I AM SO IN LOVE WITH THIS PART! 
Storyline: Twilight over exerted herself trying to defeat Trixe which killed her. Trixie looks back and feels bad as her Twilight's friends mourn the loss. Trixie finally goes crazy and has to leave Ponyville and her past behind...again.

My Little Pony Friendship is Magic is owned by Hasbro and Lauren Faust
I only own the video!