Is there any method I can use to work out if a Pokemon is hacked or not?
Because I just got a shiny Silvally over the GTS for a pretty run of the mill Pheromosa and I'm just wondering if its legit or not. I'm not really bothered it just seems like an unfair trade since they'd have had to SR to get a shiny Type: Null (unless they got lucky and got one right a way) right?
The only way to tell if something is hacked is if something is illegal about it. So if it's not in a ball it can be, has moves/Ability it can't(Or shouldn't currently) have, stats aren't possible, location not possible, level not possible, whatever else I may be missing. The games themselves(For online features) simply check the stuff I mentioned, if anything is not currently possible than I'm pretty sure you get locked out from online features for a certain period of time. But even if a Pokemon is hacked, if it's done in a way that everything about it is legal than the games wont be able to tell.
So if the Type: Null happens to be a Shiny, level 100, perfect IV, EV trained, Pokerus inflicted, good Nature Pokemon, then...it likely is hacked but there is no way the games would be able to tell since nothing about it is impossible in the games.
On the other side, if it's under level 40, in anything other than a Pokeball, and has a met location other than Aether Paradise(Pretty sure it should be this) then it was hacked and the game will know if you use it online.