Fury of the South Sea (南海の怒り Nankai no Ikari) is the twenty-third episode of Ultra Q.
Following the destruction of a fishing vessel by a gigantic octopus, the lone survivor named Yuzo, the son of the ship's captain, is washed ashore nearby Compass Island. He is rescued and cared for by the beautiful native girl, Anita and the two begin to develop affections for one another. However, the island's chief declares the relationship a sacrilage against their god, the giant octopus Sudar. Tensions increase further following the arrival of Jun and the others as they investigate the mysterious ship disappearances in the area of Micronesia. After saving Anita's younger brother from the tentacles of Sudar, Jun and Ippei escape the island to warn the authorities of the monster. Upon their return, they find that the natives are preparing to offer their friends as a sacrifice to the giant octopus. The military arrives and drops bombs upon Sudar, providing a distraction that allows Jun and Ippei to rescue the others. Driven from the sea, the wounded Sudar comes ashore and attacks the village. The natives fight back, challenging the beast with spears and fire. With the help of Yuzo and Jun, Sudar is finally defeated and collapses before it can return to the sea. Having avenged his father's death, Yuzo remains on the island with Anita, as Jun and the others return to Japan.
- Ultra Q Volume 6 features episodes 21-24, & Volume 7 Total Natural Color Blu-Ray features episodes 22-25.