Godzilla and Friends Marathon: 10 of 46
Atragon, aka Kaitei Gunkan (The Undersea Warship), is yet another sci-fi/adventure from Toho that features an external threat to Earth's population, except this time the threat is not from outer space but, instead, from the undersea Mu Empire. There's also a brief kaiju appearance from the sea dragon Manda, who will go on to appear in multiple Godzilla films.
The story revolves around the development of the secret undersea battleship Atragon, aka the Gōten (Roaring Heaven), which will also return in other films. As the Mu Empire prepare to conquer Earth, Mu agents are sent to find the location of Makoto Jinguji, a WWII Captain thought to be deceased, who has been secretly developing the Gōten.
This was another enjoyable sci-fi/adventure that's worth watching for Eiji Tsuburaya's special effects work. It was unfortunate that Manda didn't get to do much, but seeing the Gōten in action was quite fun.