Mana Clash

The damage output is unknown at cast time, and the spell makes that uncertainty its whole proposition: the loop runs until both players hit heads on the same flip, which means it can do nothing, can do twelve, and resolves no rate you can evaluate before you commit the mana. Red burn is normally priced on certainty (one mana, a fixed number, done), and this trades that certainty for a probability tree with no off-switch. The symmetry is the sharper friction. Every tails on your own coin is a point off your own life total, so what looks like an aggressive spell is actually a mutual gamble where both players are exposed to the same coins, and the damage only ever reaches players, never creatures. It comes from the game's early years, when designers were still testing whether players would tolerate outcomes they could not sequence around; the verdict was largely no, and the coin-flip burn experiment did not propagate. What survives here is a pure expression of that experiment: a spell whose entire text is a coin and the willingness to let it decide, with no line to plan and no number to count on. At the table it plays as a dare more than a removal answer, the kind of card you cast to watch the flips happen. It read as a curiosity then, and it reads as one now.