Man-o-War (Physalia physalis) カツオノエボシ – Portuguese Man-O’-War – size 10 cm
The Man-o-War is a type of jellyfish that floats. They have a very strong sting. I know have been stung many times. They float with the wind so if the wind is onshore look at the beach. If they are on the beach they are probably in the water too. They could just be starting to come in too, so you never really know. The Pacific ones were recently considered as a separate species from the Atlantic ones. Now they are considered as the same species. The Pacific Man-o Wars are smaller getting to about 10 cm across the float with tentacles extending up to 3m. The Atlantic ones get much larger. If you do get stung, it is best to remove the Man-o-War as soon as possible. The blue parts of the tentacles are what stings. The skin on your fingertips is thicker than elsewhere. I often just grab the tentacle with my fingertips and carefully pull it off of other people. Be careful not to get tangled up in it and watch for more of them on your way out of the water. I have not found an easy way to stop the pain but so far it has always eventually gone away. Don’t ever rub the tentacles away it just makes it worse. Kauai 2003
Same Man-o-War showing more but not all of the tentacles. Kauai 2003