New Venomous Sea Creature Washes Up in Japan, Named After a Samurai Warlord

A newly identified venomous siphonophore, Physalia mikazuki, washed ashore in Sendai Bay, northern Japan, marking a rare tropical intrusion into temperate waters; researchers say its smaller blue float and distinct tentacles distinguish it from related species, and climate-driven warm currents likely carried it north, raising public safety and ecological concerns as marine life shifts; the name honors Date Masamune’s crescent-moon helmet.