in pokemon uranium (fan game) there is a legendary pokemon called the sakimater (or somthing like that) that is actually a evolution of the three main bugs of the reigon. So i have a feeling those tiny green things may be a pre evo to zygarde. but thats just my theory. and if you're one of those people who thought that green blob was a mini duskul, no... its a baby larvitar...
those pics pikachu of the giant zygarde remind me of diglett. you cant see the bottom...
MOD EDIT: Please do not double post.
Well as pointed out before its not unheard of for a Legendary to breed and produce a "prevo", but the example of this (Manaphy and Phione) doesn't have the prevo able to evolve (and its in all the IV games). Hmm, I don't know if this has been brought up, but maybe the way for Zygarde to Mega Evolve you need to have the LGG in your party. GF seems to be experimenting with having ways for Pokemon to Mega Evolve, Mega Rayquaza does so by needing to know a certain move. What if Zygarde does this but instead of it being restricted in some way its the trainer?
And the reason the giant one is missing its bottom is probably because the only image of the Giant Silhouette is also missing its bottom as its a shot of its upper body.
I actually realized something, since we've had all the "Primal Reversion" talk in ORAS...Could the big guy be Zygarde's answer to that? I personally think that the new game will be "Pokemon Zeta" ("Z" motif of Zygarde and the Greek letter bit from ORAS) and this is (obv) the version mascot. I mean hey, we've already said it's Yggdrasil...
And if it is Yggdrasil...could the LGG be the "seed" of the tree? (since there doesn't appear to be an Ymir counterpart...)
I think it'll just be called Z, why give it a Greek letter now when X and Y were just a single letter? They get fancy with the Z or maybe add another thing to it (like maybe 2Z, since visually 2 and Z look alike (as the Porygon family had pointed out previously), 2 references its a sequel/updated version and Z since its about Zygarde, and 2Z could also mean "two Z-named Pokemon" as in Zygarde and the LGG who, if its related to Zygarde, would probably have a name that starts with Z). However eitherway the Z will be by itself since XY were by themselves.
And good idea with LGG maybe being based on a seed/sprout! Though I don't know what Ymir has to do with it, from what I could find he has nothing to do with Yggdrasil.