Barbarian
The old moon (the moon we had before the current moon) was actually just a huge barbarian floating in the sky.
Just imagine a huge barbarian (whatever that means to you) floating in the sky, looking down. Some ancient people look up and wave at the old moon barbarian.
こ, う, ご
なんぞ
きゅう
At least, this is the kind of story you told your 子 (こ) when they asked you where the moon came from.
"You see, my child, the old moon was not like the current moon. It was a giant barbarian in the sky, who would eat children that asked too many questions."