This is how they looks like (images found from google image):
More photos after the Read More.
Nano size Marimo
Marimo doing Photosynthesis releasing Oxygen
They really look cute, green, round shape. I ordered 2 Marimo from local forum, size around 3-5cm in diameter, that I would like to put in a bottle on my office table. Will update with more photo once I receive my Marimo.