In an alternate timeline, in the season 5 episode of My Little Pony: Friendship Is Magic "The Mane Attraction", as Applejack and the rest of the Mane Six are overseeing the organization of the Helping Hooves Music Festival, Pinkie Pie would still say that she had gotten Equestria's most popular pop star, Countess Coloratura, to perform for it, with Applejack questioning who she is like normal. However, this time, as Applejack tells Pinkie to wait for Rara to arrive, with the latter replying that she doesn't have to as she believes that Rara's arrived, everypony hears hard rock music playing in the background, and a black tour van with blue flame art painted on it, and to everyone's surprise and confusion, it isn't Countess Coloratura that's arrived: it's actually the hard rocking Ember Mclain (who in this world is in the form of a unicorn pony, or should I say, unicorn ghost pony, to have her better fit into the MLP FiM universe) instead.
Ember explains to the Mane Six that Countess Coloratura had an incident with some of her fans during one of her concerts, and because of that, she unfortunately couldn't arrive for the Helping Hooves Music Festival, but she'll be happy to take her place to perform for it, as she's just as big of a star as her, with the Mane Six and everypony working on the festival's preparations accepting this, and being excited for it.
However, in the back of her mind, Ember, showing a wicked smirk on her face, happily says to herself that her plan has gone without a hitch, as with the "countess" out of the way, she can take her place in the festival to make everypony in Equestria remember her name so she can gain enough power to overthrow the 4 alicorn princesses of Equestria, and take over the land for herself, and rule it with an iron hoof, as we cut to a flashback with Ember kidnapping Rara and Svengallop before they could head to the festival, and imprisoning them in an underground cave, like how Queen Chrysalis did it to Princess Cadence in "A Canterlot Wedding", and now that she's here, she can take Equestria for herself, and eventually goes on stage to rehearse her song "You Will Remember", and Ember tells herself that she can't let her cover be blown as to not get caught in her plans for conquering Equestria, and to play it cool and act like a normal unicorn pony, and not show off her ghost powers (not yet, at least), so they can come into fruition beforehand.
How does Ember taking Countess Coloratura's place in "The Mane Attraction" and being the villain of the alternate version of it change the events of the original episode? How would it affect the events of "The Cutie Re-Mark" if Ember had become a big enough threat to both Equestria and Starlight Glimmer's revenge on Twilight for taking her village from here back in "The Cutie Map", and going back in time to stop Rainbow Dash's sonic rainboom to prevent the Mane Six's cutie mark bond from being formed, leading to an unlikely alliance between Starlight and heroes as Ember is standing in the way of Starlight's plans? Could the Mane Six save Rara and Svengallop, and stop Ember from taking over Equestria? How would they be able to deal with a ghost pony like her since they've never faced something like her before? How does such a scenario play out, and why is that?