Portuguese man-of-war (Physalia physalis) washed up on a beach. Although this organism resembles a jelly-fish, it is in fact a siphonophore - a colony of minute specialised individuals. Each individual has a specific function such as making up the dome like bubble at the top or the stinging tentacles below, among other roles. Also known as a bluebottle, this organism can inflict a painful sting. Although rare, in severe human cases the victim may suffer cardiovascular and respiratory collapse.