Cosmos atrosanguineus, aka chocolate cosmos, is a plant from Mexico that can grow up to about 24 inches high and has a maroon-colored flower. It’s famous for it’s chocolate-y scent, but don’t be fooled. No part of this plant is edible. This plant is not actually fertile, so it produces no viable seeds. It is extinct in the wild. They currently only propagate by the division of tubers.
(Sources: 1, 2)