>>58394464
Yeah I was gonna say it's a lot like the Megalith from the Kalos anime (creatively translated as 'Giant Rock'). An artficial Zygarde made by Lysandre from what was basically an enormous mega stone, and it was powered by an empowered Pokemon at its core (a Chespin which accidentally absorbed primal energy), which ultimately ends up getting blown away by Perfect Zygarde.

In the case of ZA we have another artificial creature made in the past by AZ this time, powered by Eternal Floette when it absorbs her energy, and which gets beaten down by Mega Zygarde. It's pretty much the same kind of thing.