Unlike other comb jellies, the body of cestids is greatly flattened, and drawn out into a long ribbon-like shape. The two tentacles are greatly shortened, and two of the four ciliated comb rows are reduced. The unusual body form allows the animals to swim by means of muscular undulation, as well as by using their cilia. The largest species, belonging to the genus Cestum, can reach 1 metre (3.3 ft) in length.
Not sure if it is them or others, but I am also gettibg stung by something most dives!!!
The sea, once it casts its spell, holds one in its net of wonder forever - Jacques Cousteau