Bottle of Suleiman

Wizards rarely lets a card make a player gamble for so much at once, and this is the printing that drew the template for everything that came after. Five mana total (four to cast, one to crack) buys a 50/50 between a 5/5 flying Djinn and five damage to your own face, with nothing hidden in the math: the upside is priced at a real cost, the downside at a real cost, and that symmetry is exactly why the card has outlived its power level. The modern design language around coin flips (Krark's Thumb, Mana Clash, the Okaun and Zndrsplt pair) all descends from the premise this card established, that a flip is a legitimate game action carrying a legitimate game cost. The flavor does as much work as the mechanic: a bottled djinn that grants a wish or kills you for asking welds story to rules tightly enough that the card persists in memory long after its rate stopped mattering, and the Arabian Nights frame around it is part of why it stuck. It belongs to the stretch when Magic was still deciding which forms of variance it wanted to keep, and it stands as proof that some of those forms are still in the game.