D4

### Collection Grid

*(page 3, column 9, row 8)**(page 3, column 19, row 2)**(page 3, column 20, row 2)*

### Unlock Method

 Blow up 30 Slot Machine

**D4** is an unlockable activated item.

## Effect

* Upon use, re-rolls each of Isaac's passive items into new ones.
	+ The new items will be drawn from the Treasure Room item pool.
		- The game attempts to match the new item to the pool where the item it replaces was acquired but this is glitched, see the Bugs section.
	+ If health upgrade items are removed by a reroll, the health they granted is subtracted.

## Notes

* The D4 does not re-roll , , , , , , , or .
	+ The D4 can reroll Dead Cat and Halo of Flies, but will not reroll , , ,  and , and glitched items, in addition to the above.
	+ Note that  can be re-rolled into, but can't be re-rolled out of.
* The D4 does not remove traits or abilities inherent to a character, i.e.  Azazel's Brimstone-like attack,  Lilith's Incubus or  The Forgotten's bone attack.
	+ Starting items from Challenges will also not be rerolled
	+ The Lost's  is included.
* Items that grant pickups (like  or ) do not remove their bonuses when rerolled.
* The D4 can grant items that have not yet been unlocked.
* The items gained by the D4 count towards the collection page.
* Multiple copies of the same item (as generated by , the Debug Console, or gathering them from multiple item pools (e.g.  from both the Shop and Greed) will each be rerolled into a different item,  even though the duplicates are not present on the pause screen.
* There is a small chance that D4 will not reroll every item: the game makes a number of attempts to reroll each item, but if they all fail to produce a new item that is available and applicable, the original remains unchanged.
* Smelted/Swallowed trinkets (via ,  or Gulp!) will not be rerolled.
* Items rerolled away from Isaac do *not* return to circulation and can't be encountered again.
	+ Items rerolled away are returned to circulation and can be encountered again later in the run.
* If Isaac has a transformation, its effects will not be lost upon re-rolling.
	+ Transformations are removed with the items being rerolled.
* If it is unlocked,  The Lost starts with this item along with spectral tears and flight. Using it *will* reroll .
* The D4 does not give hearts that would be otherwise gained from item pickups, but will remove previously collected health upgrade items.
* If used while playing as  Jacob and Esau or  Tainted Lazarus, it will only reroll the items on the character that used it.
* Tainted Isaac can avoid having their health subtracted form re-rolling health up items by dropping health items for full inventory before rerolling.

## Synergies

* : Locusts created by Abyss are not rerolled.
* : Removes all of Isaac's wisps and gives him one random wisp for every two items rerolled. Book of Virtues will not be rerolled in the process.

## Interactions

* : Instantly re-rolls Isaac's items twice, which doubles the speed at which the item pools are exhausted and transformations are achieved.
* Every  produced using  count as an item for rerolling to the D4. Because health usually is not removed in rerolling items this is useful to increase the number of items at the expense of the item pool.

## Trivia

* The image of the D4 that appears on activation is incorrect; it shows the numbers 9, 7, and 8 on the right face of the die, when it should depict numbers consistent with the left face (i.e. 1 at the top, 3 at the front, and 4 at the right).

## Gallery

* 3DS The icon of D4 as seen on the lower 3DS screen.
* Splash image which appears when D4 is activated.