1Heat oven to 375°F. In medium bowl, stir cookie mix, butter and egg until soft dough forms. On ungreased cookie sheets, drop dough by rounded tablespoonfuls 2 inches apart.
2Bake 11 to 14 minutes or until edges are light golden brown. Cool 1 minute; remove from cookie sheets to cooling racks. Cool completely, about 15 minutes.
3Stir enough food color into frosting until desired green color. Frost cooled cookies. Use black or white decorating gel to make "ghoulish" faces on cookies. Use marshmallows and baking bits to decorate.