The mythical creature with the top of a woman and the bottom of a fish is a mermaid. Mermaids are often depicted as beautiful and enchanting creatures with long flowing hair and a fish tail. They are often associated with the ocean and are said to lure sailors to their doom with their irresistible singing. Mermaids have been present in myths and legends from various cultures around the world, and continue to capture the imagination of people today through books, movies and other forms of media.