Italian Shrimp-Spaghetti Casserole

1/2 pound butter
1 onion, chopped
2 cloves garlic, chopped
1/2 bell pepper
2 tablespoons crab boil
4 pounds shrimp
1/2 cup parsley, chopped
1 tablespoon garlic powder
2 bay leaves
1 egg
1 pound spaghetti or other pasta Parmesan cheese

Melt butter. Saut