Twilight Sparkle trotted on the rugged, abandoned trail that lead to the Castle of Two Sisters. The strange sounds of creatures echoed through the woods, making Twilight trot faster. Then the shade of the trees broke into brilliant light as she reached the bridge. She remembered when Rainbow had fixed the bridge, proving her loyalty to her friends. Smiling at the thought, she cautiously stepped onto the bridge. The bridge swayed, making Twilight step back off. 'C'mon, Twi! Remember theres a whole library on the other side. A library of untouched books. She thought to herself, reminding herself of her purpose. Once again, she stepped onto the rickety bridge. The wood creaked at every hoofstep, moaning under the purple unicorns hooves. After what seemed like an eternity, Twilight reached the other side. Climbing up chipped stone steps, she was in.
Twilight trotted up more stairs, her hoofsteps echoing off the cold stone walls. She trotted down the hall excitedly, hoping to see a library. Creaking open a massive wooden door, Twilight peered into the inky darkness of what she thought was the castle library. Strangely, there were no windows in the room. Lighting up her horn, she stepped inside. The floor of the room had books scattered across it. There were windows, but they were blocked by bookshelves. A picture of Luna and Celestia hung on the wall, though for some reason Celestia was partially scribbled out. 'Weird, Twilight thought to herself. Then she saw a bright light in the corner of the room. Slowly walking over to it, Twilight levitated the object. It was a book, and the image on the cover was glowing. It was a picture of dark crystals, identical to the ones King Sombra used. The title read 'the Art of Dark Magic by Star Swirl the Bearded Twilight smiled. A Star Swirl book? And she hadn't read it?! Just as she started leaving the room it hit her. She couldn't read it. Her mentor, Princess Celestia, forbade it, and for good reason. It was the type of magic King Sombra and Queen Chrysalis used. But it was a Star Swirl book. "Well, I better take it back to the library, so nopony else uses it." She decided aloud, and slipped it into her saddlebags.
Somehow, Twilight felt a little guilty as she trotted home, but she was also giddy from finding such a treasure. Letting out a happy sigh, she opened the door to her home, where she was instantly greeted by Spike. "Twilight! you're home! Did you find anything good?" He asked. "No, nothing that I haven't already seen." Twilight lied. Spike knew she wasn't allowed dark magic, and she knew he would tell the princess if she did. Spike sighed. "Well, that's too bad. Oh yeah! I made dinner! You hungry?" Twilight smiled and nodded. "Yeah, I'll be there in a minuet." She trotted upstairs to her room and tucked the book under the bed.
That night, after a delicious dinner of grass pasta, Twilight snuck down into her basement, book levitating at her side. She quietly tip-hoofed down the stairs and into her lab, where she had cleared an open spot for some spell casting. Taking a deep breath, Twilight opened up to the first spell. 'Conjuring Dark Crystals' Twilight let out a relieved sigh. "See? This cant cause any harm unless I want it to." After quickly reading through the description on the spell, she summoned up a magical aura around her horn. Concentrating hard, she pictured black crystals growing from the ground. That image was the last she saw before she released the spell. A beam of magic, slightly darker than usual, hit the ground. After the spell was finished, Twilight opened her eyes. A small, sharp crystal had sprouted from the stone floor of her basement. "Yes! Yesyesyesyesyes!" she cheered. As small as the crystal was, the spell had worked. The most harm it could cause was a sore hoof. Yawning, Twilight glanced at the clock. "11:46?!" Twilight gasped. She was hardly ever up this late. Being the uptight pony she was, she didn't want to wake up any later than 8:00. Most ponies wouldn't make a big deal out of this, but Twilight, as you could expect, did. Hurrying off to bed, Twilight quickly fell asleep.
Twilight was in a small dark room. Alone. The eerie silence put the unicorn on edge. Suddenly, there as a banging sound. Whirling around, she saw a huge wooden door, barricaded shut. The banging got louder and louder, something trying to get in. She heard the zap of magic, and one of the boards broke. A triumphant laugh sounded from the other side. I almost sounded like Twilight herself...
Twilight woke up in cold sweat. It was early morning, and the sun was barely peaking over the horizon. Twilight took a moment to calm down before looking around her bedroom. Spike was asleep, a Power Ponies comic covering his eyes. Giggling to herself, she got out of bed, almost afraid to go back to sleep. She laughed when she saw her mane. It was a mess! After brushing it out, she looked over to her bed. That was a mess, too. Sighing, she folded the sheets and straightened the blankets.
***Later that day***
Twilight grabbed her book and snuck down into her basement. As long as her friends or Spike didn't come down here, she was good. She would have waited till night, but all the things she could use this magic for made her want to practice. Opening the book once more, she flipped to the second spell. 'Imitation'. After reading through it, Twilight realized this was identical to the spell Queen Chrysalis and the Changelings used. And now that she thought about it, didn't King Sombra use the Dark Crystal spell? Did using these spells make ponies evil? No! Twilight thought. I'm using these spells for good! Looking back to her book, she continued reading. The spell seemed quite simple. All she needed to do was think about the pony she was imitating while casting the spell on herself. So who should she imitate? Spike would be the least suspicious, should she be caught. Concentrating on the image of her assistant, she closed her eyes and set her horn alight.
Twilight almost screamed as a burning sensation overtook her body. Then she burst into green flames, and the burning intensified. Twilight felt herself shrink, and her horn disappeared. Her mane formed four emerald scales. and her tail transformed into a dragons. Spikes popped out of her spine, and claws emerged from her hooves. Scales grew out of her body, replacing her coat. Her ears shaped into the light green fins and she felt her muzzle shrink. Then finally, the green flamed disappeared.
She was on all fours still, but she felt it was more appropriate to stand on two legs. She looked at what would have been her hooves, but they were claws. She looked over to her book and attempted to levitate it over. Then she realized: She didn't have her horn. How was she supposed to turn herself back? Franticly reading through it, she found her solution. 'If you happen to be in the body of a Pegasus, Earth Pony, or other non-magical creature, to return to your body, say Eurt Mrof while concentrating on what you look like.' Relived, Twilight did just that.
The green flames engulfed her once more. She felt the purple scales fall off, revealing her violet coat. Her tail turned back into hair, and her mane grew out of her head as the green scales fell to the ground and were devoured by the flames. Her muzzle grew slightly larger, along with the entirety of her body. Her claws melted into hooves, and her horn sprang out of her forehead. As the burning sensation diminished with the green flames, Twilight was pleased to find herself in her own body again. And just in the nick of time. Spike came rushing down the stairs. "Twilight! Me and Rarity are gonna go- wait, why are your eyes green? They look like mine." Twilight gulped. Her eyes were still Spikes! "Its, um, a side effect. From a spell. Yeah, the, uh, Transfiguration spell, heh." Spike raised an eyebrow, but didn't ask any more questions. "Anyways, me and Rarity are going Gem Hunting. I'll be back in an hour or two." Twilight giggled. "Are you?" Spike blushed slightly. "Okay, you can go." Spike smiled. "Bye Twi! Hope you fix your eyes soon!" Once he was gone, Twilight let out a sigh of relief. He suspected nothing. "Eurt Mrof." She muttered and closed her eyes. Her eyes flashed green and were back to normal.
There was a knock on the door. Twilight rushed upstairs and pulled open the door, expecting there to be pony wanting to check out a book. Instead, there was a tall white alicorn. "P-Princess Celestia?!"
