Preheat oven to 350°F.
Line 15 regular-size (2 1/2-inch) muffin pan cups and 15 small (about 1-ineh) muffin pan cups with paper muffin cups.
Prepare cake mix according to package directions.
Spoon batter into muffin cups.
Bake 10 to 15 minutes for small cupcakes and 15 to 20 minutes for regular-size cupcakes or until cupcakes are golden and wooden toothpick inserted in centers comes out clean.
Cool in pans on wire racks 10 minutes.
Remove from pans to racks; cool completely.
Remove paper liners.
For each snowman, frost bottom and side of 1 regular-size cupcake; coat with coconut.
Repeat with 1 small cupcake.
Attach small cupcake to regular-size cupcake with frosting to form snowman body.
Attach marshmallow to small cupcake with frosting to form snowman head.
Attach inverted peanut butter cup to marshmallow with frosting to form snowman hat.
Use pretzels for arms and small red candies for buttons.
Pipe face with decorating gels.
Repeat with remaining cupcakes.