Photo by Scott Sonnenberg (wikipedia)
In recent weeks the presence of Portuguese man o’war (Sp. carabela portuguesa- Physalia phisalis) has been detected at various points on the coasts of Asturias, Cantabria and the Basque Country. Several people have been stung in beaches in Guipúzcoa (Ondarreta and Zarautz) and in Cantabria (Isla) although nobody has yet been seriously injured. Four years ago, the massive presence of the species forced the closure of several beaches in Asturias. Experts believe that the rise in the temperature of the Cantabrian Sea due to climate change has brought the Portuguese man o’war here with warmer waters. The cooler waters of Galicia have so far been free of the threat. El País. The purple Man-o-war is not a true jellyfish, but a colony of hydrozoan polyps. It can in extreme cases provoke a cardiac arrest and death in particularly sensitive persons.
Note the English and Spanish etymology comes from the creature’s air bladder, which looks similar to the triangular sails of the Portuguese ship (man-of-war) Caravela latina (two- or three-masted lateen-rigged ship caravel), of the 15th and 16th centuries. See Wikipedia