Teras tis thalassis was released in the year 1959。Teras tis thalassis is also called as Behemoth the Sea Monster, Ungeheuer von Loch Ness, The Giant Behemoth, Drago degli abissi, Behemoth。

The dumping of radioactive waste in the ocean disturbs a prehistoric monster than can project electric shocks and radioactive beams. After terrorizing the English coast, it is discovered that if the creature is destroyed with conventional weaponry it would spread a dangerous amount radioactive contamination over the entire country, with this fact preventing the military from attacking the monster as it nears London.