Tint purchased white frosting with green food coloring, adding a little yellow and blue for a monster-green color. Generously frost one end of the pretzel rod. Create hair by dipping the top of the pretzel rod in chocolate sprinkles. Add white candy dots for eyes; pipe on pupils and a mouth using colored decorator gel (or purchase candy eyeballs). Place 2 colored dots on the neck to create bolts. Stand pretzel rods upright in a bowl or vase filled with candy corn.