Secret Arcade // Dusty Parlor (DSC-010) - Duskmourn: House of Horror Commander

(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.)
Nonland permanents you control and permanent spells you control are enchantments in addition to their other types.

(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.)
Whenever you cast an enchantment spell, put a number of +1/+1 counters equal to that spell's mana value on up to one target creature.