Sautekh Immortal
The flash is what turns the counter clause from a build-around into an ambush. A base 2/2 for three that scales off deaths this turn wants a board full of corpses to matter, and flash lets it wait for exactly that moment: after combat trades, after a wrath resolves, after your own sacrifice engine has been spinning. Cast it in the second main phase or on your opponent's turn and every creature that has already died feeds the body, so the same board state that would leave a sorcery-speed version stranded becomes its best possible entry point. That is the design tension the card resolves: a payoff that grows with attrition, given the timing tool to arrive only once the attrition has happened. It reads as reactive removal-insurance and blocker-in-a-can more than a proactive threat, which is a rare posture for a creature whose whole appeal is getting large. The counters are permanent once placed, not a temporary buff tied to the turn, so a well-timed flash-in banks the death count into a durable body rather than a fleeting one. In aristocrats and sacrifice-heavy shells, where creatures cycle through the graveyard by the handful each turn, it becomes a reload that punishes an opponent for engaging: swing into open black mana and the blocker that appears is exactly as big as the trade you just forced.

