With jellyfish, it’s hard to know where to start. Or where, indeed, they end. (See: the Portuguese man o’war, which is not actually one jellyfish but a siphonophore, or, colonial organism, of different zooids working in symbiosis.)
While the octopus gets a good rap (see, for example: Peter Godfrey-Smith, Other Minds: The Octopus and the Evolution of Intelligent Life) because it is clever,
amazingly well-developed, thoughtful, etc etc, jellyfish have a less rarefied reputation. They just drift about mob-handed, stinging people.
But I like them. The photographer Brassai finds them on the walls of Paris.
Biologist Ernst Haeckel, while unfortunately an inaccurate proto-Nazi, did create the most stunning jellyfish illustrations, published in 1904 in Kunstformen der Natur (Art Forms in Nature).
Here, from Kurt Stueber’s collection of biology books, are Haeckel’s charts showing the discolabe:
and the charybdea:
Lastly, I like jellyfish because they would seem to inhabit or at least inspire the classic video arcade game of Pac-man, 1980.