Based off of Moonie shorts [Filly Nightmare Moon], Chapter 95 Fate Conspires.
After watching the events of an alternate timeline where an adult Nightmare Moon was taking care of a child Anon, they get curious as to how that situation actually came to be. They watch and see how the alternate version of themselves first met. This also gets Trixie a bit curious as to how the version of them she knows met, and points out that they had promised to tell the story some time. And it seems this is that time.
As Trixie was about to throw Anon and Moonie out of her wagon, Anon convinces her to let them stay be agreeing to tell her the story. Though it's not much different from what she had seen in the alternate timeline, The story of how they met was still touching to her.
This is essentially my version of how the events in that alternate timeline would have happened in this timeline. Functionally, this acts as Chapter 95.5
I waited a long time when I got to that chapter of the original story to read this spin-off. And I was very disappointed with this story. This is literally a copy of the recited chapter, with reversed names. When you see that something is literally copying the original source, it becomes boring to read because you already essentially know everything in advance. In the end, it was possible at least to insert lines where Anon suggests that Mooney is the daughter of Princess Luna due to their obvious similarities, or it was possible to reveal their relationship a little more, but this was not done.
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I could try to defend my position. But in reality, my position is that you're right. I admit that it is just a copy. It was just for fun. If you don't like it, then don't worry, it's not canon. In fact, I think the original story already did a proper origin story at this point if I'm not mistaken.