Today, a new trailer for Pokemon Sun and Moon debuted on YouTube featuring the Pokemon Zygarde in its 10% and 100% forms. Zygarde was a Ground/Dragon legendary Pokemon from the games Pokemon X and Y, but the Zygarde that appears in those games is in fact only at 50% of its full potential.
In the trailer, we see the 10% form, which takes the form of a green and black dog with a leash. It has two unique attacks: Thousand Arrows, and Thousand Waves. The second form, called 100% or perfect form is hard to describe with words, it's like a giant with 2 long....shoulder flaps? He really does not resemble anything recognizable. The Perfect form does come with its own unique attack, Core Enforcer, which fires a beam into the ground and draws a Z. We don't know what any of these attacks do, so one can only speculate.
What's interesting is that between these two forms, there was a transformation sequence. This implies that going from 10%, to 50% and 100% will have some in battle mechanic, similar to something like Mega Evolution.
I'm rather surprised that these Zygarde forms are appearing in Sun and Moon and not a potential "Pokemon Z" This concept was introduced some months ago, and it's been a core plot line for the Pokemon XYZ Anime, however, it never made an appearance in the X and Y games themselves. Perhaps this was more of a limitation of the X and Y engine, or perhaps they didn't want to introduce 3 new bizarre evolution mechanics all at once (Mega Evolution, Primal Reversion, and this Zygarde Evolution). Another interesting question is, how will Zygarde play into the story of Sun and Moon? Will he be plot relevant or just another optional Legendary Pokemon like he was in X and Y. Regardless it's making Sun and Moon out to be really interesting games already.