Reigon: Devil of the Seabed (海底の魔王レイゴン, Kaitei no maō Reigon?) is an unmade 1966 Nikkatsu film.
History
Reigon was the fourth and final unmade film in a series of concepts Nikkatsu Company had before making Gappa.[1][2] Reigon got the furthest into the development out of the four scrapped projects, receiving a plot synopsis, speculative screenplay, and kaiju ideas. Planning was done by Hideo Kodama, the draft was written by Shun'ichi Yukimuro and Ryuzo Nakanishi.
Plot
A giant manta ray dubbed "Reigon" appears one day and wreaks havoc across the world--and then fights a giant iguana.