2019-08-23 : If there’s no creature you can legally attach Gift of Doom to as you turn it face up, or if you choose not to attach it to a creature, it’s put into its owner’s graveyard.

2019-08-23 : No player may take any actions between the time you announce that you’re turning Gift of Doom face up and the time it’s attached to the chosen creature.

2019-08-23 : This doesn’t target the creature Gift of Doom will enchant, so an opponent’s creature with hexproof or a creature with shroud may be chosen this way. The chosen recipient must be able to legally be enchanted by the Aura, so a creature with protection from black can’t be chosen this way.

2019-08-23 : You can’t pay Gift of Doom’s morph cost more than once.