Binding of Isaac: Rebirth Wiki

(except in Rebirth)
This article is about the glowing hourglass. For the normal version of this item, see The Hourglass.

Glowing Hourglass is an activated item added in The Binding of Isaac: Afterbirth.

Effect[ | ]

  • On use, Isaac will be returned to the previous room and everything that happened in the current room will be undone.
    • Health, bombs, coins, keys, cards/runes/pills, items, and trinkets will be restored.
    • Score and Time will reset, (except in Repentance) but about one second will be spent in an unskippable animation after use.
    • Most permanent unlocks will be reverted (see below).
  • (in Repentance) Can only be used 3 times on each floor, after which it functions like Collectible The Hourglass iconThe Hourglass until a new floor is entered.

Notes[ | ]

  • The Glowing Hourglass is very useful for finding out hidden information. For example, the player can grab every pill on the floor and use them all in the same room, then activate the Glowing Hourglass to figure out which pills are worth or not worth taking. Isaac can bomb walls with potential secret rooms, then go back in time if he fails to find one. If Isaac has Curse of the BlindCurse of the Blind, Glowing Hourglass can be used to pick up or purchase an unknown item to see what it is, then decide whether or not to undo picking it up. It can be even be used in extremely creative ways, such as popping a XXI - The World card and screenshotting the map, then going back in time to get the card back. After all, time travel is an extremely powerful ability, but it requires skill and creativity to use it effectively.
  • Does not affect the chance for a Devil RoomDevil Room, Angel RoomAngel Room, or a portal to (in Afterbirth † and Repentance)The VoidThe Void to spawn (it will not spawn if it didn’t initially).
  • If used in a Devil Room or Angel Room, the door to it has its normal chance to close.
    • If used on the Boss RushBoss Rush after the time limit expires, the door will not remain open when sent back to the boss room.
  • If Isaac goes into a Devil/Angel room, sees undesirable items, activates the Glowing Hourglass, and the Devil/Angel door doesn't stay open, then the game will think that isaac missed the Devil/Angel deal on the floor, and will thus increase your chance of getting one on the next floor.
  • Finding the Glowing Hourglass in a room and using it to undo picking up Glowing Hourglass will preserve its charges, letting you reset that room infinitely.
    • If you already have Glowing Hourglass, then you can still achieve this effect by replacing the Glowing Hourglass with a different active item, exiting the room, then re-entering and using the Glowing Hourglass.
    • (except in Repentance) Doing this will remove the charges of the returned active item.
    • (except in Repentance) If there is a Lil' Battery in a Shop, the Glowing Hourglass can be used infinitely, by entering the Shop without a charge and using the Lil' Battery to recharge and exit the shop. This is useful for duplicating temporary familiars or filling up the Donation Machine, among other uses.
  • (in Rebirth and Afterbirth) Isaac's temporary familiars (Blue Flies and Spiders) duplicate when using the Glowing Hourglass.
    • For example, if combined with Collectible The Battery iconThe Battery or Collectible Sharp Plug iconSharp Plug while Blue Spiders are present, this combo can generate an infinite army of Blue Spiders.
  • (in Repentance) Each use of Glowing Hourglass that does not move Isaac to a different room than the one he is currently in will duplicate some familiars that persist through rooms. This also includes activating the Glowing Hourglass in the first room of each floor. (This is a bug)
    • Familiars that can be multiplied:
    • There is a limit of 64 familiars that can be gained through this method.
  • The delayed effect of the I'm Excited pill will still occur after rewinding.
  • (except in Repentance) The Retro Vision Pill will continue to affect the game even after using the Glowing Hourglass.
  • (in Rebirth and Afterbirth) Does not turn a character back into another should they have been revived by Collectible Ankh iconAnkh, Collectible Lazarus' Rags iconLazarus' Rags, or Collectible Judas' Shadow iconJudas' Shadow.
    • (in Afterbirth † and Repentance) Character changes are reverted by Glowing Hourglass.
  • (except in Repentance) Does not return keys or health used to enter special rooms.
    • If a bomb is used to enter a Secret Room, the Secret Room is entered, and the Glowing Hourglass is used, the Secret Room door will stay open and the bomb will not be refunded.
  • (except in Repentance) Does not return extra lives.
  • (except in Repentance) Using a JokerJoker and then the Glowing Hourglass to return does not guarantee a Devil Room for every floor as the Joker card does not get refunded. This applies to all teleport cards. The reason for this is that you immediately change rooms after the Joker card is used, as such reverting to before it was used is impossible.
    • (in Repentance) Teleport cards like JokerJoker can be refunded. However, if used on the first room on the floor, the Glowing Hourglass will be uncharged when you return.
  • (in Repentance) Using the Glowing Hourglass after entering a new floor will teleport you back to the boss room of the previous floor.
    • Going back to the previous floor will transform Glowing Hourglass into Collectible The Hourglass iconThe Hourglass for the rest of that previous floor. Going back to the new floor recharges the Glowing Hourglass, which allows for infinite usage of Glowing Hourglass on the starting room of a new floor.
  • (in Repentance) Character Bethany iconBethany's soul heart counter does not get reset upon activating this item.
  • (in Repentance) If Character Tainted Jacob iconTainted Jacob is hit by Esau, using the Glowing Hourglass will return him to normal form in the previous room.
  • (in Repentance) The guaranteed angel room chance can be preserved if the item is used after entering the first devil room.
  • (in Repentance) When Isaac enters Boss The Beast ingameThe Beast fight, Glowing Hourglass will transform into a fully charged Collectible The Hourglass iconThe Hourglass.
  • (in Repentance) May be helpful for finding PlanetariumPlanetariums, as it lets the player effectively skip item rooms while also seeing if what's inside them is worth taking.
  • (in Repentance) If Isaac enters a Planetarium for the first time and then uses Glowing Hourglass to leave, the chance of a PlanetariumPlanetarium generating on future floors can be preserved, effectively allowing Isaac to reroll his Planetarium until a desired item is found. The likelihood of this being useful is rather low, however, due to Planetariums being rather rare.
  • (in Repentance) The Boss Challenge RoomBoss Challenge Room re-rolls bosses on using the Glowing Hourglass.
  • (in Repentance)PerfectionPerfection is still able to drop if the Glowing Hourglass is used to reset damage, and will be brought back by the Glowing Hourglass if used to reset a damage taken while holding it.
  • (in Repentance) If used in the starting room of BasementBasement I without having entered any other rooms, Isaac is taken to the first room of HomeHome. If used again in this room without having entered any other rooms, the room will be rewound to when you first entered it. In a normal game, this is only possible by getting the item as a starting item from Character Eden iconEden/ Character Tainted Eden iconTainted Eden, or from Collectible Eden's Blessing iconEden's Blessing. Having Collectible Schoolbag iconSchoolbag and obtaining Collectible R Key iconR Key and resetting the run also makes this possible.
  • The Glowing Hourglass affects permanent unlocks, event counters, boss kills, etc. differently depending on what is being reset:

Synergies[ | ]

  • Any reroll item/collectible: Items in the room can be rerolled, and if the result is undesirable, then Isaac can go back in time to save whatever was used to reroll. However, note that activating the reroll on the same items again will result in the same items being generated as the first time. Rerolling different items from the same type of room (such as going to a different Shop) will result in the reroll effect creating new and different items. This technique is useful for saving charges on items like Collectible The D6 iconThe D6, or getting multiple options with consumables like the Rune of PerthroRune of Perthro.
  • Anything that spawns an item such as (in Afterbirth † and Repentance)Collectible Mystery Gift iconMystery Gift/(in Repentance)XVII - The Stars?XVII - The Stars?: After the player activates them, they can then go back in time if the item is undesirable. However, unlike reroll effects, using something that spawns an item/collectible will always generate that same item, dependent on the room type, even if the player goes to a different one in the future. For example, activating XVII - The Stars? in a Secret Room will create two items from the Secret Room item pool, and even if the player goes to the next floor and uses it again in a new Secret Room, the same exact items will be generated. So, the best way to use something that spawns an item is to activate it in rooms with different item pools (Secret, Devil/Angel, Treasure, Shop, etc.) and see which item would be the best before accepting it.
  • (in Rebirth and Afterbirth) ? Card? Card: Allows for infinite usage as the ? Card gets refunded upon usage.
  • (except in Repentance) Collectible 9 Volt icon9 Volt: Clearing any room is enough to instantly recharge the hourglass, allowing infinite tries for the best outcome.
  • (in Rebirth and Afterbirth)Collectible The Battery iconThe Battery: When the item is double charged and used, it will also refund the used extra charge bar, making it possible to use it endlessly.
  • (in Afterbirth †)48 Hour Energy pill: Allows for infinite usage as the pill gets refunded upon use.
  • (in Afterbirth †)Collectible Sharp Plug iconSharp Plug: Allows for infinite usage as long as you have more than 2 full hearts as the hearts used to charge will be refunded upon use.
  • (in Afterbirth †)Collectible Habit iconHabit: Allows rooms to be repeated infinitely as long as Isaac has enough health to take two hits, which are refunded on use.
  • (in Afterbirth †)HairpinHairpin: If Hairpin is held while entering any Boss Room for the first time, Glowing Hourglass may be used indefinitely on said room to repeat the fight until you beat it.
  • (in Afterbirth †)Collectible Moving Box iconMoving Box: Using the Glowing Hourglass after retrieving it from Moving Box will not deplete its charge.
  • (in Afterbirth †)Collectible Curse of the Tower iconCurse of the Tower: If used quickly after taking damage, Troll bombs will spawn in the previous room. If you have the Safety ScissorsSafety Scissors, these can be harvested as normal.
  • (in Afterbirth †)Collectible Crooked Penny iconCrooked Penny + Collectible Schoolbag iconSchoolbag: If there is a battery and an item in the same room, you can multiply items an infinite number of times. Every time you fail the Crooked Penny flip, you can activate the Glowing Hourglass, go back in, grab a battery, then try again. Every time you succeed a flip, you must leave the room and enter it again to "save" your progress.
  • Collectible More Options iconMore Options: If used after entering the Treasure Room for the first time, upon reentering the room, the items may change. The reroll is not always guaranteed as Glowing Hourglass is causing the Treasure RoomTreasure Room to alternate between a set number of different More Options room layouts on a given floor with repeat layouts offering the same items.
  • (in Repentance) If Character Tainted Eden iconTainted Eden's active item re-rolls into Glowing Hourglass, it can be used immediately to return Tainted Eden to their previous state. This allows the player to have practically infinite attempts to keep their loadout of passive items as long as they travel back in time before being hit again.
  • (in Repentance)Collectible Book of Virtues iconBook of Virtues: Any wisps lost in the previous room will be restored, and an additional Glowing Hourglass wisp will be added on the middle ring. This wisp's tears have a 30% chance to petrify enemies.
    • While playing as Character Tainted Eden iconTainted Eden and rerolling an active item into the Glowing Hourglass, you can infinitely spawn wisps as much as possible until you reroll it again.
  • (in Repentance)Collectible Duality iconDuality: The doors to the Devil RoomDevil Room and Angel RoomAngel Room stay open if you use the Glowing Hourglass inside their rooms, so Duality lets you check the items of both of them before deciding which room to use, provided two charges are still available by the end of the floor.
  • (in Repentance) Collectible Forget Me Now iconForget Me Now + Collectible Schoolbag iconSchoolbag: Using Forget Me Now will fully recharge Glowing Hourglass on the new floor, using Glowing Hourglass after that will take Isaac back to the previous room while also giving back Forget Me Now. This allows for infinite usage of Glowing Hourglass as well as infinite retries of any room as long as Forget Me Now is used before the room is cleared.
  • (in Repentance)Collectible Saturnus iconSaturnus: Using the Glowing Hourglass will activate the effect of Saturnus again, essentially allowing for double the amount of orbiting tears, if the player returns to a room, where the tears created by Saturnus were not destroyed.
  • (in Repentance) If activated while under the effect of Soul of Azazel, as long as you had the consumable in the previously visited room, you will keep the Megablast effect while having another copy of the soul in your inventory.

Interactions[ | ]

  • (in Repentance)Collectible Bag of Crafting iconBag of Crafting: The bag's contents will be reverted to its previous state. Additionally, Bag of Crafting cannot be used to create Glowing Hourglass.
  • (except in Repentance)Collectible The Battery iconThe Battery: Glowing Hourglass will receive a maximum of two full charges as normal, however, using the item twice consecutively will not result in the player being teleported two rooms previous, only one. This means that if Glowing Hourglass is used twice in succession, they will rewind as normal with the first use to the previous room, then, upon second use, everything will be rewound, but the player will not be teleported to the room previous to the one they just teleported to and will instead find themselves teleported to the room they are currently in. Rewinding works as normal, but teleportation is limited to the last room visited.
    • (in Repentance) The battery has no effect on Glowing Hourglass when it is not in Collectible The Hourglass iconThe Hourglass form.
  • Collectible Car Battery iconCar Battery: No effect.
  • (in Afterbirth † and Repentance)Collectible Schoolbag iconSchoolbag: Losing your Schoolbag while Glowing Hourglass is in your second active slot will drop it on the ground fully charged.
  • (in Repentance) Character Tainted Jacob iconTainted Jacob: Using this item in a room where Dark Esau has spawned will cause him to remain with the player after teleporting, but once enough time has passed, he will suddenly disappear and respawn elsewhere. This may be a bug.
  • (in Afterbirth †)Collectible Void iconVoid: It is impossible to absorb a Glowing Hourglass pedestal without using the item and preventing it from having been absorbed.
    • (in Repentance) The Glowing Hourglass is absorbed like normal. Subsequent uses of Void send Isaac back to the previous room, reverting most changes, nullifying many other effects that Void may have absorbed. This will prevent you from consuming any further powers, as you will instead reset the room. This effectively turns Void into a charged version of Glowing Hourglass, allowing potential infinite uses with items like 48 Hour Energy pills, Collectible Sharp Plug iconSharp Plug, Collectible Habit iconHabit, HairpinHairpin, Collectible 4.5 Volt icon4.5 Volt, or a room with a Lil' BatteryLil' Battery.

In-game Footage[ | ]

Trivia[ | ]

  • Prior to Afterbirth+ Booster Pack 5, Glowing Hourglass would turn into Collectible The Hourglass iconThe Hourglass after being used 5 times.
  • Prior to Repentance V1.7.9a, Glowing Hourglass was called "Glowing Hour Glass".

Bugs[ | ]

Bug Bug! For some reason, having ErrorError trinket with you will make your familiars "respawn" each time you use Collectible Glowing Hourglass iconGlowing Hourglass, which leads for some interesting interactions. For example, (in Afterbirth † and Repentance)Collectible Buddy in a Box iconBuddy in a Box and (in Afterbirth † and Repentance)Collectible 7 Seals icon7 Seals will change their forms each time leap, and the (in Repentance)Collectible Star of Bethlehem iconStar of Bethlehem will change its position to the room where you ended up after the time leap, allowing you to move it where you want it to be.
Bug Bug! Going back in time will add one more copy of each familiar that were created by Collectible Monster Manual iconMonster Manual for the duration of the room you ended up in, regardless if you have it with you or not. Exiting this room and using Collectible Glowing Hourglass iconGlowing Hourglass again will add another copy for each time leap you do, it will still last untill you will exit that room and will be reset afterwards.
Bug Bug! Going back to the starting room will undo some map-revealing effects, such as Collectible The Compass iconThe Compass.
Bug Bug! (except in Repentance) If a new game is started and Character Eden iconEden begins with this item, using it in the first room will remove Eden's starting items.
Bug Bug! Using the reworked (in Repentance)Collectible Glowing Hourglass iconGlowing Hourglass in the starting room in Greed mode only Greed mode or Greedier mode only Greedier mode will result in a game crash.