Crackling Doom deals 2 damage to each opponent. Each opponent sacrifices a creature with the greatest power among creatures that player controls.
9/20/2014 If a player controls two or more creatures tied for the greatest power among creatures they control, that player chooses one of them to sacrifice.
9/20/2014 The sacrifice is not dependent on the damage being dealt. It doesn’t matter if that damage is prevented or redirected.
9/20/2014 Crackling Doom doesn’t target any player or creature. For example, a creature with protection from black could be sacrificed.
9/20/2014 In a multiplayer game, each opponent, starting with the active player and proceeding in turn order, chooses which creature they will sacrifice and then all creatures are sacrificed at the same time. Each successive player will know what the players before them chose to sacrifice.