Prohibitory Signboard is an active item in Reverie: Make Good Omissions, a mod for The Binding of Isaac.

While held Indicates walls that can create a Red Room with a red outline.

If a room would otherwise yield no reward, spawn a Cracked Key.

Grants a 25 / (DisabledRoomTypeCount + 1)% chance to activate the effects of Soul of Cain once upon clearing a room.

If the room type of an unexplored Red Room is disabled, it will be another room type instead when Isaac enters it.

On use Selects one room type. If the selected room type is not disabled, disable it; otherwise, enable it.

The selectable room types are as follows:
• Normal Room
• Angel Room
• Arcade
• Bedroom
• Curse Room
• Devil Room
• Dice Room
• Library
• Mini-Boss Room
• Planetarium
• Sacrifice Room
• Secret Room
• Shop
• Super Secret Room
• Treasure Room
• Vault

Prohibitory Signboard can be found in the following item pools:

The following tags are applied to this item:

The following special synergies and interactions for Prohibitory Signboard have been documented.

* Note that not all possible synergies and interactions are listed here.

• Download Reverie: Make Good Omissions from the Steam Workshop.