Pop popcorn according to package directions. Open bag carefully and pour into large bowl; discard unpopped kernels.
In large microwave-safe bowl, microwave marshmallow creme 1 minute at 50 percent power. Remove bowl from microwave; if desired, stir in icing color. Gently stir in popcorn, mixing until evenly coated.
Lightly spray hands with vegetable pan spray. Shape Marshmallow Halloween Treats into 8 balls; press into Silly-Feet! silicone baking cups. Flatten top of ball slightly where hat will be placed. While the popcorn balls are still warm, press in candy for teeth, nose, eyes and hair, attaching with icing if necessary.
To assemble witch's hat, cut sugar cone approximately 2 inches from pointed tip; attach to cookie with icing. Attach hat to top of popcorn ball with icing.