Exorcist

White's hyper-narrow specialist against Black, built when Magic enforced the color pie as much through dedicated hate cards as through what each color could cast. Against a Black deck, this Cleric is a repeatable removal engine for two mana a shot; against anything else, it is a 1/1 with an activated ability that has no legal target, which on the board is functionally a do-nothing body that still costs you a card. The design logic is pure flavor-driven asymmetry: the holy man repels the unholy and is helpless against everything else, so the card swings from inert to backbreaking based entirely on whether the opponent showed up in the right color. That kind of color-targeted hoser was a standard tool of early design, a way to hand each color a structural edge in mirror-of-opposites confrontations without granting generically useful removal. The friction that kept it from being oppressive even in its one matchup is the tap-gating: a one-target-per-turn effect rather than a sweeper, so the Black player can race the clock or simply present more threats than a single Exorcist can answer in a turn cycle. Modern design distributes its hate across sideboard slots and conditional triggers, smoothing out the variance so a card is rarely both unplayable and game-winning depending on the opening hand. This is the older, blunter instrument: a creature that refuses to participate in any game that is not the one it was printed to win.