The Atlantic Portuguese man o' war (Physalia physalis), also known as the man-of-war, is a marine hydrozoan of the family Physaliidae found in the Atlantic, Indian and Pacific Oceans. Its venomous long tentacles deliver a painful sting, which is venomous and powerful enough to kill fish or (rarely) humans.
One of the most remarkable and beautiful sea creatures you could ever encounter is the lion’s mane jellyfish. It is also the largest known jellyfish. The bell alone can reach up to 8 feet in diameter, and the tentacles may reach over 100 feet in length.
The Most Dangerous Animals in the World There are many dangerous animals in the world but only the deadliest ones make this top ten list. Ordered by the estimated number of humans they kill each year, snakes and scorpions top the list, mainly due to their aggressive behavior and lethal poisons.