x1 locust .75x Isaac's damage

• Check out the item description on the external Isaac Wiki.