In an attempt to make the top of this post as spoiler free as possible, I'm going to drop most of this below the break.
If you have watched the season 4 animatics from Comic Con, you probably already know what I'm talking about! Continue below.
Alright spoiler lovers, I'd like to see some theories on what you all think is actually going on with everyones favorite moonpony. Some of the few I've seen floating around the last few days:
Timetravel/History Exploration - I personally don't see this one working, as Luna directly references Twilight Sparkle's newfound princessyness. There have been quite a few hints throughout the end of Season 3 of Luna's displeasure at the idea of Twilight ascending.
Alternate Universe - Twilight Sparkle visits an alternate universe with a Luna that never fully recovered from the corruption of Nightmare Moon. Another one I'm not too keen on, but only time will tell!
Shes EVIL - It's hard to imagine Luna going back to the dark side, especially if the comics are part of the pony canon. It's even more hard to believe she has a grudge against Twilight. The two of them seemed to get along pretty well during Nightmare Night.
There are a million others. What do you all think? Hit the comments up with your theorycrafting!