The darkness stirred. It sensed a disturbance heading its way.
It gritted its mental teeth. It was still laying siege to the redoubt that Twilight Sparkle had constructed, and could not spare much of its attention. It sent a thought-probe, confirming what it already suspected: The conciousnesses of Twilight's friends were coming into Twilight's mind.
It diverted a small portion of its energy. In its current situation, it could not prevent them access - but it could influence where they landed. It split them up, scattering them about Twilight's brain. It then left a small part of its power to slow them down.
Satisfied, it turned the majority of its focus back to the siege. Although there were no weaknesses as of yet, it could sense that Twilight's strength was ebbing.
It would have complete control soon, and then it would destroy Equestria.
Rainbow Dash sat up with a groan. Her head felt like a freight train had run over it. She shook her head, looking around.
"Where am I?"
"That's a good question", she heard in response to her question. She whipped her head around.
She saw a cyan pegasus walking towards her. Something seemed familiar about her...
Rainbow Dash gasped. "You're the Equestrian Rainbow Dash!"
"Correct. Although I am wondering why my other self doesn't have wings. I know that you guys all walk on two legs, but why don't you fly?" she replied.
Human Rainbow Dash sighed. "Magic isn't really present in our world - or, at least, it wasn't until recently", she corrected herself. Only then did she realize something. "Hang on a second. Why am I still human?"
Her pony counterpart rolled her eyes. "We're inside Twilight's mind. Your conciousness manifests itself in the way that you see yourself. You've always seen yourself as human, so you appear as a human."
Human Dash looked at Equestrian Dash. "How do you know all this?"
Equestrian Rainbow rolled her eyes again. "Princess Celestia lectured us all on this. I was incredibly bored, but she said that all this info was vital to the mission, and that all of us needed to know it. I tried to get out of it, but she wound up performing some magic knowledge transfusion spell that implanted the knowledge into my brain."
Human Rainbow mused on this for a second. "Why are we inside Twilight's mind, anyway?"
Her Equestrian counterpart sighed. "It's a bit complicated..."
Pinkie Pie awakened rapidly.
As in 0 to 2000 mph rapidly. One second she was solidly asleep; the next, she was on her feet, surveying the area.
A second later, a pink pony bounced into view.
No words needed to be said. The Pinkie Sense on both was in an overdrive mode that didn't normally exist, somehow copying all the knowledge and memories that were related to the current situation from each Pinkie to the other.
Human Pinkie Pie spoke first. "Can you get out some cupcakes?"
"Sure thing, me!" her Equestrian counterpart replied, warping reality and causing two dozen cupcakes to appear in front of both of them.
They plowed into the cupcakes, both in silent agreement that, as soon as they finished, they would look for the others and free Equestrian Twilight Sparkle from the evil inside her mind, no matter what.
Twilight Sparkle stood, streching her back. She looked around, seeing that she appeared to be in a large cavern filled with crystals that crackled with purple energy.
"Where am I?"
"I quite frankly don't know", a voice from behind her stated. Twilight turned around.
"Sunset Shimmer? You're here too?" she queried of the...thing that had replied.
"Indeed I am", the thing replied, as it coalesced into a human girl with flaming orange and red hair.
"What were you there?" Twilight asked.
Sunset Shimmer sighed. "I'm not sure why it happened, but I was flickering between my pony and human forms."
Twilight shook her head. "Well, regardless of what happened there, we need to find out where we are."
A new voice answered. "We're inside Twilight's mind."
Sunset and Twilight turned. A small purple and green creature that looked for all the world like Twilight's dog Spike - if something that had claws, scaly skin, and a bipedal gate could look like a dog - walked forward. It bowed. "Spike, at your service."
Twilight stared. "Are you the Equestrian version of my dog Spike? And what do you mean that we are within my mind?"
"The answer to the first question is yes, but no, we are not within your mind, Human Twilight. We are within Equestrian Twilight's mind", the little purple dragon replied.
Sunset Shimmer stepped forward. "Can you tell us why the princesses have sent us here?" she asked.
Spike sighed. "It's a bit of a long story..."