Doesn't King Sombra technically already do that with his doorway that leads to and shows you your worst fear?
Surely, that Chinese curiosity shop must still have a lot of items left to make the lives of our ponies more interesting...
Since the last villain had only three actual lines of "dialogue", I would expect Gordon Freeman to be the next on the list.
Bad idea. She will turn into a fanon Celestia such as Molestia. Well now that I think about it... Might not be a bad idea...
I happen to like Molestia. That blog is hilarious. However, I seriously doubt that will we ever see her on FiM, considering the fact that the writers wish to remain employed.
What? Why would that eeeeeeever cause drama? *cough* Also, calling it now: [video=youtube;7CnOysetlQw]http://www.youtube.com/watch?v=7CnOysetlQw[/video]