Ahhh, I see. So in this case, while I know it's possible to obtain this one, I'm unsure if getting this IV spread is possible.
I got this particular Mew in a trade recently (it was likely cloned), and it seems to check out. Though I'd like to get a second opinion on it.
Pokemon Species: Mew
Nickname: ミュウ (Mew in Japanese)
OT Gender: Cannot be determined.
EV's: 6 HP / 252 SpAtk / 252 Speed
IV's: 31/31/31/31/31/31 (Flawless, according to IV judge.)
Characteristic: Takes plenty of siestas.
Moves: Nasty Plot, Psyshock, Aura Sphere, Dark Pulse
Level Caught at: Doesn't say.
Current Level: 100
Location Caught: A fateful encounter seems to have led it across space and time to reach the Kalos region from the Hoenn Region.
Pokeball Caught In: Poké Ball
Any other notes?: None.
I am not positively sure about mew cuaz there are so much hacks that go around with this pokemon I personally don't rng 3rd gen but I know for sure and was told that pokecheck isn't best to look at as well cuaz it kinda stinks at checking 3rd gen mons but the only mew i know that is legal is the eppie mew that is shiny. I just have a feeling it is a hack but dewey may be more help then i am silver do to my lack of the 3rd gen rnging cuaz i had a mew before shiny and it was hacked and looked clean on check.
not sure if you know but 3rd gen checking on pokecheck isn't that good just letting you know so the mew can still come up clean and can be hacked.