Ok now this cheat is tricky but IT IS POSSIBLE I DONE IT. ok what u do is go find kyogre or groundon by talking to the guy who gave u castform. or find rayquaza. or any other high lvl or anceint hard to catch pokemon. then what u do is throw a ultra ball at them with or without full hp. and as soon as the pokeball closes press and hold a,b,l, and r at the same time.