This striking and rare jelly has brilliant, multicolored tentacles trailing from a translucent, pinstriped bell. It also has tentacles around the rim of its bell that it can quickly coil and uncoil. This mysterious jelly is semi-benthic, sometimes spending its time on the seafloor.
Blooms of the flower hat jellies make swimming in waters off Argentina hazardous. The sting of this jelly is painful, leaving a bright rash. In Brazil, blooms of the flower hat jellies interfere with shrimp fishing; the jellies clog their nets and drive shrimp away, probably to deeper water.
Jellies have no head, heart, brain, bones, cartilage or real eyes, yet they're among the major predators in the ocean. Their stinging cells are among the most complicated cells found anywhere in the animal kingdom.