Box of Friends

Box of Friends is an unlockable activated item added in The Binding of Isaac: Afterbirth.

Effect

 * Upon use, it adds one copy of each of Isaac's familiars for the duration of the current room.
 * If Isaac has no familiars, a will spawn for the duration of the current room.

Synergies

 * / / : Upgrades the cube/ball for the current room. This can be used to easily unlock the Super Meat Boy and Bandage Girl achievements.
 * Cubes of Meat from cannot be duplicated or upgraded.
 * : When used upon entering a room, Box of Friends eliminates the item delay, which allows Isaac to launch Bob's Brain immediately.
 * : Adds two copies of each familiar.
 * : Familiar will be copied.
 * : Creates additional Incubus familiars, which share the same tear modifiers as the player.
 * : Each copy of Multidimensional Baby follows the previous copy with a 2.5-second delay.
 * : Very useful on Greed mode, as using it will add an attacking fly, killing enemies and bosses very quickly.
 * : All around useful, can charge box of friends mid room to spawn more of itself creating a charging loop.

Interactions

 * / : Familiars are multiplied but do not give Isaac additional lives.
 * Flies gained from Abyss do not count as familiars for Box of Friends, and are not copied.
 * : If used before taking damage, the white fly will circle Isaac. However, multiple white flies cannot be spawned, so using Box of Friends after taking damage or using it multiple times in a room creates no effect.
 * : Creates another randomly generated familiar, rather than copying the same one.
 * : Will spawn a level 1 Bumbo regardless of the original Bumbo's current level.
 * / Eve's Bird Foot / Isaac's Head / ???'s Soul: These familiars are not copied.
 * The Seraphim familiar is not copied.
 * : Duplicates the Head circling Isaac's body. Only one head will shoot tears.
 * : All poop familiars turn into white poop at the same time, and their effects are accumulative. A new poop familiar appears even if the previous poops have been used up.
 * Isaac's Head: Not copied.
 * / Super Bum: Not copied. They will not spawn a if no other valid familiars are found, unlike other familiars that aren't copied.
 * / : Key pieces are multiplied, but do not complete the other half.
 * / : Knife pieces and the knife are not copied.
 * : The familiar itself doesn't appear, but instead, it decreases tear delay by 2 (effective tears up) when used, without needing to take damage.
 * : Familiars spawned by Monster Manual are not copied. It will still spawn a if a familiar from Monster Manual is generated and there are no other valid familiars that can be duplicated.
 * : No effect.
 * Pickup generation familiars: The copied familiars will drop pickups independently.
 * : Existing Quints familiars will not be duplicated, nor more will be created. If Isaac has no other familiars, the generated Demon Baby will hover with the Quints instead of following Isaac.
 * : A new follower Shade spawns even if Isaac has already absorbed the original.

Trivia

 * The Box of Friends seems to resemble the Lament Configuration of the Lemarchand's box from Clive Barker's Hellraiser.
 * This item used to have a recharge time of 2, until an update on November 4, 2015.
 * When playing in Korean, this item still has a recharge time of 2.
 * In the game files this item's sprite is called "Pandora's Box" by a mistake.

Seed
WL8W DS4S (First Golden Treasure Room)