Bontu's Last Reckoning

The cheapest unconditional board wipe black has ever offered, and the price is written in mana you have not spent yet. Most sweepers in its band ask you to pay full freight on the turn you cast them; this one discounts the front end by mortgaging your next turn, since the lands you control will not untap during your following untap step. The design is a clean exchange of tempo for rate: you get the effect of Damnation a turn early, and in return you surrender a turn of development, removal, and interaction. That window is the whole strategic axis. Casting it on an empty board to preempt an opponent's curve is reckless; casting it from behind, already tapped out, with nothing the next turn's lands would have powered anyway, is when the drawback nearly evaporates. What genuinely offsets the fallow untap step is mana that lives outside the restriction: artifact accelerants, Treasure, rituals cast the same turn. A pure spell-based control deck actually suffers most, since holding up interaction the following turn is exactly what a stalled land base forbids. Note the clause is unconditional on land type: creature-lands offer no escape, both because they will not untap and because animating one before the wipe just feeds it to the sweeper. A sorcery-speed reset that asks you to read the game two turns deep is rarer than the rate suggests, and that foresight, not the mana, is the real cost.