(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)
At the beginning of your first main phase, add . Spend this mana only to cast Room spells and unlock doors.
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(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)
When you unlock this door, create an X/X blue Spirit creature token with flying, where X is the number of unlocked doors among Rooms you control.