OK--what the heck is this??? Well it is one of the only types of fungus that can be claimed as an exclusive Native American mushroom. It does have relatives abroad, and if you read my post on wild rice you will see that this fungus as cousins elsewhere in the world--providing for some very interesting food choices for humans in far corners.
Like it's cousins, it infects the parts of the stalks of types of grass, in this case, maize. It seems odd to think of corn as grass, but it is. Smut fungi infect, or rather set up shop in host environments and seem to have beneficial, sometimes, almost symbiotic relationship that has results in food for humans.
This is also called "maize mushrooms"--it is a fungus that infects the kernels of developing corn kernels and causes the host to swell and grow into grotesque shapes and sizes, but doesn't infect the whole plant. Suffice to say that it's weird, but an important food source, most especially in Mexico.