This move effect may be in need of research. Reason:Does it check the Pokémon's species before or after using Transform (in each generation)? You can discuss this on the talk page.
Unaffected by item negating effects (such as Embargo and Klutz). Item manipulating effects (such as Trick and Fling) cannot give Giratina a Griseous Orb or remove a Griseous Orb from Giratina.
Generation IX
The Griseous Orb is now affected by item manipulating and negating effects due to no longer causing Giratina to change form.
In Pokémon Platinum and HeartGold and SoulSilver, only Giratina can hold a Griseous Orb, and Pokémon holding a Griseous Orb cannot be traded. From Generation V onward, these restrictions no longer apply.