Crystallization

Pacifism that punishes interaction. The first clause is the familiar containment so many white auras provide: the creature can't attack or block, parked harmlessly while you do other things. The second clause is where the design turns predatory. The exile trigger fires when the enchanted creature becomes the target of a spell or ability, which is a narrower and meaner window than it first reads. It does not catch an opponent who simply destroys the Aura: a Naturalize or Disenchant targets the enchantment, not the creature, and removing the Aura frees the body cleanly. What it catches is every other instinct a stalled board invites. The pump spell to push chip damage through, the bounce to reset the lock, the protective shield, the equip-style targeting, even the opponent's own buff: anything that names the locked creature converts that creature into exile fodder. The trap, then, is not the can't-attack clause but the patience it demands. Leave the creature alone and you have a flavorful Pacifism; reach for any targeted answer other than disenchanting the Aura and you have handed your opponent a removal spell. The hybrid green-or-blue pip alongside white places it precisely in the color space that wants both passive containment and a punishing edge, payable by either of two colors plus a white pip, which lets it slot into more manabases than a fixed two-color cost would.