Door Stop

Effects

While held, the last door Isaac went through stays open, allowing him to leave the room even if enemies are in it.
- Does not prevent doors from closing due to other triggers, e.g. a (Challenge Room) Challenge Room door will still close upon opening a chest.

Does not work on (Secret Room) Secret Room openings.
Does not work in Greed Mode.
- (Added in Repentance) Cannot spawn in Greed Mode.
This allows Isaac to leave rooms, including boss rooms, if the fight goes poorly.
- This becomes particularly useful in (The Void) The Void, where there are multiple boss rooms; Door stop lets the player peek behind each boss room, and thus able to decide whether to face (Delirium) Delirium or other bosses first.
Leaving immediately after enemies have spawned gives the player information on the fight, potentially improving decision making.
If a (Devil Room) Devil Room has a (Krampus) Krampus fight in it, Isaac may choose not to fight him and leave.
If an Angel fight is started in an (Angel Room) Angel Room the door will close and prevent leaving despite the Door Stop.
If (Greed) Greed spawns in a Secret Room or (Shop) Shop, Door Stop can be used to leave and come back to fight Greed again to potentially get more than one (Steam Sale) Steam Sale.
Does not affect (Mom) Mom's boss room.
Can be used to reset (Holy Mantle) Holy Mantle shield. Very useful playing as (The Lost) The Lost.
(Removed in Repentance) If a room contained champion enemies, upon leaving and re-entering the room, all previous champion enemies will have turned to regular enemies.
Cannot be used to escape (Boss Rush) Boss Rush after the fight has started.
Cannot be used to escape the (Mega Satan) Mega Satan fight.