Combine the marshmallow creme with the water in a medium bowl and microwave it on high for 30 seconds. If you don't want to use the microwave, use warm water from your tap. Stir until the marshmallow creme dissolves, then cool uncovered in the refrigerator for 1 hour, or until cold.
Add the Dream Whip to the bowl and mix with an immersion hand blender for about 30 seconds. If you don't have a hand blender you can use an electric mixer, but only mix for about 15 seconds.
Add the powdered sugar and salt and mix for another 30 seconds.
Add the butter, vanilla and caramel flavorings and mix just until combined. Store covered in your refrigerator until needed.
When you are ready to serve the drinks, pour a can of cream soda into a 12-ounce glass or mug. Be sure to leave about 1/2-inch of room at the top.
Use the blender to mix the foam for 5 seconds, or until some large bubbles form in the topping. Spoon 3 to 4 tablespoons of topping onto each drink and serve.