(1965) Frankenstein Conquers the World: Baragon was a dinosaur who burrowed underground to escape the extinction of the other dinosaurs and other prehistoric creatures died out. He adapted to and lived successfully. But when the sounds of a nearby factory disturbed and awakened Baragon, he emerged from the underground and attacked it. He appeared later at Shirane and destroyed the village. Then he emerged at a farm, where he ate the livestock - with feathers flying out of his mouth. During these attacks, Baragon was not seen, so the mutant human Frankenstein was blamed. But there was a person who survived the destruction of the factory who claimed there was a second monster that had attacked the factory. When a small group of scientists searched for Frankenstein, an explosive awoke Baragon from his sleep. He emerged to attack the scientists, but Frankenstein appeared to protect them from Baragon. The two fought a climactic battle, but Frankenstein ultimately defeated Baragon by choking him and breaking his neck. But in the end, a fissure appeared beneath the two and swallowed them up into the Earth
(1968) Destroy All Monsters: Baragon is seen as one of several monsters kept in captivity on Monster Island. Along with the rest of Earth's monsters, he is brought under the control of an alien race called the Kilaaks during their invasion of Earth and forced to destroy cities in their cause. It is unknown if this was the same Baragon that battled Frankenstein or another. The latter theory is supported by the fact this Baragon was smaller than the original. The 1965 version of Baragon stands 25 meters (82 feet) in height, the 1968 version stands up to 57 meters (or 190 ft) in height. He later breaks free from this mind control, and watches (but does not actually take part in) the fight against the Kilaaks and their remaining monster, King Ghidorah before returning to Monster Island with the other Earth monsters.
Of all the monsters in the Toho fame, the Baragon suit was borrowed and used the most by Tsuburaya Productions, the company made famous for its work on the TV show Ultraman. The Baragon suit was reused several times to create the monsters in the series: Neronga, Gabora, and Magular, as well as Pagos from Ultra Q. Notably, Haruo Nakajima (the Godzilla suit actor as well as suit actor for Baragon in his initial debut) also played the suit actor for these monsters (with the exception of Magular.)
In Destroy All Monsters, Baragon was supposed to attack Paris for the film, using his burrowing ability to smash the Arc de Triomphe from below. Unfortunately, the Baragon suit was unavailable due to the fact it was on loan for work on Ultraman. Baragon was replaced with Gorosaurus for this scene, but was still blamed for the attack. Gorosaurus was also given Baragon's special burrowing ability and even his signature roar to further confuse viewers. Baragon was also supposed to be used as a guard for the Kilaak base, but he was not shown on screen while doing this, possibly for the same reason above. Baragon's other appearance was supposed to be Godzilla vs Mechagodzilla. He was supposed to fight Mechagodzilla in the scene after he smashed that building, but instead they replaced him with Anguirus.
In the Millennium series, Baragon reappeared in the 2001 film, Godzilla, Mothra and King Ghidorah: Giant Monsters All-Out Attack as one of three ancient guardian monsters. The other two are Mothra and King Ghidorah (originally Varan and Anguirus). When Godzilla is revived by the souls of the people who died in World War II, Baragon, Mothra, and King Ghidorah were summoned to protect the nation from the threat. Baragon was the first of the three guardians to confront Godzilla and was eventually killed by the monster's atomic breath. Baragon does not have a heat ray or a glowing horn, but he still has his burrowing and extraordinary jumping abilities.
In Godzilla Final Wars, Stock footage of Baragon from Frankenstein Conquers the World was seen during the opening claiming that Baragon was one of many monsters that arose due to the devastation that the World Wars brought, along with Varan, Gezora, Gaira, Titanosaurus, and Megaguirus.
Frankenstein Conquers the World
Destroy All Monsters
Godzilla, Mothra and King Ghidorah: Giant Monsters All-Out Attack
Godzilla: Final Wars