The most dangerous cactus on earth. The Arizona Teddy Bear cactus or Jumping Cholla has needles so evolutionarily advanced that at the lightest touch, microscopic backward facing hooks grab onto you and when removed they rip out chunks of flesh causing serious bleeding. In the wild when attached to an unsuspecting animal, these segments will grow taproots into the humid flesh and slowly kill the animal while it's frantic running to escape the pain leads it to disperse the plant far and wide in the arizona desert.