Godzilla vs. Red Moon (1971) unmade kaiju film

story/plot
"A strange new kaiju emerges from the moon's surface and quickly flies down to Earth. Upon reaching its destination, the creature is sighted and dubbed Red Moon. Almost simultaneously, another kaiju appears on the nearby Habu Island, located in a part of the Ryukku Island Chain within the Okinawa prefecture. This new monster is then dubbed Erabus.

The Japanese Self Defense Force comes to the conclusion that the two monsters should be led to one another in the hopes that they will kill each other. The plan to lead the two to one another is a success; however, instead of fighting, the two monsters mate, and it's revealed that Erabus and Red Moon are a female and male, respectively, of the same species. Erabus then gives birth to Halfun. With the situation only getting worse, the JSDF is scrambling to create a new strategy to deal with the kaiju. Things go from bad to worse when Halfun is kidnapped by an entrepreneur. Shortly after getting kidnapped, Halfun dies during the moving process. With their child dead, Red Moon and Erabus go berserk and start rampaging the once peaceful Okinawa. Having sensed the two from the beginning, Godzilla finally arrives and does battle with the two kaiju, emerging victorious and bringing peace back to Okinawa"