Okay I got this shiny about a mouth ago and was just a random encounter when I was training my pokémon for the battle tree in Moon, it was my first shiny in Pokémon Moon so I sometimes use it for the battle royal.

And if any of you that are wondering what was the very first shiny pokémon I have come across was a shiny pikachu in my Pokémon X, this was when the games first came out and I've just started my journey, sadly I don't have it anymore because I evolved it into a richu and I accidentally miss tapped and traded it away on wonder trade when I was meant to trade away a zorua I have breeded.