Well, if you ask me, I'd say this.
The pokedex entries for p/d/p are:
It is said to have emerged from an egg in a place where there was nothing, then shaped the world. -This tells us nothing, so let's move on to Pearl.
It is told in mythology that this Pokemon was born before the universe even existed. -Again, nothing, so, let's move on to the final entry, Diamond.
It is described in mythology as the Pokemon that shaped the universe with its 1,000 arms. -DING DING DING!!! Folks, we have a winner! 1,000 arms! Let's take a look a sprite:
http://www.pokemon.marriland.com/platinum/pokedex/Arceus/
Yup, the ring can extend into 1,000 arms. Much like the mock groudon in Jirachi wish maker.
-just my opinion