Mix cream cheese, mayonnaise, sour cream and butter until smooth. Blend in seasoned salt and paprika. Stir in yellow onions, crab meat, green pepper, and mozzarella cheese. Place in a lightly greased small shallow baking dish and place in a preheated oven at 350 degrees until mixture bubbles, about 10 - 14 minutes. Serve dip with unsalted or very lightly salted corn chips. This appetizer will serve two to three or makes a great light lunch with a crisp salad.