Godzilla vs. Megalon
The concept of Hollow Earth presented in the most recent films is a novel one, and a good way to capitalize on that would be to adapt Godzilla vs. Megalon.
The original film’s concept is simple enough: After years of nuclear testing, an ancient civilization akin to Atlantis has had enough of their surface brethren’s destructive tendencies. To that end, they unleash Megalon, an ancient insectoid kaiju who they’ve worshipped as a god for millennia. It then becomes the job of Godzilla – and the newly created Jet Jaguar mecha – to defend humanity from annihilation.
Though it’d be a bit similar to Gigan – both in its design elements and its eventual status as a recurring foe of the King of the Monsters – it’s undeniable that seeing a lizard fight a giant bug monster would be fun.
Plus, the introduction of a civilization still living in the Hollow Earth would help expand the universe’s lore to great effect. They could begin to dig into which monsters still call it home, and set up countless sequels qith the mention of icons that haven’t reached the surface yet.
