Spirochetes are a group of spiral-shaped bacteria known for their unique corkscrew motility, which allows them to move through viscous environments. They belong to the phylum Spirochaetes and include notable pathogens such as Treponema pallidum, the causative agent of syphilis, and Borrelia burgdorferi, which causes Lyme disease. These bacteria are characterized by their flexible cell walls and can be found in various environments, including soil and aquatic habitats, as well as in the bodies of animals and humans.