There are all kinds of popping corn in different degrees of hull hardness, size, shape, and color, and there are two different ends of the popped corn spectrum: flakes that are butterflies and flakes that are mushrooms. (Flake is the formal term for a single popped kernel.) Butterflies are flakes that sprout wings when they pop, extending far beyond the hull and offering more crisp crunch. Mushrooms are kernels that pop into smooth, round balls that are softer but lack butterflies’ elegance. The distinction is good to know if you are making popcorn balls or caramel corn, as you want popping corn that yields mostly mushrooms—they are sturdy enough to be mixed—although in caramel corn especially, a measure of butterflies adds welcome texture.