Enchant creature
Enchanted creature has double strike as long as it’s an enchantment. Otherwise, prevent all damage that would be dealt by enchanted creature. (A creature with double strike deals both first-strike and regular combat damage.)
Armament of Nyx continuously checks to see whether the creature it's enchanting is an enchantment or not. If the creature isn't an enchantment and becomes one, or it is an enchantment and stops being one, the effect will change.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.