Oath of Druids

Build a deck that wants to fall behind. That is the perverse instruction at the center of this enchantment: the upkeep trigger only fires when an opponent controls more creatures than you, so the deck constructed around it runs almost no creatures of its own, deliberately staying empty to keep the engine live. An empty board is the cost of admission, and the payoff is cheating an oversized creature directly onto the battlefield from the top of the library while everything above it lands in the graveyard as fuel. That self-imposed constraint is the whole archetype. The recursion-and-reanimation lineage that grew up around it (graveyard payoffs, fatties that want to skip their mana cost, library manipulation to control exactly what flips) made it one of the defining build-around enchantments of its era, powerful enough that the eternal formats where green ramp and broken creatures coexist have largely kept it restricted or banned. The card you reveal matters far more than the rate of the enchantment itself: this is a delivery system, and the deck is whatever you decide is worth delivering for free. The most elegant builds even weaponize the mill, stacking the library so the cards dumped on the way to the creature are precisely the ones you wanted in the graveyard anyway. The enchantment costs two mana and asks one question; the deckbuilder answers it by giving up the entire normal game of playing creatures.