It's long, black, and wrinkled, and a standard ingredient in mole sauces. Ancho chiles are sometimes mislabeled as pasillas. It has a fruity flavor. These look a bit like large dried cranberries. They're also sold fresh.
Peppers often become hotter as they ripen, and hotter still when they're dried.
Dried peppers tend to have a richer, more concentrated flavor. To tone down the heat of a pepper, cut it open and remove the seeds and the white ribs. When working with peppers, wear rubber gloves or, in a pinch, coat your hands with vegetable oil. Wash your hands carefully afterwards. Chiles don't freeze well.