Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper.
In a large mixing bowl, combine the softened cream cheese, shredded cheddar cheese, Worcestershire sauce, garlic powder, Old Bay seasoning, and black pepper. Mix until well combined.
Gently fold in the lump crab meat and green onions, being careful not to break up the crab too much.
In a separate small bowl, mix the breadcrumbs, mayonnaise, and lemon juice until combined.
Using your hands, form the crab mixture into small balls, about 1 to 1.5 inches in diameter. Place them on the prepared baking sheet.
Top each crab ball with a spoonful of the breadcrumb mixture, pressing it gently to adhere.
Bake in the preheated oven for 20-25 minutes, or until the tops are golden brown and the crab bombs are heated through.
Remove from the oven and let cool for a few minutes before serving. Garnish with fresh parsley if desired.