The Twins

The Twins is a trinket added in The Binding of Isaac: Repentance.

Effects

 * Adds a 50% chance to duplicate one of Isaac's familiars when entering a new room.
 * If Isaac has no familiars, spawns or  instead.

Synergies

 * : 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.

Interactions

 * Movement-mimicking familiars: Duplicated familiars will follow the original on the same delay.
 * In the case of, 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:
 * : 1 room (will give a coin every time it’s duplicated)
 * /: 2 rooms
 * //: 5 rooms
 * : 6 rooms
 * : 7 rooms
 * Because and ’s chances to spawn pickups are independent from the total number of rooms cleared with them, they have an extra chance to pay out in any room they’re duplicated in.
 * /: Familiars given by these items can be duplicated as normal.
 * ////: The pickup count of duplicated familiars is not remembered when they go away.
 * /: Upgrades the familiar instead of duplicating it.
 * /: 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.
 * //: The duplicate will always be at its first stage.
 * : Despite the fact that it can be duplicated, Isaac will not keep the 1up if he dies while it's duplicated.
 * : 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.
 * : 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.
 * : The damage multiplier from standing in the aura of multiple Succubi multiplicatively stacks.
 * : The duplicated familiar will be randomly generated instead of copying the original.
 * : Duplicate poops will also drop when Isaac takes damage. The bonuses from standing in the aura of multiple white poops does not stack.
 * : An extra +1 luck will be given for every duplicate.
 * : The friendly the duplicated egg spawns depends on how many consecutive rooms cleared the duplicate persisted for.
 * /: 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.
 * : Familiars given can be duplicated as normal.
 * : Keeper cannot be duplicated, as he is considered a character, not a familiar.