Varan The Unbelievable (1962)

Starring Myron Healey, Tsuruko Kobayashi, Clifford Kawada, Derick Shimatsu, Kozo Nomura
Directed by Jerry A. Baerwitz & Ishiro Honda
(actor & director credits courtesy IMDB.com)

A scientific experiment on a small village's lake accidentally stirs a giant creature sleeping on the bottom, that sets off to destroy everything in its path.

This American version of Daikaiju Baran, per Wikipedia, changes a good deal of the story and instead fashions a different narrative with American Healey in the lead, using limited footage from the Japanese film, including almost none of the principal stars.  Healey's a favorite actor of mine, a talent at projecting a good-natured swagger in many of his roles, and he's likable in this as a military scientist with a loving Japanese wife, but the American crew who recut the film don't pay much respect to the work of Japanese director Honda and his crew, letting their scenes dominate their version.  What does remain is some impressive footage of the monster, with spikes all over its reptilian exterior and a fearsome countenance.  I've read some accounts this was perhaps a too familiar return by Honda to Godzilla-like territory, and it is without doubt similarly structured from what I could tell from the footage used, but I still found it unique in its own way and look forward to seeking out the Japanese version.