To prepare the corn, peel back the husks, remove the silk, and place the husks back over the corn cob. Soak the corn in a large bowl of cold water for 30 minutes.
Meanwhile, heat the grill to medium-high heat. Place the corn directly on the grill grate, cover, and grill turning once or twice using tongs, about 15 to 30 minutes.
While the corn is grilling, in a small saucepan, place the butter, sour cream, paprika, chili powder, and red pepper over medium-high heat. Stir occasionally until butter is melted and the ingredients are incorporated. Season to taste with salt and freshly ground black pepper. Pour into a baking dish.
Shuck the corn and place into the butter bath and coat evenly, using a pastry brush to cover the ends and sides. Garnish with scallions and serve.