Evaporate

Color hosers from this era punished a creature for what color it was, not for any functional property it carried, and few cards preserve that vanished design philosophy as purely as this one. The premise is targeted punishment by hue: white and blue creatures take a point, everything else stays untouched. The detail that dates it is the resolution check on color itself. The spell reads the colors a creature actually has on the battlefield when it resolves, so a creature recolored by another effect is caught or spared accordingly, and aiming a sweeper at two specific colors of the pie rather than at a keyword, a type, or a triggered ability has aged out of the vocabulary entirely. One point of damage for is a low ceiling even against the ideal board, and a sorcery that does nothing to red, green, black, or colorless creatures is about as narrow as a sweeper gets. The "and/or" wording is the only generous note: it hits a mixed white-and-blue board and a mono-blue board with the same line of text, sparing the designer a second printing. What survives is a snapshot of how color hosers were once priced and scoped, back when a dedicated answer aimed at two colors was considered a fair thing to put on a sorcery.