This collaboration between Tsuburaya Productions — the makers of Ultraman, whose close ties to Toho provided them with directors and costumes — and Toho was released to Japanese theaters on December 17, 1972. It was originally going to be a Godzilla film entitled Godzilla vs. Redmoon, which would have celebrated Tsuburaya Productions’ tenth anniversary and the character that started it all — Godzilla.
The film would have Redmoon — who arrived from the moon — and Erabus — arriving from Habu Island — being guided together by the Japanese Self Defense Forces to attack and eliminate one another, but instead hooking up and giving birth to a new kaiju named Hafun. However, a carny entrepreneur would exploit and ultimately kill the child, leading both creatures to go wild until stopped by Godzilla.
Instead, we got this.
Daigoro became an orphan after the military destroyed his mother and the one soldier who stood up to the order has adopted the kaiju as his own child. In order to pay for his huge food bills, he’s had to start a business all around the monster, so you can see some hints of the canceled film in the final product.
Meanwhile, another kaiju named Goliath has come to Earth and Daigoro decides to prove himself by battling the monster. Since many of the folks in his hometown didn’t trust Daigoro, they had been feeding him an anti-growth drug that makes him too weak to defeat Goliath.
He nearly dies but recovers and trains hard every single day, coming back to save humanity, who strap Goliath on a rocket and send him into space.
Daigoro is made up of parts from Red King, one of Ultraman’s best-known foes and he has a roar that would later be used for Godzilla Jr. in Godzilla vs. Space Godzilla. As for Goliath, he was made from the canceled Redmoon costume. He has Astromons’ roar.
While a more child-friendly kaiju movie, it’s still a blast.
You can watch this on YouTube.