Tardigrade

Tardigrades are microscopic multicellular animals commonly known as water bears, or, even more esoterically, moss piglets. Tardigrades are notable for their ability to survive in harsh environments by entering a state similar to hibernation. Tardigrades are the only known animal life able to survive in a vacuum. I just rephrased most of that from Wikipedia and I feel like I'm writing a fourth grade report.

Someone else's fine illustration of tardigrade faces.