_{spoiler warning for the special event but y'all should have watched Celine's stream by now}

This cutscene. Oh boy, this cutscene.
First, let's set the stage, shall we?

The Sinjoh Ruins are canonically located "somewhere between Sinnoh and Johto" which is an awful lot of information alright. It's said that the ruins were built by the two different groups of people from both regions hundreds of years ago, and Cynthia comments on the architecture showing signs of both cultures. This may be quite reflective of the real world inspiration, not only in the context of representing the collision of Japan's current primary ethnic population and the Ainu, a group indigenous to Hokkaido as is it today, but also to the much older context of Japan's ethnic prehistory being shaped by both mainland groups from the Korean peninsula populating the south and Okhotsk peoples from the islands in the north. The Mystri Stage (real on the nose there, Cynthia) is easily compared to an artistic-religious trend so ubiquitous in the cultures of our world that I could talk about it for the rest of my life and get nowhere meaningful, but I'll draw particular attention to the Christian symbol of the Shield of the Trinity as well as the Mandala of Buddhist and Shinto traditions. In this case, we have a geometric system that represents the Creation Trio specifically with Arceus at its centre.

Arceus takes position zero, the Unown appear, time and space get a bit funky, and then shit gets weird.

First, light. A brilliant flash in the darkness. Not only is this iconic of many creation myths ^{(Let There Be Light!)} it may also be a deliberate parallel to the Big Bang. An infinite point in an infinite void. The light shines from the darkness, expands and contracts, waxes and wanes. Arceus appears as if from nothing, as its legend claims it came to be before all else in the universe. As the thunder of creation booms all around, we see Arceus' eye fade to images of the cosmos. The Horsehead Nebula. The Helix Nebula. The Orion Nebula.
Then we see a new pattern emerging. From the singular ring of light at the centre, we see the geometry of Arceus itself expanding and unfolding into view. There's something distinctly reminiscent of the trinary geometry we saw in the Mystri Stage before, and yet more than that, a resemblance to a pentacle or magical circle, warding runes, even a vague hint of Dante's Paradiso in the circles-within-circles that ecompass our Almighty Creator.
Arceus appears within the strange geometry, our fixed point in space and time, the focus of everything. Images of our real world, of the natural world, of trees and seas and clouds. Then the creations of mankind. The technology of civilization. The new world we have created atop the old.
Then images of great natural forces, destructive and transformative powers, volcanoes and hurricanes and lightning and high seas. The elements unleashed before us in turmoil, vast in their power and untamed in their raw beauty. We have conquered this world and built our works upon it and yet it stands still unfathomable about us, ever beyond our understanding or our power to control.
Then we see a field of stars, and then a bizarre and tiny, almost microscopic glimpse of some unknown thing. From the Sun to the cells in our blood. A juxtaposition of the grand scale of the cosmos and the infinitessimal complexity of life within it.
We see the face of our Creator. We see its Creation in an entire galaxy. The Earth itself. Our entire existence confined down to this solitary insignificant planet. Superimposed upon by the sacred geometry of creation, the shape of god, it becomes an Egg.
Just as Arceus was born itself from the egg of creation, so has Arceus created the Earth, the cradle of its own creation. Our egg. Our cradle. And now, a Pokémon's egg.

The Egg stirs.

Where did Arceus come from? What made it? What begat it? Was there anything before Arceus? Will there ever be anything after Arceus? Is this whole universe nothing more than a dream of a sleeping god? These are questions the series has occasionally glanced toward, made vague suggestions about, hinted at, but will never truly address. Nor will we ever have any real answers.

Perhaps some things are better off left Unknown after all.