Radiance — Choose a color. Target creature and each other creature that shares a color with it gain protection from the chosen color until end of turn.
10/1/2005 The color you choose as the spell resolves has nothing to do with the color or colors shared by the affected creatures.
10/1/2005 All creatures that share a color are affected, even your own.
10/1/2005 A creature “shares a color” with any creature that is at least one of its colors. For example, a green-white creature shares a color with creatures that are green, white, green-white, red-white, black-green, and so on.
10/1/2005 If it targets a colorless creature, it doesn’t affect any other creatures. A colorless creature shares a color with nothing, not even other colorless creatures.
10/1/2005 You check which creatures share a color with the target when the spell resolves.
10/1/2005 Only one creature is targeted. If that creature leaves the battlefield or otherwise becomes an illegal target, the entire spell is countered. No other creatures are affected.