1)Get a pokemon that knows DEFOG
2)Go to Victory Road
3)Go in the door on the right of the inside of Victory Road
4)Use DEFOG
5)Talk to the fancy dressed Lady and talk to her (she is like the girl with green hair in Eterna Forest)
6)Use walking cheat so she is not with you
7)Go outside on other side of wall
8)Go on the water untill you find a pokemon
9)It will be you and you VS _____ pokemon and some weird pokemon. You will have your pokemon and the other you will have the same weird pokemon
10)Try it