I want to do this, so that I can have a different Sprite show up when a "shiny" pokemon appears in the wild/when sending out
Working In RUBY USA
In short, not easily. Pokemon do not have a separate pointer to their sprite in the case that they are shiny, they use the exact same sprite as their regular coloured counter-parts but the pallet is loaded from elsewhere. You would need quite a lot of ASM in order to do what you what.