Do not save the game when you do this=Heres a way to FINDDp box,but you cannot catch it.First,get a Cute pokemon and go into the amity square.Once your in with your pokemon,you "sneak out".At this point,you should be using walk through walls cheat code.Walk out of hearthome and and go in the grass.Youll notice that you will be with the last person you walked with.O_o(maybe marley)run away from that battle,then walk on water.When a pokemon
appears,on the right of it,theres a space but on the left,theres a sparkle
for a shiny pokemon.You'll see a clone of yourself and lots of "dddddddddddddddddddd" and "!!!!!!!!!!!!!!!!!!!!!!!!!!"You cant catch it or fight it because the game thinks it's not there.Youlle see the white box on your clone's team.Use a self move on your self and they boxes would fight each other,using struggle.Then the recoil would hit and they faint.
You can do it over again but if you need to fly you cant because the game thinks someones with you O_O