Helm of Shadows
The Helm of Shadows was a mysterious object worn by Nightmare Moon.
History
The Helm of Shadows was presumably created by the Pony of Shadows of the corrupted universe, as he effectively created both Nightmare Moon and Daybreaker. However, in some sources, Nightmare Moon was instead created by a dark presence from the Moon or some other alien presence. Whatever the case, when Princess Luna fell to the darkness, she adorned her helmet.