1Heat oven to 350°F (325°F for dark or nonstick pans). Place paper baking cup in each of 24 regular-size muffin cups.
2Mix and bake cake mix as directed on box for 24 cupcakes. Cool 10 minutes; remove from pans to cooling rack. Cool completely, about 30 minutes.
3On large round platter or pizza pan, arrange cupcakes, placing them close together. In medium bowl, mix food color and frosting. Spread frosting over cupcakes and spaces in between to create 1 large circle of frosting. Squeeze 1 large dot of black gel in center of frosting. With gel, draw concentric circles around the dot, spacing them about 2 inches apart. To create the web design, drag a toothpick from the center dot to the outer edge of the circle, about 12 times. Place plastic spiders on web. Store loosely covered.