I may have a possible hacked Pokémon I got from trade, what should I do?

I got a Shiny Groudon from trade AND it was not my fault. I am scared I think it's hacked and what if the Pokémon company finds out and banishes me?

I don't have game sync yet if that matters

Reasons why I think it's hacked:

1. It's shiny and I think I read something somewhere on another site that game mascot lengendaries were shiny locked.
2. It doesn't have that black cross thing near the shape things like all my other pokemons do.
3. When I read where it was from it said something about it coming from Johto region.

Is it hacked? What should I do?

Solution 1:

First of all, if you don't use that Pokemon for online competitions you have nothing to fear.

1. Groudon is shiny locked only on ORAS, it could be legit if it comes from RSE or SS.

2. The black cross icon only means that the Pokemon is born or obtained in Alola, it doesn't mean that the Pokemon is hacked or something like that.

3. If it comes from Johto it could be legit, because you can catch a Groudon at Embedded Tower.

If you don't want to have an hacked Pokemon just release it or trade it, it won't corrupt your game and you won't get banned only for that.