A photo from a visit to the California Academy of Science months ago. I think these orange jellyfish are called sea nettle (or chrysaora, for you biological classification nerds out there).
I feel a little unsettled around jellyfish, even if they're in aquariums. When I was 5 or 6, my family took a vacation to Hawaii and I loved going to the beach. However one day while running thru the water, I suddenly felt a burning pain across the back of my neck. I got out of the water and told my parents that I was hurting, and from what I was describing they guessed that a jellyfish that was floating in the water had stung me across my neck. Thankfully though the sting didn't come from a jellyfish that was deadly, and with the help of some medicine my parents gave me, the pain went away in several days. Since then I try to be more cautious on beaches.
Before anyone mentions it, yes, I have heard about how peeing on a jellyfish sting will supposedly reduce the pain. There are some science articles that dispute this though. [link]