This evening I went out for a swim. I think I was about 10 minutes out when my arm was stung by something. When my legs were stung I realized it was not the little stings that just go away and turned towards shore. When I got out of the water, I already had welts. Three nice strips across my right quad and a few random other spots on both legs and my left arm. Some treatment (salt water and fresh water rinse, vinegar rinse, and shaving the stung areas) and a couple of hours later the welts are mostly gone and it is more of a tingle than pain. Now I can add jellyfish to the list of creatures that I have not only seen, but also encountered.