The monster OP's picture is reference to is called the Ningen:
>these so-called "Ningen (人間, "Ningen", meaning "human") are said to be completely white in colour with an estimated length of 20 to 30 meters.
>Eyewitnesses describe them having a human-like shape, often with legs, arms, and even five-fingered hands.
>Sometimes they are described as having fins or a large mermaid-like tail instead of legs, or even tentacles.
>The only visible facial features are the eyes and mouth. According to one account, crew members on deck observed what they initially thought was a foreign submarine in the distance.
>When they approached, however, it became clear from the irregular shape of the thing that it was not man-made--it was alive.
