Why you may ask well a certain game called pokemon omegaruby and alphashapphire released giving primal reversion form to Groundon and kyogre before them primal dialga existed it would be nice to see this in game and there are many different photos you can alter to create the sprite . https://www.bing.com/images/search?q=Primal+Dialga&view=detailv2&&id=10082CAF8A91642C6DD34114E31FF3B38D0DCBA0&selectedIndex=6&ccid=iQ%2BmTrgw&simid=607996602117194297&thid=OIP.M890fa64eb830e3616e061e18abbcac60H0&ajaxhist=0