Plants are pretty darn amazing. The vast majority of them have green foliage as a result of having chlorophyll. Chlorophyll absorbs light, and the plants then use this light to convert water and carbon dioxide to sugar (for their use) and oxygen (released from the plant as a by-product, but pretty important to us). If that's not impressive enough, consider this... there are plants that lack chlorophyll. So how do these plants obtain the energy they need to grow and reproduce? One way would be to steal nourishment from other plants, and that's just what Conopholis americana (known as Squaw Root, Cancer Root, and Bear Corn) does.
As you can see in the photograph above, no part of these plants is green, and the leaves consist simply of brown scales. The roots of Cancer Root are parasitic on the roots of Quercus spp. (oaks) and sometimes Fagus grandifolia (American Beech), providing the plant with water, nutrients, sugar, and starches from the host plant. This parasitic relationship is said to result in the formation of large, round knobs on the roots of the host tree (perhaps leading to the common name Cancer Root).
If you reside in eastern North America, check an oak woods near you to see if you can find this odd parasitic plant springing up from amonst the oak duff.