A Little Chat

Casualty on a card selection spell reframes what the mechanic is usually for. Bolted onto a creature or a burn spell, casualty is a straightforward two-for-one: pay a body, get a doubled effect. Here the payoff is subtler, because copying a dig spell does not just find twice as much, it changes the sequence. Cast it clean and you keep one of two cards. Sacrifice a creature and the copy resolves first, so you filter through two, then the original filters through two more (from a library one card deeper), turning a shallow smoothing effect into a genuine four-card dig for two of them. The sacrifice, then, buys card quantity out of an effect that normally only buys card quality, and it lets a deck that is already leaking creatures to combat or a sacrifice engine convert that fodder into the exact answer it needs. Being an instant matters here: this is a spell held up on the opponent's end step or fired off when a board wipe is already incoming, spending a creature that was about to die anyway. Its natural home is a deck that treats bodies as currency rather than assets, where the cost side of casualty stops reading as a cost at all and becomes a second use for something already spent.