Magical Mystery Cure

Magical Mystery Cure is an upcoming episode of the third season of My Little Pony Friendship is Magic. It is scheduled to air as the thirteenth and final episode of the third season, and the sixty-fifth episode overall. The title of the episode alludes to Magical Mystery Tour by the Beatles. Meghan McCarthy confirmed that the season finale is going be a 3-parter.

Production and development
Show storyboard artist Sabrina Alberghetti helped with some clean up on the episode, and said in late December 2012 that she used "what little power" she has to throw in one of her favorite background ponies, who she specified is not hers.

In the summer, musician Andrew Stein played mandolin for show musician William Anderson on a short cue for an episode of the third season;   Stein wrote in early November 2012 that "Apparently it's in the season finale this year" and that it "almost didn't happen" as it was "extremely lucky" that their schedules coincided for it. In early August 2012, Anderson wrote that "thirteen already exists" and quoted a subsequent response "You could also interpret him as saying that 313 has already been completed, probably ahead of some of the others, but since I'm just some random nobody, I'd have no idea why they would do that" with his own response "You don't?"

On February 9, 2013, the episode was shown early at an official Hub event in Los Angeles.

Summary
"In the special coronation episode 'Magical Mystery Cure,' Twilight Sparkle accidentally casts a spell that switches the Cutie Marks and destinies of all her friends, and the only way she can reverse the spell is by writing her own magic. Little does she know that by achieving this great accomplishment, she will fulfill her destiny and emerge a princess."

Princess Celestia sings one of the songs in the episode.