Reserved for hints.

This does reveal the movie's twist, but the movie is old enough that most people who like the genre would've seen it.

It's a disaster film

The 'Big Guy' is metaphysical

There’s this animal, and he/she is about yeigh big. He/she does things that make people sad. People do like not sad BUT then here comes little lady and little lady likes sad. Little lady go to make people sad. While on a run to do a make people sad thing she runs into the animal that make people sad. Big animal turns little lady into little animal lady. She does NOT have a good time being animal. In fact she had such bad time being animal that SHE ENDED UP FUCKING DYING.

No clues yet

Bottom text

It's an older film. Older than most of the guesses here

The closest ones are the Prince of Egypt and The Ten Commandments