If you bring your Origin Forme Giratina into your team, then use the "Move item" function on the PC box, it's stats won't be recalculated.
Then you can level it up, and it'll have very weird stat changes.
I did that, and my Giratina had:
HP: +4
Attack: +-15
Defense: +23
Sp. Atk: +-17
Sp. Def: +21
Speed: +2
Then you can level it up, and it'll have very weird stat changes.
I did that, and my Giratina had:
HP: +4
Attack: +-15
Defense: +23
Sp. Atk: +-17
Sp. Def: +21
Speed: +2