Smoldering Stagecoach
The five toughness on a body whose power is entirely deck-driven does the structural work: this Vehicle can afford a durable back end precisely because its offense scales with a graveyard you are actively burning through, so it holds up while the spells pile up. The attack trigger is the reason to run it, granting cascade to your next instant and your next sorcery in the same turn. Sit with that tension: cascade is normally a spell-level keyword baked in at printing and paid for up front, and here a Vehicle hands it out retroactively, mid-combat, to whatever you cast after declaring the attack. Crew 2 is a low tax to unlock a turn that can chain a swing, two cascade triggers, and a power count that climbs with each spell you resolve. The self-referential loop is the whole point: the same instants and sorceries feeding the graveyard to pump the power are the fuel for the cascade payoffs, which means the deck has to be casting spells aggressively rather than hoarding them. It rewards a spellslinger shell that treats its graveyard as a live resource rather than a dead pile, and turns the attack step into a value-generating window instead of a bare damage clock.

