Preheat oven to 350°F. In a saucepan, melt unsweetened chocolate and marshmallows. Add corn syrup. While chocolate is melting, place puffed cereal in a shallow pan. Bake for 10 minutes. Then, place in prepared bowl. Pour chocolate mixture over puffed cereal. Stir to coat cereal evenly. Form into 8 cones, flattening large end to make brim. In a double boiler, melt chocolate chips. Dip cones into melted chocolate to coat. Place on waxed paper to cool and harden.