Tardigrades are microscopic eight-legged animals that can withstand temperatures from near absolute zero to boiling water, absorb extreme doses of radiation, go without food or water for ten years, and even survive the vacuum of space. They can even be completely dried out and ride on the wind to a new home, where they rehydrate again.
Oh, and you’ve probably eaten them - these water-dwelling super-critters live not only on wild mosses and wet plants, but on grocery store produce like lettuce and spinach. Don’t worry, though. They’re totally harmless.