I've seen a few of these washed up on the shore when I was in Thailand. Definitely wore lycra when I went diving!
Do you focus on jellyfish in your studies? I tried eating jellyfish in Hong Kong and when I learned more about the nutritional facts I thought that it could make a decent filler/mixer for ground meats in case beef/pork ever got to be too expensive on its own.
Don't go close to them when they're washed up, they can still sting.
I'm actually focusing my undergraduate research on fiddler crabs at the moment. I typed up posts about them previously but nobody seems to find them interesting so I stopped doing that.