Mothra (1961).
A classic monster movie replete with early effects and lots and lots of lovely little models. And a person in a sleeping bag.
We watched the Rifftrax version, which was 1 hour and 32 minutes long. Mothra doesn’t emerge from her cocoon until 1 hour and 15 minutes in. But she is totally adorable when she does.
Also I can’t help but think that if, when the natural world was attacked by humanity, a giant moth that was seemingly immune to all violence directed against it turned up and killed thousands by flying over a city, humanity would stop attacking the natural world pretty damn quick. Mmmm. Excuse me, I need to go sing for Mothra to wake up.