>>40215433He also said it's within the Pokemon. He didn't have a specific answer to where inside it the Pokemon was but he did clarify it's inside.
Also it's the building energy that causes Dynamaxing itself. We knew this from e3. In the gym you have to build and gather energy, in the wild however this energy naturally exists in pockets that the wild Raid Battle Pokemon use. This was ALSO explained during e3. The only thing that's changed is it's not a physical biological growth and it's now an ultraman-esque transformation which actually fits very well aesthetically with the Dynamax's red energy glow.
I don't need to have a head canon because all this shit was already presented to us and no one realized how shit was. Ohmori wouldn't have to pull it out if his ass either because, again, it changes fucking NOTHING about Dynamaxing other than a small lore detail. They're still giant monsters kaiju forms the only difference is they're concentrated energy.