Greek Creatures and Monsters
Monster myths developed for a number of reasons. To explain unusual natural phenomena, often the occurrences would take the form of a monster. For example, Charybdis (the whirlpool) and the Clashing Rocks were the cause of many sailors' deaths. To account for the sunken ships and numerous deaths, these became monsters, eager to consume victim after victim.
Monsters could also explain how wicked people might be punished by the gods. An evil king might be changed into a wolf, or a beautiful maiden who had offended the gods by her vanity might become a hideous creature. Monsters also symbolized the darkness and evilness of the underworld. For example, Cerberus was the three-headed dog who guarded the gates of Tartarus.
Another reason for the creation of monsters was the excitement they added to hero tales. If a hero fought and killed a bear, that was enjoyable or entertaining to relate. If a hero fought and killed a nine-headed beast or a creature part lion, part serpent, and part goat-- that was excitement or adventure.
Monsters, however, were not always pure imagination. Perhaps a child was born with a birth defect (one eye or six fingers) and the villagers were afraid. The story might be circulated that this creature was cursed. Exaggerations of the deformity might then occur and, instead of six fingers, the child might be said to have ten hands with six fingers on each hand.
Thus, monsters could be real animals or real people with various deformities, they could be personifications of society's fears of the sea or of the forest or of anything unknown, or they could be simple natural occurrences which the people of the day could not explain.