Add cake mix, water, oil and egg to a mixing bowl and mix well. Pour into a large, gallon size, resealable bag. Seal. Snip the tip and pipe batter into prepared pan. Fill pans about half full of batter. Bake for 11-13 minutes or until done. Let set in pan for 5 minutes before removing from pan and cooling on a wire rack. Let cool completely before icing.

In a large mixing bowl, add sugar, half and half and vanilla. Whisk well until combined making sure mixture is "ribbony" when lifted with whisk. Divide into four separate bowls. Color each bowl a separate color. Pour each color into a shallow bowl or dish and swirl with toothpicks to mix colors.

Dip donuts into icing and twist to swirl colors. Lift and let drizzle a bit before flipping over and letting drip onto a wire rack. Add sprinkles and stars.

Repeat until all donuts are frosted.