This elemental water is not to be mistaken with the serpent-like creature. The real elemental water was actually the bright light inside the floating water. It floats on sea, pretending to be beacon light to the confused navigators. When it was too close, it was already too late to turn back, as a serpent creature curls around its bodily water will definitely devoured those poor souls on the ships. As their body devoured by the serpent, their souls will be instead eaten by the elemental water. This is how this 2 creature survives as symbiosis.
It was said, the size inside the elemental water body fluid, is bigger than its outlook and it was also rumored, the elemental water came from a lost civilization which act as a weapon. The bright light shows the whole lost civilization's vast devoured souls.
If it detected hostility, it will submerge inside the seawater and will counter attack accordingly mainly with the help of the serpent creature.
From time to time, this fearful creatures, will float to nearby land, and devours unsuspecting villages and leave the area as silent as it came.