Rulings

• 2017-08-25
  If Territorial Hellkite didn't attack during your last combat, most likely because it was tapped or you didn't control it at that time, then any opponent can be chosen at random.
• 2017-08-25
  If a player can't be attacked, that player can still be chosen at random.
• 2017-08-25
  Territorial Hellkite must attack the chosen player if able, not a planeswalker that player controls.
• 2017-08-25
  Players may cast spells and activate abilities after a player is chosen at random for Territorial Hellkite but before it attacks that player.
• 2017-08-25
  If Territorial Hellkite can't attack the chosen player, it's free to attack any other player or planeswalker or to not attack. If there's a cost associated with attacking the chosen player, it's free to attack any other player or planeswalker or to not attack. But if there's a cost associated with Territorial Hellkite attacking at all, Territorial Hellkite has to attack the chosen player or not attack.