Serpent of the Pass

The whole design hinges on the graveyard doing double duty. A 6/5 body priced at seven mana is deliberately overstated at face value, because the card is built to be paid for with cards already spent: each noncreature, nonland card in your graveyard shaves a mana off the cost, so a deck churning through instants, sorceries, and Lessons can land this well below its printed rate. The flash clause is gated behind a distinct condition (three or more Lesson cards in your graveyard), which is a telling piece of construction: it ties the tempo upside not to raw graveyard count but to a specific card type, rewarding a deck that has committed to Lessons as a subtheme rather than one that has merely durdled its way to a full graveyard. That split gives the card two separate axes: a cost engine that scales with any spent noncreature spell, and an instant-speed window that only opens for a dedicated Lesson shell. What it wants is a graveyard full of the right kind of exhaust, and the flash mode converts a clunky finisher into an ambush that can drop as a turn winds down or sit in reserve until interaction is spent and the moment to commit arrives.