If you loved Creature from the Black Lagoon, try This Island Earth
A bridge between a film you've already seen and one most people haven't. This Island Earth has roughly 3.6× fewer votes than Creature from the Black Lagoon — it's a deeper cut, not a mainstream recommendation. Here's what they share, and what the second one does that the first one doesn't.
What they share
Both films are directed by Jack Arnold, and they sit in Adventure / Horror / Science Fiction territory. If that's the register that drew you to Creature from the Black Lagoon, the second film will land in a comparable space — through a different lens.
What This Island Earth is
High desert, late night. A humming capacitor. Two scientists whisked across space to aid aliens in a brutal war. Their benefactors offer advanced technology, but hide a grim secret. A sterling example of widescreen 1950s science fiction.

