is a 1975 Japanese kaiju film directed by Ishirō Honda, written by Yukiko Takayama, and produced by Tomoyuki Tanaka and Henry G. Saperstein, with special effects by Teruyoshi Nakano. Distributed by Toho and produced under their effects subsidiary Toho–Eizo, it is the 15th film in the Godzilla franchise, serving as a direct sequel to the 1974 film Godzilla vs. Mechagodzilla and the final entry of the franchise's Shōwa era and the last to be directed by series co-creator Ishirō Honda before his death in 1993. The franchise would be rebooted nine years later with The Return of Godzilla, beginning the franchise's Heisei era.

Plot

Following Mechagodzilla's and the Simeons' defeat by Godzilla and Okinawan guardian monster King Caesar, Interpol agents search for Mechagodzilla's remains at the bottom of the Okinawan Sea in the hopes of gathering information on the Simeons. Their submarine is attacked by a giant marine dinosaur they name Titanosaurus and the crew vanishes.