Yes, just arms&feet of Legendary Trio. Trio of over-billion years old dragon-like gods. Some kind of union, peace and solidarity sign. Inspired by numerous fanarts on Japanese Creation Trio fans from Twitter. Hope you can view Giratina's claws enough under Palkia's arm and Dialga's foot (Giratina is the biggest, so it is why its claws are the lowest).
Anyway, in our lore, these 3 were always friendly to each other (almost sisters). Also hope that Giratina's gold essense looks consistent between Dialga's and Palkia's (though its homeworld is more complicated, its Power source orb is golden).

Dialga, Palkia and Giratina belong to GameFreak
NOTE: This art won't appear on DeviantART.