Pearl Shard

The activation reads as a single colorless cost or a discounted white one, and that fork is the whole design idea, predating the hybrid mana symbols later sets standardized. The " or " clause gives a colorless artifact a color identity without locking out the decks artifacts are meant to serve: a white shell gets a cheaper, repeatable damage-prevention valve, while everyone else pays full freight for the same insurance. It belongs to a cycle of Shard pieces that each guarded a different color's signature effect, with damage prevention drawn as white's. The effect itself stays deliberately small: two damage, prevented, to any target, which makes it as useful for shrinking an attacker or blunting a burn spell as for keeping the player alive. Because the cost per activation runs high and the ability repeats, the card behaves less like a one-shot prevention spell (the kind that stops a single attack and then disappears) and more like a standing tax on incoming damage, available turn after turn at a price that never lets it fully wall off a swing. That is the tension it resolves: how to let an artifact care about a color without requiring it. The answer was to make white a discount rather than a gate, and to keep the prevented amount modest enough that the repeatability is the appeal, not the rate.