The tardigrade is one of my favorite microscopic organisms. They are the ultimate survivalists. They can withstand extreme cold and heat, live years without nourishment, and can even survive space. You need an electron microscope to see them but they are nearly everywhere.
Tardigrades are also known as water bears and resemble water weenies, only they have eight arms and a tiny sucker for a mouth. Their movements are that of something many, many times their size which makes them appear to be too perfect for something so microscopic. The crazy thing is that they've been studied for many years but not too long ago, they were said to be non-ubiquitous. In fact, they are probably in your back yard crawling around in the trees. Check out this video to learn more about them.