Discord had an idea. After carving Fluttershy's face into rocks had gotten boring, he got a master plan, a plan to keep him occupied for hundreds of years. Fluttershy's face would be carved into the moon so large that ponies from Equestria could see it, and so detailed that a telescope could see every contour just as it had been in Fluttershy's life. Discord remembered her with that much detail. Discord began his project, carving it out one claw at a time.
Twilight frowned. She thought she saw an unusually dark dot on the moon, but it was probably just her imagination. She hoped it was, if the moon was being destroyed by chaos it would mean that Discord had failed. No matter how much Twilight hoped Discord would reform, she didn't really believe he could do it. She went to bed, exhausted from her daily struggles in keeping Equestria together.
Discord continued his project, scratching the rock one inch at a time. For years, he scratched out his pattern, imagining the result in his mind. He would finish this by himself, the only important thing he'd ever done without magic.
After centuries of work, Twilight stared up at the moon and recognized the image on the moon. It was Fluttershy's face! Tears of joy and sadness glistened on her face as she smiled up at the celestial object. Fluttershy would be remembered, she would never be forgotten. Discord was still keeping his promise.
"I hope you succeed, Discord." she smiled. "Fluttershy would be proud of you."
Discord heaved a sigh. After a thousand years, he was finished. Fluttershy would be remembered forever. He felt a wave of euphoria wash over him, and wondered.
If this is how great it feels to do something with your own limbs, instead of resorting to magic, what else have I been missing?
Another thought came to him.
If I hadn't followed along with the silly plan to reform me for a little while, I would never have discovered friendship. If I had never learned about friendship, I'd still be stuck in stone with nothing to do for all of eternity. I haven't done anything useful with my powers of chaos in my entire life. This is the first useful thing I've done in my entire life, millennia of living and the only useful thing I've done is create a single monument?
Suddenly, it hit him, and he spoke out loud to himself.
"I hearby swear to never use my powers of chaos again to do anything that I could do by my own efforts, and to do my best to make up for the millennia of time I wasted."
He knew now he was ready. With a snap of his fingers, the world shifted, and he appeared in Equestria once more.