Boil shrimp in water according to crab boil directions. (Crab boil is found in the spice section of the grocery store.) Peel, devein and chop shrimp. Use a hand mixer to blend cream cheese, mayonnaise and Thousand Island dressing. Stir in shrimp, green onion and grated onion, Tabasco sauce, seasoned salt and horseradish. Serve with crackers or vegetables. Make at least 8 hours ahead of serving time so flavors blend.