The mythical sea creature with a human upper body and a fish tail is a mermaid.
In folklore, a mermaid has a human head and torso joined to the tail of a fish. Although the English word emphasizes a female figure, related traditions also include mermen, the male counterparts. Stories of mermaids and similar aquatic beings appear across Europe, Africa, Asia, and Latin America.
Their character varies sharply by tradition. Some mermaids are benevolent beings who grant favors or fall in love with humans, while others are dangerous spirits associated with storms, shipwrecks, drowning, or sailors’ deaths. This mixture of beauty and danger helped make them enduring figures in folklore, art, literature, and modern film.
A mermaid is distinct from a selkie, which is a seal that can assume human form, and a nixie, generally a water spirit from Germanic folklore. Sirens are also frequently confused with mermaids, especially in modern imagery, but ancient Greek sirens were typically bird-bodied beings whose songs lured sailors.