Just stumbled upon this thread! I’m originally from Ft Lauderdale, and I miss it every day.. a couple months back, some friends and I were visiting Tybee Island and I found this washed up. I had never seen anything like it! A large disk with a mollusk-like foot underneath with polyps adorning the top side! I eventually found it to be a “Sea Pansy”— a coral that, while common, is relatively exclusive to this area. Apparently they are also capable of bioluminescence! Unfortunately, I lost it in November when that hurricane came through and knocked out power for 72 hours. hope I can find another one next time