Cloud Key (Retro Schematic) (Serialized) [The Brothers' War Retro Artifacts] Treasure it enters with three additional

it enters with three additional +1/+1 counters on it

"Unskin these impure bodies

It's nearly the size of the Null Moon

it gets +3/+3 and gains indestructible until end of turn

Set: Kaladesh Inventions Type: Artifact Rarity: Mythic Cost: {2} Each spell costs {3} more to cast except during its controller's turn

Cloud Key (Retro Schematic) (Serialized) [The Brothers' War Retro Artifacts] Treasure it enters with three additionalSet: The Brothers' War Retro Artifacts Type: Artifact Rarity: Rare Cost: {3} As Cloud Key enters the battlefield, choose artifact, creature, enchantment, instant, or sorcery. Spells you cast of the chosen type cost {1} less to cast. "A key only unlocks a door. Its wielder must choose whether to cross the threshold." *Hurkyl's Metaphysics, vol. II*