The Hallows Galla is an event hosted by Princess Luna / Nightmare Moon on the last full week of October. People from all over the multiverse get to come and dress however they want, whether it's impersonating someone or it's nothing on. Parties, ballrooms, multiculturalism, suspense, or even the architecture of the palace, just to name a few examples.
This is a fan-made Found-Footage/epistolary crossover series that explains the mysterious Hallows Galla, hosted by Nightmare Moon / Princess Luna once a year, and how things worked. However, something happened one year, but what? This story is mostly explained in slideshows and text as we find out what happened in the ruins before, during, and years after the incident. The crossover includes The Loud House, My Little Pony, The Casagrandes, Pokemon, Transformers, Zelda, Disney, Mickey Mouse, Bluey, Equestria Girls, Tell Your Tale, and so on.