So we’re walking on the beach at Bahia Santa Maria, which is a wild, wild beach. Nobody goes there.
It looked like the beach had a fungus. We have no idea what these are. The largest is golf-ball sized, and they’re foamy all the way through, like really light sponges. When they dry they shrink by half and turn brown.
EDIT: Marimo Balls. http://www.theaquariumwiki.com/Aegagropila_linnaeii