A Kaiju that wanders within the Monster Graveyard, a place in the “Ultra Zone” in space. Although incredibly powerful, it is calm by nature and typically doesn’t initiate violence.

After being sighted in the Monster Graveyard by Arashi and Ide on patrol in outer space, Seabozu accidentally collides with Japan’s first lunar rocket and falls to Earth. After being attacked by Jet VTOL aircraft in the middle of Tokyo, Seabozu begins climbing a skyscraper and howls towards space.

The SSSP realizes that Seabozu just wants to return to the Monster Graveyard and begin a joint operation with the Lunar Rocket Research Center to send Seabozu back into space on the Lunar Rocket 2, but Seabozu knocks it over just before launch. Next it is carried into the atmosphere by Ultraman after tiring it out in hand-to-hand combat, however, falls to Earth as Ultraman’s energy runs dry. He was eventually returned to the Monster Graveyard on the newly repaired and refurbished “Ultraman Rocket”.