1Heat oven to 350°F (325°F for dark or nonstick pans). Make and cool cake as directed on box for 24 cupcakes.
2Stir together frosting and 2 or 3 drops food color. Frost cupcakes with blue frosting; pull up on frosting, using metal spatula, so frosting looks like waves.
3To make fishing poles, cut each straw to make one 3-inch piece. Cut dental floss into 3 1/2-inch lengths. Attach piece of dental floss to end of each straw, using needle, to look like fish line. Attach 1 fruit snack to end of each piece of dental floss. Decorate each cupcake with a fishing pole. Store loosely covered.