o_0 Umbreon pwns this game. Here's the deal, for the past few days,..

Question for Pokemon Ruby

o_0 Umbreon pwns this game.

Here's the deal, for the past few days, I have been using my long-lost Gameshark (Not GSSP) to get Mew, Mewtwo, Hitmonchan, etc. For my Ruby version. Now that I have had all Johto and Kanto Pokemon, I was wondering how the codes work for Hoenn Pokemon. I recently put in a code for Deoxys (all 6 lines of it) and found a female Missing No. in the grass at level 0. Feeling sure it would turn into Dexoys, I put it in a Master Ball and named it Mystery. My party was full, so I went to look at it in my PC, only to see that it was still a Missing No. Bewildered, I clicked on "Summary", only to find the screen turn completely black. Hard-resetting on the game, I find myself in front of the PC, just like I was before I checked on Mystery. The weird thing though, was that I never saved in this location! I looked back in my PC, only to see that Mystery pulled a houdini. I went outside the Poke Center to go look for another one. Using Sweet Scent in some grass to allure the Pokemon, the game crashed yet again. After trying again (not using Sweet Scent) I got the same results. I tried in caves, forests, surfing, but Ruby always crashed. So I instead put in the Latias code, but the same thing happened, so whenever I touched the tall grass the game froze. Can someone tell me what I'm doing wrong?