Crackling Doom

• WWizards of the Coast2014-09-20
  Official Ruling
  Crackling Doom doesn't target any player or creature. For example, a creature with protection from black could be sacrificed.
• WWizards of the Coast2014-09-20
  Official Ruling
  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.
• WWizards of the Coast2014-09-20
  Official Ruling
  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.
• WWizards of the Coast2014-09-20
  Official Ruling
  The sacrifice is not dependent on the damage being dealt. It doesn't matter if that damage is prevented or redirected.

Rulings via Scryfall