Portuguese Man O' War - Physalia physalis

The Portuguese man o' war, also known as the man-of-war, is a marine hydrozoan found in the Atlantic, Indian and Pacific Oceans. It is one of two species in the genus "Physalia", along with the Pacific man o' war, "Physalia utriculus". Its long tentacles deliver a painful sting, which is venomous and powerful enough to kill fish and even humans.