Draw pattern for coffin on a piece of cardboard and cut out for pattern.
Preheat oven to 350 degrees.
Remove dough from package and divide in half.
Roll dough out on a lightly floured surface to 1/8 in. thickness and cut into coffin pattern.
Place cookies 2 in. apart on ungreased cookie sheet.
Bake about 6 minutes or until firm, but not browned. Cool completely.
For marshmallow filling, combine frosting and marshmallow creme until well-blended.
Spread marshmallow filling on half of cookies and place the other half of cookies on top of the filling.
Roll cookie edges in sprinkles and decorate cookies with icing and decors, as desired.