While having a nice relaxing swim you notice what you think is a plastic bag in the distance. You ignore it and doze off a bit. Hours later you wake up to a stinging pain on your back and see a big clump of man o wars almost looking humanoid staring at you maybe they don't have eyes. "Human shouldn't sleep on the sea... the seas are restless and can be more deadly than me. If you couldn't tell I'm a hivemind of Siphonophores. I'd shake your hand if it wouldn't hurt you."