What is very unusual about creatures known as Tardigrades?

Tardigrades can withstand temperatures ranging from - 273 degrees celsius to 150 degrees celsius, as well as take a thousand times more radiation than humans, and survive in the vacuum of space.

These creatures contain 17.5% of foreign DNA, and are able to bought back and re-hydrated, as well as lay eggs within 30 minutes after being dried and exposed to space vacuum for ten days.