Thousand-Year Storm
The math is the whole appeal: the copy count scales with spells already cast this turn, so the second cast makes one copy, the third makes two, the fourth makes three, and every additional spell adds one more copy than the last. That triangular ramp is the design problem this six-mana enchantment is built around. It offers nothing the instant it resolves, but it does not have to wait a turn cycle to pay out either; the moment it is down, every subsequent instant or sorcery you cast that turn feeds the counter, so a resolve-and-go-off line is entirely possible if you have the mana and the cards in hand. The real skill is sequencing: the cheapest cantrips go first to inflate the multiplier, the lethal spell goes last when every prior cast is fanning out copies behind it. It carries the storm mechanic's promise without the storm keyword, swapping the count-your-spells trigger for a per-cast copy that lets you choose new targets, so a single burn spell or draw spell branches into a spread of independent effects mid-turn, each aimable wherever it does the most work. This is pure build-around: it rewards a deck constructed entirely to chain cheap spells and offers nothing to one that was not.
