"If you hadn't been able to get the candy back to everypony it belonged to," she said, "What were you planning on doing? That was an awful lot of candy--- and an awful lot of ponies."
Nyx rubbed her head and thought it over. "I hadn't really thought about it," she admitted. "I suppose maybe I would've left it in little bags on everypony's doorsteps? Or.... I dunno." She was suddenly curious. "What were YOU going to do with it all?"
"How do you know I wasn't going to eat it all?" Celestia teased.
"Oh come on," Nyx said scornfully. " You'd've had a bellyache for WEEKS!"
"Is that experience talking?"
"That's the other reason I didn't just keep all the candy," Nyx admitted meekly. "I tried to eat a whole tray of candy apples all by myself once. Mom made them for a party and left them on the counter and I just couldn't stop..." she cringed at the memory. "I barfed all over the place...."
Celestia lost altitude again.
"You and Luna have a lot in common," Celestia said, wiping tears of laughter from her eyes. "Her first Nightmare Night, she did take all the candy back. We didn't have so many sweets back a thousand years ago, nor in so many kinds. I tried to warn her," she sighed, "But she sat up all day gobbling candy. Oh, she was so sick the next night.... The moon was green for three nights in a row." Nyx squealed with laughter. "The night after that, the Foals' Hospital in Canterlot received a VERY large, anonymous donation of candy for the colts and fillies. There were a lot of happy children that night." She sighed again. "Almost made it worth the tummyache."
http://www.fimfiction.net/story/30242/14/nightmare-night-and-nyx/chapter-14