Nightmare Moon is a character from the animated series My Little Pony: Friendship Is Magic. She represents the dark side of Princess Luna, who was once the princess of the night. Consumed by jealousy and a desire for power, Nightmare Moon was banished to the moon for a thousand years. Her return threatens to plunge the world into eternal night. When she reappears, Nightmare Moon seeks to cover Equestria in darkness, challenging the Mane Six to stop her. Ultimately, the power of friendship helps to redeem Luna, transforming Nightmare Moon back into the beloved princess, restoring balance to the land.