New Enemies / Ideas for enemies

[~Rogue~ 193]

Hey guys. I don't know where this is supposed to be so for now I'm putting it here. What do you guys think would be a good enemy? Or even use an old enemy for a new episode. Here's mine.

 

Twilight gets an unexpected delivery from someone (They deliver knock on the door than run away). A spell book that has some spells that twilight has never seen before. Twilight looks through the spell and gets curious about them. She tries one that is *suggested* to try. Nothing really happens. The day Goes through normally and she goes to sleep. She wakes up in an unknown place and feels a little weird. She decides to go outside. She's in some sort of city. She then asks the townspeople where she is but they just ignore her. She goes inside worried and looks in a mirror. To her amazement she's trixie! She must find her way to ponyville, convince her friends that she swapped bodies with trixie, defeat trixie (whom is in twilights body), and use the spell. In the end trixie explains everything like how now everypony hates her and apologizes. They forgive her and trixie tries to become mane six's friend. As a comedic thing I think that twilight should talk like trixie (since she is in her bodie) and she can't help but call herself the great and powerful twilight! What do you guys think?