He’s just one big buoyant boy.
My head canon for sea-based Kaiju is they have a sack of muscles somewhere inside their body that can expand a cavity, kind of like the diaphragm expands the lungs, except instead of taking in air or water it just creates a volume of vacuum inside of them. This makes them extremely bouyant relative to the surrounding sea pressure, so they rapidly ascend and can casually float like a boat near the surface.
But if they ever want to dive again, they just let that cavity collapse and all their bouyancy goes away.
To get unnecessarily scientific here, that wouldn’t change the overall density of the body, no? Even if there’s now a cavity with vacuum, the matter that was occupying that space just moved somewhere else within the volumes of the body and the overall density remained the same.
Now, if it pushed some matter out, air or water, and created a vacuum cavity, that might work. But I’m not an engineer, so correct me if I’m wrong.A hundred ton steel ship floats, a hundred ton steel block does not. Density equals weight per volume. If you increase the volume without increasing the weight, the density will go down.
Exactly my point, the volume doesn’t change in the example provided. Weight and volume stayed the same. We either need to expand Godzilla or it needs to eject some mass.
