This is Nightmare Moon of "My Little Pony Friendship is Magic, and was a major baddie who reformed. Nightmare Moon tried to celebrate Halloween with the rest of Ponyville, too many ponies in terror from her. She almost returned to her evil ways in frustration. The little ponies finally convinced that they like to be scared by her.
Nightmare Moon is a major antagonist in My Little Pony: Friendship is Magic.
She was the corrupted form of Princess Luna, the younger sister of Princess Celestia who was consumed by her own jealousy toward her older sister. As Nightmare Moon, she acted as Celestia's archenemy until she was restored to her normal form by the Mane Six.
