Rockshard Elemental

Double strike is what turns the morph guessing game into a combat trap. Cast face down, the elemental reads as just another 2/2 in the pile, and an opponent prices their block against that body: they trade a chump into it, or hold back a 3/3 they think dominates the exchange. Flip Rockshard Elemental for and the math inverts in a single step, because double strike on a 4/3 means it deals four during the first-strike damage step. Against most early blockers, that step alone is fatal: the creature dies before it ever assigns damage back, and a chump or a 3/3 is simply gone. The defender was never blocking the creature in front of them; they were blocking something that resolves the combat one full damage step ahead of schedule. That is the cruelty of the design: the face-down state hides not a bigger body but an extra damage window, and first strike makes the ambush land before the trade can play out as the blocker intended. The cost keeps it a setup rather than a tempo play. Seven mana to hard-cast, or the down payment plus a six-mana flip, makes the elemental a turn you spend loading rather than a curve-filler. Efficiency was never its job. The early morph designs traded on the question of what hid under a face-down creature, and this one answered with a body that kills first and asks no questions.