This is a fun little idea I had when I thought about doing something with Princess Luna, since I haven't done one with her yet. Then I came up with this and having Fluttershy in the mix.

It's another typical night at Ponyville. Everypony was asleep and Luna was in the dream world, watching over all the ponies. But Luna finds Fluttershy's dream and sees her underwater. Luna thought Fluttershy was drowning and sees it as a nightmare. So she enters Fluttershy's dream and finds that she ends up holding her breath, despite being inside another dream. Luna grabs Fluttershy and is about to pull her out, but Fluttershy quickly stopped her.

"Luna, What are you doing?," Flutttershy asked, with bubbles coming from her mouth.

Luna creates a bubble around her head so as not to lose any air. "I thought you were drowning and I wanted to save you."

"But this is what my dream is. Swimming underwater and maybe living in it," Fluttershy said. Bubbles once again coming from her mouth.

"Oh," Luna replied, "I'm sorry. I wasn't thinking. Can you accept my apology? I promise I won't do that again."

"Apology accepted," said Fluttershy.

Luna smiled. She popped the bubble around her head and gave her a big hug. "Thank you Fluttershy!," she said as bubbles came from her mouth. Luna continues to hold on to Fluttershy as the two drifted around in the water. Until Luna realizes she has work to do and removes Fluttershy from her grasp.

And as Luna left, Fluttershy woke up. She felt confused as she looks around. "Somehow that dream felt real," Fluttershy quietly spoke. She didn't want to wake any of the animals that are sleeping in her cottage. And after another look around, she went back to sleep, dreaming of being underwater again.

(Yeah, I know Luna doesn't go to sleep at night, but it looked like a cute image in my mind.)

Originally drawn in pencil. Colors, filters, shading, bubbles, Cutie Marks, background, and edits done in Photoshop.