I used it once on my snivy and well here is what happened:
it turnned shiny but it's gender changed (it was a girl then turnned male)
IT got pokerus but it went away when I went to the pokemon center
Then right next to the hp numbers it said ?56/?56
then when i got to battle it was level 226
So i got mad and restarted the game
Is there a better code we can use? Because I really want a shiny starter