Preheat the oven to 400 degrees. In a mixing bowl, combine the ground turkey, breadcrumbs, egg, garlic powder, oregano, salt, and black pepper. Mix until evenly blended.
Divide the mixture into 8 equal portions and roll each into a meatball. Place the meatballs on a baking sheet lined with parchment paper.
Bake the meatballs for 18 to 20 minutes until they reach an internal temperature of 165 degrees. Remove the sheet from the oven.
Place one mozzarella slice on top of each meatball. Add one olive round in the center of each slice to form the eyeball. Return the sheet to the oven for 2 to 3 minutes until the cheese melts.
Warm the marinara sauce in a small saucepan over low heat. Spread a spoonful of sauce inside each slider bun, add one meatball, and close the bun.