Princess Luna stretched her wings. She let out a yawn, proceeded down the hallway towards her room, and opened the door. With her horn aglow, Princess Luna raised the moon.
"How long will you keep up your act, Discord?" She said to the marble statue in her room. "I never commissioned the artists to sculpt a piece of your likeness."
"You're no fun." Discord said. A top hat materialized on his head. He took the hat off, reached inside, and, after a polite nod to Princess Luna, pulled a jar out of it. Inside the jar, a viscous black substance slinked around. Each time the creature hit the crystal clear glass side, it received a small zap of magical energy that lit up the room. "Frisky little critter."
Princess Luna sighed. She levitated the container from Discord and opened a sealed door in her room. An ethereal realm came into view. Stars lit up. Granite pedestals rose from the floor. The container's glass reflected Princess Luna's stern gaze. "To think this vile thing caused a subject of this kingdom so much misery. If I had only found it sooner. If I only found him sooner. How difficult was your mission?"
"You're all such a fascinating lot. One of Princess bookworm's tomes told me they had been eradicated long ago. When you sent me on this little mission, lu lu, I was rather intrigued. What intrigued me most of all was the target of this creature." Discord said. His jovial demeanor changed. Discord's gaze focused on the container Princess Luna levitated in front of her. The creature inside swirled about, ramming into the container. Each successive hit caused a more powerful magical jolt to come. It succumbed to the magic, the black goo stopping its actions. "To give you the full report," Discord materialized a stack of papers while putting on a pair of reading glasses, "it would have been... 'difficult' to remove this thing if it had gone on for too much longer."
Princess Luna bit down on her lip. She glared at the container. "Dreamasites, I thought I had eradicated their kind from Equestria."
As she placed the jar on the pedestal, a thick magical aura surrounded it. Several symbols embedded themselves into the container.
Princess Luna faced Discord, her gaze melancholic. Discord snapped his claw, the papers disappearing along with his reading glasses. He looked at the regal mare, and then the container. "You really know how to kill a mood, Luna. You know, I may be evil, well I 'might' have been evil, but what this Dreamasite did... even I find it cruel. It's hard to believe that little donkey went for so long without dreaming of a single happy moment. Ugg, Fluttershy is wearing off on me!"
"Those infected by these creatures have their dreams and happiness siphoned away. In the end, all that remains is a shell of what one once was in this world. You are right though. His mind is still young, and it will recover. Still, I do not know the extent of the damage. It may be irreparable." Princess Luna said. She nodded to Discord, "Please give Fluttershy my thanks. I knew it was a citizen in Ponyville, yet I didn't --"
"Listen well Princess Luna, " Discord said in a stern voice before he exhaled a heavy sigh, "this will be one of the rare occasions I will ask for something. Watch over 'him' tonight. Also, I know you will discover what I've done. Don't tell Princess Bookworm what I gave that little donkey. That's a mystery Soapbox needs to unlock on his own and share at 'his' discretion."
Princess Luna chuckled at Discord before he floated off, the draconequus chewing on a cup of mouthwash. She looked at the container in front of her; an aura of magical energy radiated from it. As she left the room, sealing the vault behind her, Princess Luna smiled. "Sir Discord, I promise he will have pleasant dreams from now on. Though he is quite stubborn, from what you've told me, I believe this Soapbox will be a powerful ally."