Mine is a giant oyster shell.
This post may include affiliate links.
there was a giant manatee right next to me when i looked down and i almost had a heart attack. There was a lot of algae (or seaweed whatever that stuff is) that day in big groups. I had walked out to the sand bar and i though there was just a big algae group next to me but then it started moving and i realized it was a manatee. ik they are harmless but it gave me a huge fright.