A fateful encounter seems to have led it across space and time to reach you from the Hoenn region.
Mitsuki is a twitch streamer that gives custom Pokemon in community service but wonder trade is open 24/7. this stream gives out shiny mythical Pokemon and even zeraora but shiny locked Pokemon used to be shiny but it isnt anymore. yes your shiny deoxys is hacked since what are the odds of getting hundreds of thousands of shiny deoxys from ruby or sapphire or emerald? and even if he did get it legit, how did he manage to fit every single one of them in a poke ball, they were all perfect nature, and the birth island ticket event is over so it is 100% hacked.