Godhunter Octopus

• WWizards of the Coast2014-04-26
  Official Ruling
  Whether the defending player controls an enchantment or enchanted permanent is checked only as attackers are declared. Once Godhunter Octopus has been declared as an attacker, it will continue to attack even if the defending player loses control of each enchantment or enchanted permanent they controlled.

Rulings via Scryfall