Corn smut is caused by an Ascomyetousfungi. It is considered a parasite of corn and grows and deforms the corn seeds.

I think it is parasitism because corn smut is the disease on a corn crop caused by fungi and so, fungi is taking nourishment from the corn crop but damaging it at the same time (corn smut..).

Corn smut is a plant disease caused by the pathogenic fungus Ustilago maydis that causes smut on maize and teosinte

smut

Some people do. In some fancy restaurants, it's called "corn mushroom."