To cover your cookies and add color, I recommend using jimmies (the long, thin sprinkles shown) in Halloween colors like green, purple, and orange. Nonpareils (tiny round sprinkles) are another option, which tend to keep their crunchy texture after baking. Candy eyeballs can be found at your local grocery store in the baking aisle, at Joann Fabrics, or on Amazon: - Wilton Edible Candy Eyeballs, 0.88 oz - Wilton Assorted Candy Eyeballs Set, 3-Packs Chocolate chips make great monster horns, ears, or fangs, and m&m's candies look like warts or spots. Try using what you have on hand - broken pretzel pieces, cashews, peanuts, and slivered almonds could make great monster body parts!