User blog comment:Ghido/The Minya Theory/@comment-11836-20140414191259

I have a theory too. Well, it's not MY theory, but it's one I find plausible.

You may notice that in Son of Godzilla, the egg Minilla was in was cracked by the Kamacuras. It's possible that because they cracked the egg before it hatched normally, it stunted Minilla's growth. Sure, he grew a tad, but he eventually got stuck in his usual appearance thanks to those Kamacuras.