They are desert-dwelling plants that have a really unique survival mechanism, to live through droughts: when they don't get enough water, they retract their roots, curl up into a ball, and let the wind blow them around, until they find a new place to root and flourish. In fact, they can last up to 50 years (50 YEARS!) without water!
When you get them, you simply place it in a shallow dish of water and it will start coming "back to life" within a few hours! Pretty cool, no?