Heat oven to 350°F. Grease and flour one 8-inch round cake pan and one 2.5-liter ovenproof bowl.
In medium bowl, combine flour, cocoa, baking soda, and salt. In large bowl, with electric mixer on high, beat sugar and butter until light and fluffy, about 3 minutes. Add eggs one at a time. Reduce mixer speed to low; add flour mixture, alternating with buttermilk, until combined. Divide batter between prepared pan and bowl.
Bake cakes until a toothpick inserted in center comes out clean -- about 25 minutes for cake in pan and 40 minutes for cake in bowl. Transfer both to wire rack. Cool 10 minutes; invert and cool.
In medium bowl, over simmering water, with electric mixer on low, beat together sugar, egg whites, water, corn syrup, and cream of tartar until combined. Increase mixer speed to high, and beat 10 to 12 minutes, scraping sides of bowl, until stiff peaks form. Add orange food coloring and beat until combined.
Place cake-pan layer on cake stand. Spread 1/2 cup frosting over top. Place bowl cake on top, flat side down. Spoon remaining frosting into pastry bag fitted with small star tip. Starting along bottom of cake, pipe frosting to look like squiggly hair. Add sprinkles in random pattern. Attach yellow round jelly to one end of Twizzler to make leg and foot. Insert other end of Twizzler into side of cake. Repeat to make 7 more legs. To make eyes, wrap doughnut jellies around lollipops, pipe dot of frosting onto each lollipop and attach marshmallow, then attach M&M to each marshmallow for pupils. Insert lollipops into top of cake. Trim licorice to make antennae, stick marshmallow onto ends, and insert into cake. Shape red taffy into mouth, and cut out fangs from white taffy. Press fangs in mouth; attach mouth to cake. Press jellybean into cake to make nose.