- Adds a 50% chance to duplicate one of Isaac's familiars when entering a new room.
- If Isaac has no familiars, spawns Brother Bobby or Sister Maggy instead.
- The following items/trinkets cannot be duplicated:
- Halo of Flies/Pretty Flies
- Wisps given by Book of Virtues, Jar of Wisps, Beth's Essence, Beth's Faith, Lemegeton, or Vengeful Spirit
- Abyss/ Apollyon's Best Friend’s unique attack locusts
- Temporary familiars generated by Monster Manual
- Dead Bird
- Dead Cat
- Isaac's Heart
- Giant Cell
- Spin to Win
- The Swarm
- The Intruder
- Vanishing Twin
- ???'s Soul
- Isaac's Head
- Umbilical Cord
- Mom's Box: Has an additional 50% chance to trigger the effect again, resulting in another familiar doubling. This can be the same familiar that was doubled originally.
- Movement-mimicking familiars: Duplicated familiars will follow the original on the same delay.
- In the case of Shade, a copy of the familiar will spawn even if Shade was already absorbed by Isaac.
- Pickup-generating familiars: If they remain duplicated for enough consecutive rooms, they will give a pickup as normal. The following familiars have to be duplicated for the following number of consecutive room clears to give pickups:
- Sack of Pennies: 1 room (will give a coin every time it’s duplicated)
- Bomb Bag/ Little C.H.A.D.: 2 rooms
- Mystery Sack/ Rune Bag/ Sack of Sacks: 5 rooms
- Acid Baby: 6 rooms
- The Relic: 7 rooms
- Cambion Conception/ Immaculate Conception: Familiars given by these items can be duplicated as normal.
- Bum Friend/ Dark Bum/ Key Bum/ Bumbo/ Lil Portal: The pickup count of duplicated familiars is not remembered when they go away.
- Ball of Bandages/ Cube of Meat: Upgrades the familiar instead of duplicating it.
- Best Bud/ Bird Cage: If the trinket tries to duplicate it, it will instead immediately activate. Taking damage does not spawn another familiar.
- If this happens to Bird Cage as Isaac walks into a room with enemies, Bird Cage will also leap onto the enemies.
- Blood Puppy/ Bumbo/ Guppy's Hair Ball: The duplicate will always be at its first stage.
- 1up!: Despite the fact that it can be duplicated, Isaac will not keep the 1up if he dies while it's duplicated.
- Guillotine: The head can be duplicated, and will give an extra damage and tears up if it is. The extra head will be unable to fire tears.
- GB Bug: The familiar can be duplicated even if it hasn’t respawned; by constantly moving to new rooms, GB Bug can constantly respawn, allowing pickups to be rerolled indefinitely.
- Succubus: The damage multiplier from standing in the aura of multiple Succubi multiplicatively stacks.
- Buddy in a Box: The duplicated familiar will be randomly generated instead of copying the original.
- Hallowed Ground: Duplicate poops will also drop when Isaac takes damage. The bonuses from standing in the aura of multiple white poops does not stack.
- YO LISTEN!: An extra +1 luck will be given for every duplicate.
- Mystery Egg: The friendly the duplicated egg spawns depends on how many consecutive rooms cleared the duplicate persisted for.
- Lost Soul/ Star of Bethlehem: The trinket can try to make a duplicate of the familiar, but it will always fail. This reduces the odds of the trinket giving copies of other familiars or prevents it from giving Brother Bobby or Sister Maggy if he has no other familiars.
- Soul of Lilith: Familiars given can be duplicated as normal.
- Strawman: Keeper cannot be duplicated, as he is considered a character, not a familiar.
|The Binding of Isaac: Rebirth|
|Achievements||Attributes||Bosses||Cards and Runes||Challenges||Chapters|