The term 'kind of shell' can refer to two different types of shells. The first is a taco shell, which is a type of edible shell made from corn or wheat tortillas and is typically filled with various ingredients such as beef, cheese, lettuce, tomatoes, and sour cream. The second is a patty shell, which is a type of edible shell made from pastry dough and is usually filled with savory ingredients such as ground beef, onions, and spices. Both taco shells and patty shells are popular items in Mexican and American cuisine.