Protists, as single-celled organisms are called, come in three varieties, Protozoa (animal-like protists who have some form of locomotion, usually flagella, pseudopod, or cilia), Algae (plant-like protists with the ability to photosynthesize), and various strange protists that are fungus-like, in that they produce "spores."
On the ocean floor near the Bahamas, biologist Mikhail "Misha" Matz from The University of Texas at Austin and his colleagues have discovered a GRAPE-sized protist and the tracks this round single-celled organism makes on the sea floor! Here is the image of the organism making it's way towards some cup corals.
The creature, named Gromia sphaerica, is the first ever single-celled organism found to leave tracks/traces like a bi-lateral, multi-cellular organism. The scientists will go back to analyze this creature and to figure out exactly how it makes it's way across the ocean floor. Amazing stuff. There is so much we still do not know about life on earth and it is amazing that something so small by our standards and so freaking huge by single-celled organism standards can blow science minds in such a manner.
"We used to think that it takes bilateral symmetry to move in one direction across the seafloor and thereby leave a track," explains Matz. "You have to have a belly and a backside and a front and back end. Now, we show that protists can leave traces of comparable complexity and with a very similar profile." (ScienceDaily.com)