Grasping Shadows // Shadows' Lair

The condition is the whole design: an enchantment that rewards you for sending one creature into the red zone by itself, then counts those solo assaults toward its own transformation. Attacking alone is normally the punished play, the choice that walks into removal and blocks with no backup; here it's the trigger that hands your attacker deathtouch and lifelink, so a lone creature both trades up and pads your life total while the enchantment fills with dread counters. Three swings later it flips into a Cave, which resolves the tension it built: the enchantment side gives you a reason to attack solo turn after turn, and the land side converts that accumulated aggression into black mana plus a repeatable, life-paying card draw that spends the counters it collected. The dread counters are the throttle. They gate the transformation up front, then meter out the draws on the back, so the card can't loop indefinitely: each activation on Shadows' Lair burns a counter and a point of life, and when they run dry the engine stops producing cards and quietly becomes a land that taps for black. It's a patient piece that asks you to commit to a single-attacker plan long enough for the enchantment to graduate into the resource it always intended to be.