Preheat the oven to 400°F (200°C). In a large mixing bowl, combine ground beef, ground pork, breadcrumbs, egg, onion, garlic, parsley, salt, and pepper. Mix until just combined. Do not overmix. In a small bowl, mix together marinara sauce and 0.25 cup of water; set aside.

Using your hands, form the meat mixture into 1-inch meatballs. Place them on a baking sheet lined with aluminum foil, leaving some space between each meatball. Bake for 15-20 minutes or until cooked through and lightly browned.

While the meatballs are baking, prepare the "eyes." Cut the string cheese into 0.25-inch rounds. Cut the black olives in half and then into quarters to create the "pupils." Cut the red bell pepper into small triangles for the "eyelids".

Once the meatballs are done, let them cool for a few minutes. Using a toothpick, poke a small hole in the top of each meatball. Insert a string cheese round into the hole, pushing it in until it's secure. Place a black olive quarter on top of the string cheese for the "pupil." Place a small piece of red bell pepper on either side of the "pupil" for the "eyelids".