Skreee!
"Twi?" Rainbow Dash asked slowly. "What was that?"
Twilight's mind sputtered. What kind of creature makes such a noise? She thought to herself, flipping through her extensive knowledge to find nothing reasonable. Aside from one thing. "It might be a changeling." Twilight said hopefully. "A solitary locust." Rainbow Dash nodded, and together they slowly turned around, to see some horrid monstrosity clawing it's way out of the ground.
The creature could best be summarized as some sort of nightmarish binding of a squid and an ape. But that would be a grave understatement. The creature's body was that of some hairless, atrophied ape. Ribs stuck out, giving it a skeletal look. At the shoulder, instead of two arms, there were four, each one providing it another chance at pulling itself from the ground. The neck was atrophied like the body, and the muscles and veins bulged under the waxy, discolored skin, which ranged from white to deep purple in coloration.
But the head could have very well caused anypony to turn tail and run. The head was shaped like a dome, off centered from the neck, giving the tapering head a beak-like look. But other than that, there were no other discernable features. No nose, nor mouth. Neither eyes, nor ears, or even hair for that matter. Only the waxy, white skin stretched over the dome.
As it found more purchase, it was able to pull it's lower half from the ground, revealing a mass of tentacles, as if a young tree had just been ripped from the ground. They all flailed in the sunlight, grasping everything within reach to help pull it further from the ground. It scrabbled towards the unconscious form of Trixie, using it's arms as well as tentacles to pull itself closer. But Twilight was faster, and encased it in an orb of psychic energy.
It crawled about the bubble, screeching and slamming into the bubble, trying to flail its way out. The repeated needs to focus were leaving Twilight feeling drained, and this thing wasn't helping either. It slammed into the bubble again, shattering it like the changeling army did. It turned and scrambled for one of the tables in a nearby coffee shop. Once it reached the shade of the umbrella, Twilight had an idea. She encased it again, and this time it seemed content to rest for a moment.
"Rainbow Dash, go get Spike. I need to speak with the princess immediately." Twilight commanded, to which Dash saluted and flew off. Twilight gingerly stepped up to the dome, in an attempt to speak with it. "Hello?" She asked. The thing turned its dome towards her, sending a shiver down her spine. "Who are you?" She asked, and the thing pulled closer to the bubble, and reached it's arm towards her, before it was knocked back by the shield. It let out a shrill of pain, and Twilight toned the shield down a bit, to prevent harm.
"Hello?" She asked again, and it repeated the previous action, reaching out with its arm, only to be shocked again. This time, it let out a shrill of anger, and slammed into the shield, which shimmered under the pressure. It raised it's hands, and turned towards Trixie. It hit the barrier again, and a small portion fizzled away. It reached out again, trying to grab her, but she was out of it's reach. It let out another angry shrill, and slammed into the barrier again, crumbling it like before.
It crawled forth again, trying desperately to grab her, only for her to be whisked away by Twilight's magic. It took the change in stride, pivoting on a single arm so as to face her new location. Twilight pulled Trixie closer as it raced forwards, and when it was within reach, she quickly teleported to the other side of the clearing. It let out a low growl, and turned around to face them. It lumbered forward again, charging across the street, where Twilight was able to trap it again.
It wailed about, slamming into many things, as if any amount of intelligence had escaped it started "hunting" them. It was just so primal... Fluttershy. Twilight realized. She could probably calm this thing down. She looked to the sky, relieved to see Spike and Rainbow Dash flying in. "I came as fast as I could. What did you need us to do?" Rainbow asked, Spike sliding off of her back.
Twilight smiled, and relaxed a bit. "It's good to see you. I'm pretty exhausted from today. Dash, I think I have a solution to resolve this peacefully. Can you get Fluttershy and the biggest cage you can find?" Twilight asked, some of her words laced with the heavy tones of exhaustion. Rainbow Dash nodded, then took off, flying as fast as she could, not out of fear like before, but worry that her friend wouldn't be able to last much longer.
"Well, what can I do, Twilight?" Spike asked, shaking slightly.
Twilight looked down at him with a reassuring smile. "I need you," She said, ruffling his spines lightly. "To write a letter to the princess." He smiled, nodded, and pulled out a piece of parchment and quill. "Dear princess Celestia. I found something that I feel has great importance. I would like to see you in pony to discuss it. Please hurry, as I may not be able to hold it for long. Your faithful student, Twilight Sparkle." Spike finished scribbling on the page, before rolling it up and breathing dragonflame across it, burning it away, the ashes flying off into the distance. "Thank you, Spike." Twilight said, yawning.
"Sure thing, Twilight." Spike responded, with a thumbs up.
Twilight blinked, and turned back to their captive, who seemed unusually still. It simply sat there, leaning forward on all four arms, its back heaving slightly, as if it were slowly breathing. In and out, in and out. It's asleep! Twilight realized. She let out a sigh, relaxing slightly. A short while later, Twilight could see the two pegasai carrying a cage plenty large enough for the creature, Fluttershy with a look of concern on her face.
"What poor creature needs me, Twilight?" She asked as they pulled in for a landing. "And why did we need such a large cage. Twilight pointed at it, and when Fluttershy saw it, she dashed underneath a nearby table, cowering. "W-wh-what is that?" She asked, stammering slightly.
Twilight sighed. "I have no idea. It was acting very... primal, and so I thought you might be able to help. As for the cage," She added, pointing to the bubble, "Holding up a shield for so long, along with a little 'friendly competition' I had, is surprisingly draining." To add effect, her horn sparked slightly.
Feeling comfortable the thing was asleep, Twilight lowered the shield, then lifted it softly on a small patch of telekinesis. She floated it into the cage, where it rested on the hard, solid bottom of the cage. Twilight quickly shut the cage door, locked it, and breathed out a sigh of relief. "There." She said, before promptly collapsing to the ground, fast asleep.