A species of space monster that lives in the seas of Planet Valky. Samekujira was brought to Earth by its master Alien Valky, an alien that plotted to take control of the Earth’s oceans. Samekujira is adept at fighting in water, tackling enemies with itss sharp, pointed nose.

On Alien Valky’s orders, Samekujira destroyed many tankers at sea. After sinking the Nipponmaru ship off the coast of the Izu Peninsula, the space monster evaded ZAT’s counterattacks and disappeared. The next day, Samekujira sank the Hibimaru ship and was attacked by ZAT’s Sky Whale and Super Swallow as it came to the surface, but again Samekujira retreated underwater.

The day after that, Samekujira came ashore and destroyed several buildings. Ultraman Taro appeared to stop the space monster. Samekujira fought back with tackles and flung Taro off its back when Taro tried to ride the monster. However, although Alien Valky came to help, the alien was of no use as Taro broke the monster’s nose, and then finished Samekujira off in an explosion with his Strium Beam.