I saw some little boys playfully popping the pretty blue balloons washed up in the weed on the beach by stomping them with their bare feet. I gave them a short lecture in marine biology before they encountered any tentacles. I don't think they really appreciated me interfering

pain is a better teacher.
I don't know what the man o war tenticles feel like when they are intact... I think I've encountered bits and pieces of them tho. I did have a bad encounter with those pink moon jellyfish that come through the FL Keys in huge numbers in the fall. It is a bananza for the sea turtles who eat those things like candy. I got stung all over - face, arms, legs, torso, by the moon jellys before I could clamber back into my boat. Obviously, they aren't as bad as man o wars.