Aegagropila linnaei (marimo)

My Marimo floating in his freshly changed cold water.

Marimo is a species of filamentous green algae (Chlorophyta) found in a number of lakes in the northern hemisphere. A marimo is a rare growth form of the species where the algae grow into large green balls with a velvety appearance. Colonies of such balls are only known to form in Iceland, Scotland, Japan and Estonia.

-Wiki