Make butterscotch pudding as directed on box, using 2 cups of the milk. Stir in 20 drops red food color and 25 drops of the yellow food color. Refrigerate 30 minutes. Make banana cream pudding as directed on box, using remaining 2 cups milk. Stir in remaining 20 drops yellow food color. Refrigerate until ready to use.
To assemble, place about 1/4 cup banana cream pudding in bottom of each of 6 (8-oz) martini glasses. (Cover and refrigerate remaining banana cream pudding for another use.) Top each with about 1/3 cup butterscotch pudding and about 1/3 cup whipped cream. Garnish with candy corn.