- By dropping a card, rune, or pill in a room with no other pickups, then using D1, this item can function similarly to Blank Card, Placebo, and Clear Rune.
- Rune of Jera can not be duplicated.
- Mimic Chests will not be duplicated.
- A normal Chest may be duplicated into a Red Chest or a Mimic Chest.
- 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 Purse, Belly Button, or Smelter.
- It is possible to duplicate shop pickups that have not been purchased yet.
- With Car Battery, it is possible to infinitely generate Lil' Batteries from a single Lil' Battery.
- In combination with a 48 Hour Energy and Paper Clip, the initial Locked Chests on Chest can be infinitely duplicated and opened.
- In Greed mode, if a Lil' Battery appears in the Shop and a 2 of Diamonds is acquired, infinite money can be gained by duplicating the Two of Diamonds.
- With a ? Card and Schoolbag, single use items can be used an unlimited number of times by duplicating the card.
- D1 is the only dice item that doesn't re-roll anything.
- As such, its description, in certain cases, can be ironic, as the outcome is entirely predictable if there's only one pickup. This makes sense because the dice only has one pip on each of its 6 sides.
- As an exception, Spindown Dice, although it technically does re-roll items, has a controlled and consistent result.
- D1 is the only standard dice item that doesn't have the respective number of sides as outcomes, but rather, just a D6 with all sides having singular pips. Rather, an actual D1 would be more accurately pictured as a Mobius strip or a sphere.
|The Binding of Isaac: Rebirth|
|Achievements||Attributes||Bosses||Cards and Runes||Challenges||Chapters|