Smiting Helix

Lightning Helix rerouted through the graveyard, with the two casts deliberately gated behind different colors. The front half is a straight mono-black sorcery, priced up from the instant it echoes: four mana instead of two, sorcery speed instead of instant. The flashback cost is where the design gets clever, because it demands red and white, the exact colors of the drain-and-burn it imitates. This is built for a Mardu shell that wants to fire the same removal off twice: black pays the entry, Boros pays the encore. That split is the whole reason the card lives in three colors rather than one, a spell you cast with one identity and rebuy with another. The exile-after-flashback clause supplies the friction, capping the loop at one return before the card is gone for good, so there is no engine to assemble here, just a second removal spell you draw out of the yard instead of the library. The rate on either half is forgettable in isolation; getting both across two turns is the point, and the graveyard becomes a resource the deck can spend a follow-up removal spell out of without ever having to redraw it.