Glassworks / Shattered Yard - Duskmourn: House of Horror (DSK)

Enchantment - Room

Common - Duskmourn: House of Horror (DSK)

(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.)

Glassworks - 2, Red

When you unlock this door, this Room deals 4 damage to target creature an opponent controls.

Shattered Yard - 4, Red

At the beginning of your end step, this Room deals 1 damage to each opponent.