*wag* *wag* Hehehe, cute! Somepony's happy to nom on his watermelon, ain't ya?
So... "Moon Moon". Unimaginative family, bizarre naming tradition, or a transcript error on his birth certificate? My best guess for his name would be that, being a thestral, his family named him after the moon. Except that the family-name already was "Moon", as in "the Moon-family".
Like Applejack's fully name as part of the "Apple-family" would be "Applejack Apple", then.
Either that or his parents were just being plain silly.
Thank you; The naming of Applejack as "Applejack Apple" is not one of my own design, however, as it is a used in various works of fanfiction. Of which I read lots. No, I'm not aware of a "Moon Moon"-meme.
Hopefully this works. Basically after this post, there was a bunch of posts revolving around wolves looking stupid and doing stupid things, and it became this big joke. (I'm not sure how many sites it was on, I saw it mostly on tickld and on tumblr.)