I have to rewatch, because I could very well be making this up subconciously, lmao.

But I do recall it being said that he was quite young and still growing.

Even if that's not the case, I'm good with just rolling with a growth spurt. It's the least fantastical notion of any of the three movies that preceded it, so I'm good with it.

Far as the axe, I've heard a good theory:

Everything we're seeing is confined to the first half of the film. At some point, Kong rips off one of GZ's fins, and somehow makes the axe from that.

I loved the axe too.

Kong with a weapon? An axe at that? Sign me up.

If I'd have seen that on paper, I'd have been all in.