In a mixing bowl, combine fresh spinach, cream cheese, shredded mozzarella, sour cream, Parmesan cheese, garlic powder, onion powder, salt, and black pepper. Mix until well combined.
Take a mozzarella stick, spoon some spinach mixture on top, and wrap it around the stick. Repeat with all sticks.
Dredge each wrapped stick in flour, dip in beaten eggs, and coat with breadcrumbs.
Heat vegetable oil in a frying pan. Fry the sticks until golden brown on all sides. Drain on paper towels.