Prepare sauce: In a medium saucepan over high heat, bring 1/2 cup water to a boil. Add 2 cups of the blueberries; return to a boil. Cook until liquid is released from fruit, about 2 minutes. Meanwhile, combine 1/3 cup of the sugar, the cornstarch and salt in a cup. Add to cooked blueberries, stirring constantly, until sauce thickens, about 1 minute. Spoon into a medium bowl; cover and refrigerate until cold, about 2 hours.

Prepare filling: In a small bowl stir together cream cheese, the remaining 1 tablespoon sugar, and red and yellow food coloring to make orange-colored cream cheese; set aside.

Assemble: Using a serrated knife cut a thin layer off the top and bottom of the pound cake. Cut the pound cake into 4 (1/2-thick) horizontal slices. Working with 1 slice at a time, use a 4-inch bat-shaped cookie cutter to cut out 2 bats. From the same slice, use a 1/2-inch half moon-shaped cutter, to cut out 4 half moons. Repeat with remaining pound cake. Carefully spread 4 bats and 8 moons with cream cheese mixture. Arrange the remaining 1/4 cup blueberries in a single layer over cream cheese, dividing evenly and pressing lightly. Cover with remaining bat and moon shapes forming sandwiches. In a cup combine confectioners sugar and cocoa; through a fine mesh strainer lightly sprinkle over bat and moon sandwiches. Divide blueberry sauce among 4 serving plates; spread to form a "sky background."