my guy, im glad someone asked!! I actually have some sort of a story on my mind, I might actually make something out of it or just leave it as a silly idea, who knows. but I can tell you that not the mane six is to stop the spirit. and how did she got possessed? simple, childish naivety and an attempt to show yourself, filly visited the everfree forest in order to prove her fearlessness and end with the bullying from tiara and spoon, but ended up getting too deep into the forest, disturbing the peace of the spirit, succumbing to its beliefs, and losing control of her own mind and body, well, partly. as I said, maybe someday this will be something more than an idea. and again, thank you!