Sea Baragon appears to be a fusion of the two Toho kaiju, Baragon and Maguma, with a large, narwhal-like horn extending out from the center of its forehead along with slanted walrus-like tusks. Sea Baragon lacks the large, floppy crescent-shaped ears of his earthly counterpart, and also has a slightly stubbier face. It has no special attacks or beam weapons, and relies entirely on melee moves that involve its horn. From his illustrations in the manga, he appears to have areas of lighter skin. Similar to a shark in real life, this may be so that Sea Baragon's back is camouflaged into the ocean's colors, and so he is harder to see from above, whereas his belly blends in to the sun's rays entering the water, in a technique called Countershading.
In 1992, Baragon was revived after his fight with the Frankenstein's monster, by the mad scientist Oniyama, who revived several other monsters, with Baragon being the most heavily modified. Using the DNA of Narwhals and Walruses, Baragon now became Sea Baragon, and resided in waters of Izu Oshima. Like all of the revived monsters, Sea Baragon was sent to fight Godzilla as the beast marched its way to the heart of Tokyo. The two exchanged blows back and forth, until Sea Baragon managed to gore Godzilla's chest with his horn. Godzilla, in a fit of rage, broke off the beast's horn and disintegrated it with his atomic breath.
- Due to the way in which the hybrid is composed (of one monster's head, on another's body, with minor alterations), the hybrid is somewhat similar to many Ultra kaiju, who were designed in similar ways.
- Sea Baragon, Flying Ebirah and King Godzilla make up a trio of monsters which were developed by Kodansya specifically for the series. All the other monsters shown in the manga are either rebuilds of previous mechas, or new generations of existing monsters, an exception being Megalon and Gigan, who simply returned from their absences.