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D1 is an unlockable activated item added in Afterbirth †.
- By dropping a card, rune, or pill in a room with no other pickups, then using D1, this item can function similarly to Blank CardHas the same effect as the card or rune currently held by Isaac. and PlaceboWhen used, copies the effect of the pill Isaac is currently holding without consuming it. Does not copy the effects of cards or runes..
- Jera can not be duplicated.
- Mimics will not be duplicated.
- A brown chest may be duplicated into a red chest or a mimic.
- Opened chests will be duplicated into an unopened copy.
- A duplicated trinket is mostly useless, as you cannot pick up two of the same trinket even with Mom's PurseAllows Isaac to hold 1 additional trinket./ Belly ButtonDrops a random trinket. Grants a second trinket slot. or SmelterConsumes Isaac's currently held trinket and applies its effect permanently..
- However, with "consumable" trinkets such as Store CreditThe next store purchase is free. The trinket disappears on purchase. or Bag LunchTaking damage has a small chance to destroy the trinket and spawn Lunch., it can be extremely powerful.
- It is possible to duplicate shop pickups that have not been purchased yet.
- With Car BatteryCauses Isaac's activated item to activate twice on each use., it is possible to infinitely generate battery pickups from a single Lil' Battery.
- In combination with a 48 Hour Energy and Paper ClipGolden Chests can be opened without using a key., the initial golden chests on The Chest can be infinitely duplicated and opened.
- In Greed Mode, if a battery appears in the shop and a 2 of DiamondsDoubles your coins. If you have no coins, gives you 2 instead. is acquired, infinite money can be gained by duplicating the Two of Diamonds.
- D1 is the only dice item that doesn't re-roll anything.
| D1Duplicates a random pickup in the room.
| D4Rerolls all of Isaac's items.
|| The D6Allows Isaac to re-roll collectible items in the current room into other items, depending on the current room's Item Pool.
|| D7Restarts the current room and brings back all enemies, allowing more rewards to be acquired by completing the room.
| D8Re-rolls Isaac's speed, range, tears, and damage.
| D10Rerolls the enemies in a room. Only rerolls enemies that are still alive (does not spawn new enemies).
|| D12Re-rolls all rocks in the current room into other random objects, such as bomb rocks, metal blocks, TNT, or poops.
| D20Rerolls all pickups in the current room.
|| 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.
|| D InfinityGrants a random dice item that changes each use.|