recently my friend traded over the GTS for a shiney and we were curious if there was any way to test it's authenticity...anyone know?

What level is it?
What are its stats?
Where is the location it was met in, etc.
Questions like that will help us answer.

However, without even knowing, I'm going to take a guess that it was indeed hacked due to the fact that it's very strange that someone would want to give up a shiny pokemon on the GTS.

lvl 36

atk 73, def 69, spec atk 86, spec def 68, speed 99

timid nature

egg was hatched in veilstone, april 21 2008

it's also already immune to pokerus

need anything else?

There's no sure fire way to know whether or not it's hacked because of the fact that it was hatched instead of caught. It levelling and stats look normal paired with the nature.

Being immune to pokerus seems suspicious, but that could just be from your party.

i see, even if it is hacked though...does that restrict the pokemon in any ways? like will some games not read it or ANYTHING? basically, will the fact that it's hacked hold my friend back from using it on a team? (i realize it has a bad nature and stats for this but he's thick and just goes "OMG BLACK " lol

It looks pretty legit to me. I was just thinking that if it was met on January 0, 2000, or it was met in a "fateful encounter" or something like that, then that would definitely show that it was hacked. It's still very odd that someone just gave up their shiny on the GTS though.

It was probably a clone or they were GTS fishing.

This helps to know if it's legit, or you could find someone to use a program to check it.

If it says no possibilities, it's hacked. :)