Aegagropila linnaei, commonly known as "marimo," is a type of green algae that forms spherical clumps. These unique formations can be found in freshwater lakes, particularly in Lake Akan in Japan and Lake Hokkaido. Marimo thrives in cool, shallow waters and is often associated with clear, nutrient-rich environments. The algae grow slowly, typically at a rate of about 5 millimeters per year. Marimo is not only a natural wonder but also holds cultural significance in Japan, where it is considered a symbol of good luck and longevity. Conservation efforts are in place to protect this delicate species from environmental threats.