Portuguese man-of-war: see jellyfish jellyfish, common name for the free-swimming stage (see polyp and medusa ), of certain invertebrate animals of the phylum Cnidaria (the coelenterates). The body of a jellyfish is shaped like a bell or umbrella, with a clear, jellylike material filling most of the
..... Click the link for more information. ; polyp and medusa polyp and medusa, names for the two body forms, one nonmotile and one typically free swimming, found in the aquatic invertebrate phylum Cnidaria (the coelenterates).
..... Click the link for more information. .

Portuguese man-of-war

Any of various floating, warm-water marine cnidarians (genus Physalia, class Hydrozoa) found worldwide but mostly in the Gulf Stream and the Indian and Pacific oceans. The medusa-form body consists of a translucent, jellylike, gas-filled float, which may be 3–12 in. (9–30 cm) long. Polyps beneath the float bear hanging tentacles up to 165 ft (50 m) long. Nematocysts on some polyps paralyze fish and other prey. Other polyps then attach to, spread over, and digest the victim. A third type of polyp is involved in reproduction. The painful sting of Physalia can cause fever, shock, or disruption of heart and lung function.

a long tentacled jellyfish whose sting can be deadly. [Zoology: NCE, 1408]

See : Deadliness