Twilight Sparkle might have made a little bit of an oopsie.
For the record, she did not intend for this to have happened. She was busy checking on the Mirror to the Human Realm and making sure the contraption to keep it open.
She had found an interesting glowing green crystal, and left it in the room. But seems like interacting it with her magic while in proximity to the Mirror might have been a mistake.
Because the thing exploded, and the mirror was now swirling green. And after that, Twilight was getting news from all around Equestria that GHOSTS were appearing.
And not just Pony ghosts, no, there were all kinds of Ghosts. Griffons, Dragons, Hippogriffs, Changelings, Yaks, Kirins and basically every single other creature in Equestria.
The entire Apple Family nearly fainted when Pear Butter and Bright Mac showed up, all ghostly and glowing green eyes and ghostly tail too. Most of them were causing havoc, but Celestia and Luna had managed to talk to some Ghosts more willing to talk.
They apologized for the madness, but after being Dead - being able to come back to the Living, they really wanted to see what they were missing. And well, they didn't blame Twilight either.
But another thing that made Twilight really realize how big of an oopsie she had made, was that the Ghosts are willing to contact The King of Ghosts to come and have a chat with all of the Leaders to apologize for the damages and corral his subjects.
So now Celestia, Luna, Twilight, Cadance and every single other Leader from every other Faction around Equestria are on a round table, awaiting for King Phantom to appear and talk of diplomatic means.
So yes, Twilight might have made a little oopsie.