ChoiceColor choice = new ChoiceColor();
controller.choose(outcome, choice, game);
if (choice.getColor() != null) {
final int damage = source.getManaCostsToPay().getX();
FilterPermanent filter = new FilterCreaturePermanent();
filter.add(new ColorPredicate(choice.getColor()));
for (Permanent permanent:game.getBattlefield().getActivePermanents(filter, source.getControllerId(), id, game)) {
permanent.damage(damage, source.getSourceId(), game, false, true);
}
return true;
}