Preheat oven to 350°F. Grease and flour a 9" x 13" pan. Prepare cake batter as directed on package. Pour cake batter into prepared pan and bake for 25 to 35 minutes or until toothpick inserted into cake comes out clean.
Let cake cool completely and remove from pan. Pour 1 packet of Duncan Hines® Frosting Creations™ Bubble Gum Flavor Mix into 1 can of Duncan Hines® Frosting Creations™ Frosting Starter. Stir until evenly blended. Repeat with second packet and can.
Frost cake with the Bubble Gum frosting you just created. Transfer any additional frosting to a piping bag with a decorator tip. Pipe borders and decorative elements. Decorate with candy and serve.
Tip: To unify your candy design, stick with either one shape of candies or a specific color palette.