Jack-O-Lantern Dessert

I have been making this for quite a few years for my kids. Now the grandkids get some Halloween fun for dessert. They come to spend the evening with Gramma because I have a more lucrative neighborhood. Mmmmnnn.... 
Do you have a 12" pizza pan? You're already moving towards this fun dessert. I found an ad in a magazine in 1980. It featured a brownie mix, frosting, M & Ms, and some candy corn. You make up the brownie mix according to directions putting it in the pizza pan Tint the frosting orange or if you're lucky, use an orange frosting. When the brownie pizza is cool, cover it with the orange frosting. Now the fun begins. Using just the brown M & Ms, make the Jack-0-Lantern eyes. Using green M&Ms, make the nose. With more brown M&Ms, create a smile and using the candy corn, create the teeth. Here's what he should like like: