Slaughter Pact

The pact mechanic's whole conceit is borrowing against your future: the spell costs nothing the turn you cast it, and the bill comes due at your next upkeep or you simply lose. That structure turns a black removal spell into a tempo instrument. You can hold up zero mana, untap into a topdeck, and still kill a nonblack threat at instant speed; the cost has been deferred to a window where you control the timing. The destroy clause itself carries no toughness limit and no exile rider, though a regeneration shield still saves the target, since the spell never says it can't be regenerated. The genuine cost is structural, not numeric. The deferred payment forces a sequencing question every time you cast it: can you guarantee will be available on your next upkeep, after the lands you control have untapped, accounting for everything an opponent might do in between? Land destruction, a forced sacrifice of your lands, a Stone Rain on the wrong turn can all turn a free removal spell into a concession. The danger lives in the payment clause, not in the trigger: countering the delayed triggered ability outright with a Stifle effect strips the obligation entirely, so you keep the kill and owe nothing. Most pacts ask you to bet the game will still be normal one turn from now. This one usually pays for itself, because killing the creature buys the time to find three mana; the rare exception is the game where it does not, and you have written the loss into the spell yourself.