The Atlantic Portuguese man o' war (Physalia physalis), also known as the man-of-war, blue bottle, or floating terror, is a marine hydrozoan of the family Physaliidae found in the Atlantic Ocean, as well as the Indian and Pacific Oceans. Its venomous tentacles can deliver a painful (and sometimes fatal) sting. Despite its outward appearance, the Portuguese man o' war is not a jellyfish but a siphonophore, which, unlike jellyfish, is not actually a single multicellular organism, but a colonial organism made up of specialized individual animals called zooids or polyps;