Surgical Suite // Hospital Room (DSK-034) - Duskmourn: House of Horror

(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, return target creature card with mana value 3 or less from your graveyard to the battlefield.

(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 attack, put a +1/+1 counter on target attacking creature.