Perhaps nuking Godzilla caused some of his cells to break off and become mutated by the radiation to such a degree that, left unchecked for thousands of years, an entire Godzilla-spawned ecosystem has popped up as a result? "Monster Planet" indeed!
There's also that new picture there of flying Servum posted along with that description:
Certainly looks very metallic and also weed-like, which would kinda fit if these things are just all over the place now.
Whatever the case, they certainly seem to be taking things in a totally new direction with this, which I really like. I feel like this is the kind of thing we should have gotten during the Millennium series (though I doubt they'd have had the budget to make this exact film in live-action), just individual entries going off on crazy tangents and showing us takes on Godzilla we've never seen before.
"Absorb what is useful, discard what is not, add what is uniquely your own"
- Bruce Lee