Cosmos's Servant

Shining Armor, Cadence, Rarity and Discord traveled to the Canterlot Castle via teleportation from Discord's magic.
Then, they saw Celestia, Luna, Big Macintosh, Zecora and Twilight standing in front of them with pink eyes and cat-like slits. Twilight was in the center, while Celestia and Luna stood on her right and Zecora and Big Mac were on her left. She was wearing a black hued cape, with black evening gloves that reached under her armpits, and black thigh highs that reached on top of her flank. She worn a long black choker on her neck. She was wearing a black corset and black panties with a pink bow on the front. And she wearing gray slippers on her backhooves. She worn her golden tiara. Spike came walking from behind Twilight's left side with Flurry Heart.

"I see you have accepted my terms, right?" Possessed Twilight said as she pulled her left hoof up on her chin.

"Yes," Shining Armor said with disgust.

"I have decided to be the one you will control and free your body," Cadence said as she raised her right hoof up on her chest.

"Actually, Spike already nominated somepony for me. And that somepony, is Rarity," Cosmos Twilight said as she suddenly pulled Rarity up into the with her magic.

"What?! Spikey Wikey how could you?!" Rarity shouted in disbelief.

"You're the reason why Twilight's under Cosmos's complete and utter control in the first place, Rarity!"

"What?" She said as she still floats in the air.

Cosmos walked up to Rarity. "You see Rarity, it's all thanks to you. It's your fault that I possessed your friend and made her my servant. Not to mention, it's all your fault for giving a piece of my mind to Twilight. It's also your fault for making me use her to do all sorts of terrible things," Cosmos Twilight said.

"But what about Flurry Heart?" Cadence questioned her possessed sister.

"That was all part of Spike's plan to make you come here. And once this spell is finished, I promised your Great and Honourable, Spike, the Brave and the Glorious, that I will give him back his sister unharmed. Now, let the spell... Commence!" Cosmos Twilight said as she snapped the bracelet onto Rarity's neck.

Spike walked over to Shining Armor and Cadence. "Sorry guys, I just wanted my sister back," he said as he looked down to his right in shame.

Cadence used her magic to levitate her baby into a hug, followed up with Shining Armor looking at Spike. "It's alright, Spike. We would've done the same thing to get Twily back," Shining said.

Then, Spike, Shining Armor, Cadence, Flurry Heart, and Discord stared looking at the ponies. Twilight stood in the middle while everypony else surrounded her and lifted their heads up. A pink beam of magic was flowing from their horns and chests and fell down into Twilight's body. Which then, their sister/aunt/friend started glowing pink pink for a little. Thus, turning her fur red as her mane remained the same. Twilight started growing bigger, her hooves turning into talons, her wings becoming bat-like, her horn retreating into her forehead as two horns appeared on the back of her skull. Her tail grew longer, her neck growing cobra flaps, her muzzle becoming more menacing, her teeth sharpening into fangs while all her clothes ripped right off. And what stood at the same spot that was once Twilight was now a female red draconequus. Her head was a goat, but the back of her head was like a cobra. It was Cosmos, and she started laughing maniacally. Then, she stopped and used her right talon to pull what seemed like a kangaroo pouch. Then. She put her left talon in there and searched for the pony that she promised to return. Then, she lifted her arm out with an unconscious Twilight in her grasp, wearing the same clothing that she was wearing before completing the spell.