Heat oven to 350 degrees F. Line 18 regular size muffin cups with white liners.

Beat cake mix, egg whites, milk and oil in large bowl with mixer on low speed 1 minute until blended; increase speed to medium and continue to beat 2 minutes or until batter is smooth. Divide batter among muffin cups, filling each 2/3 full.

Bake 20 to 22 minutes until a wooden toothpick inserted in centers comes out clean. Cool in pans on wire rack 10 minutes before removing cupcakes to rack to cool completely. Frost cupcakes with vanilla frosting.

To decorate: Slightly flatten marshmallows with the palm of your hand. Insert a lollipop stick into each marshmallow. With the black decorating pen, using the photo as a guide, draw the skeleton mouth along the bottom of each marshmallow. Draw 2 nostrils above the middle of the mouth, as shown. Make the eyes with dabs of the black writing gel.