Cleansing Beam | Magic: The Gathering
Formats Cleansing Beam is Legal in
Official Oracle Text for Cleansing Beam
Official Rulings for Cleansing Beam
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.