The 10th saucer creature summoned from Black Star by Commander Black. Nova emits a red poisonous gas from its mouth that causes people to go violently insane, and attacks with its whip-like tentacles and sickle.

Nova flies to Earth in secret and, disguised as a teru-teru bozu Japanese doll, secretes the poisonous gas, causing people to attack one another. It changes to child-size and hypnotizes Toru Umeda, taking him around town to infect more people with its violent gas, and sending the town into chaos.

Gen Otori and Toru’s foster family, the Miyamas help bring him back to sanity. Nova retaliates by turning giant and attacking the town, and the defense force’s attacks has no effect on it.

When Ultraman Leo arrives, Nova attacks him by shooting destructive beams from its eyes and choking him with its tentacles, but Leo counters with a combination of his Shooting Beam and Energy Beam Ball, killing Nova in an explosion.