Preheat your oven to 350°F.
Slice the green onion and set aside.
In a medium bowl, mix together the cream cheese, sour cream, mayonnaise, Worcestershire sauce, lemon juice, and garlic powder until smooth.
Stir in the seafood (crab and shrimp) along with the shredded cheddar.
Transfer the dip mixture to a small oven-safe dish, top with green onions, and bake for 15 minutes until hot and bubbly.