[quote name='MaximuM_MayheM']The only way is to buy a cartridge that has Mew pre-loaded on it. Thats how I had to get mine.
Unfortunately, it is already in my Pearl game, and I don't believe there is a way to clone pokemon in DP yet.
Also, on how to spot fake pokemon, here are some ways
1) If it is shiny, be skeptical
2) Check where it was caught and at what level. If, say, you have a Kyogre caught at level 5 in Littleroot town, it's hacked.
3) This one is harder to check, but check IV levels. You can go here:
http://www.serebii.net/games/iv-calcdp.shtml to check. IV's range from 0 to 31, 31 being the best. Most hacked pokemon will have perfect IV's in all six stats, and keep this in mind, the chance of catching a pokemon with perfect IV's in the wild is 1 in
1,073,741,824. You'd have a better chance of having all your pokemon catching pokerus on their own then getting a single perfect IV pokemon.
4) If it is an evolution or legendary that is below what you find it at or before the level it evolves, it's probably fake (like a level 1 Garchomp).
EDIT: About my metagross, if I used the right berries (Pomeg,Kelpsy,Qualot,Hondew,Grepa), it is still showing now 4 stats as perfect (one went down). Did I use the right berries?[/QUOTE]
For every berry, 10ev pts go down in one stat. So to be sure, you need 26 berries of each kind of stat to reduce them all to zero. And getting that many will take ages without AR. Now if all the stats aren't maxxed, i.e. can't add any more evs and they are as high as possible, you'll have to do this. And what do you mean by perfect? If more than one stat is perfect (I mean full evs and a helping nature), then it's hacked.
Also, all those things you were listing can be directly altered via pokesav, so the most you can do is be skeptical. Unless you run into an idiot breaking one or more of those restrictions, then it's blatantly hacked.