You can't ask for hacked pokemon here. I can't blame you since it's not on the hacked pokemon list.(COUGHCOUGHTwilightBladeCOUGHCOUGH)
All Toys R Us (MYSTRY) Mews are set to be non-shiny. If you want a little proof, heres a thread that got locked from offering it >
Right here.
actually, it is, it says on the list that all shiny mystery mew, from the toys r us event are hacked
Oh, and btw, thanks for the shiny mewtwo johnny