Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine softened cream cheese, sour cream, and half of the Parmesan cheese.
Stir in the chopped spinach, minced garlic, red pepper flakes, and Old Bay seasoning until well incorporated.
Fold in the chopped shrimp and lump crab meat gently to maintain the texture of the seafood.
Season with salt and pepper to taste, then transfer the mixture to a baking dish.
Sprinkle the remaining Parmesan and mozzarella cheese on top of the mixture in the baking dish.
Bake in the preheated oven for 25-30 minutes, or until hot and golden brown on top.
Remove from the oven and let it cool for a few minutes before serving.
Serve warm with your choice of tortilla chips, bread, or fresh veggies.