Sweet and spicy, this fuss-free Boston butt is an instant crowd pleaser. In a medium bowl, stir together cola and ketchup; pour into a 6-quart slow cooker. In a medium bowl, stir together salt, garlic powder, onion powder, paprika, and red pepper. Rub pork with oil. Rub spice mixture on pork, coating all sides. Place in slow cooker.