cecaelia

Etymology
Apparently coined around 2007 on a discussion thread on Seatails, a mermaid-enthusiast messageboard created by Kurt Cagle, who created a Wikipedia article on the cecaelia (originally “Cecælia”), inspired by Cilia (a cilophyte in “Cilia”, a seven-page short comic story published in issue #16 of the Vampirella comic magazine, released in March of 1972),, , and the song “Cecilia” by Simon and Garfunkel, about a fickle and demanding lover (according to Cagle).

Noun

 * 1) A composite mythical being, combining the head, arms and torso of a woman (more rarely a man) and, from the lower torso down, the tentacles of an octopus or squid as a form of mermaid or sea demon.