I've only been stung once, by a Man-O-War and that's pretty good considering I grew up near South Padre Island (no hotels, then. It was totally undeveloped). It tangled around my leg and I pulled it off without realizing what it was, at first. It made my hand red and a few streaks on my leg, but no big deal really. I may have some lack of sensitivity to any allergen effects, which I normally do. I've seen people hospitolized, though, from the tiniest contact. There are so many of those type of jellyfish there, during certain times of the year, that you can't walk on the beach for a few days, without stepping on one.
Rocketturtle, DAMN! ... those things get to be a meter in diameter! ... are you a marine biologist or simply interested in jellyfish? ... or is it the discovery of any new species that holds your attention?