In some stories, human sacrifice is necessary to propitiate these sea monsters. The sacrificial victim is often young virgin who may, as in the cases of Andromeda and Angelica, be lucky enough to be rescued at the last moment by a male hero.

(image source: MythNET)
Piero di Cosimo
Perseus Rescuing Andromeda

(image source: Carol Gerten)
Joachim Wtewael
Perseus Rescuing Andromeda, 1611

(image source: Carol Gerten)
Jean-Auguste-Dominique Ingres
Roger Saving Angelica, 1839

Some sea monsters, who remained located in a single place, where they prayed upon passing shipping, were represented as female. The most famous are Scylla and Charybdis, who, in Greek mythology, were two immortal and irresistible monsters whom Odysseus encountered in his wanderings, and were later localized in the Strait of Messina (between Italy and Sicily).

The mysterious depths of the ocean, and the potentially destructive aspects of the sea, were also personified in female forms, such Mermaids and Sirens, the latter also memorably encountered by Odysseus.

Many traditions also contain stories about devastating floods. The Babylonian epic of Gilgamesh tells of an apocalyptic flood, from which was almost certainly derived the Old Testament story of Noah and the flood told in Genesis. The biblical flood is an example of God using water to destroy the wicked and evil-doers.

(image source: Carol Gerten)
Michelangelo
The Flood (detail from the Sistine Chapel ceiling), 1508-12