The Phantom from 10,000 Leagues

The Phantom from 10,000 Leagues is a 1955 sff/horror film starring Cathy Downs and Kent Taylor.

via Youtube:

1000 Misspent Hours:

Not content to create one of the least impressive monster movies of the 1950’s, screenwriter Lou Rusoff and director Dan Milner (who also co-produced The Phantom from 10,000 Leagues with his brother, Jack) went the extra mile to deliver simultaneously one of the decade’s least impressive spy flicks.

Moria says

Even as cheap 1950s monster movies go, The Phantom from 10,000 Leagues is rather dull.

DVDTalk calls it "a grindingly unimaginative hackwork job that shows its monster but probably shouldn't have bothered."