Bring a large pot of water to boil over high heat. Cook pasta according to package directions and drain

Return pasta pot back to stovetop and reduce heat to medium. Add the pumpkin puree, cheese, milk, garlic pepper, salt and cayenne. Cook, stirring continuously, until mixture begins to bubble and cheese is melted.

Pour in cooked pasta. Continue to cook for an additional 1-2 minutes to coat the shells. Turn off heat and cover. Let stand for another 2-3 minutes before serving.