Preheat oven to 350 degrees and lightly grease 13x19 in. baking dish.
Heat oil over medium heat, then add bacon and onion and cook until onion is tender.
Add beef cook until meat is no longer pink. Stir in tomatoes, salt and pepper. Stir chopped cheese into beef misture. Spoon mixture into pasta shells and place in baking dish.
Bake shells 3-5 minutes and decorate.
Cut carrots into thin strips. Cut small slit into olives; poke 1 end of thin carrot strips into olives for eyes, Cut red bell pepper into fang shapes. Slice pickles lengthwise into tongue shape. Cut cheese slices into zigzag pattern for teeth.