Heat oven to 350°F. Grease 13x9x2-inch baking pan.
Beat eggs in medium bowl; add brown sugar, pumpkin and oil, beating until well blended. Stir together flour, baking powder, baking soda and pumpkin pie spice in large bowl; add egg mixture, beating until smooth. Stir in toffee bits. Pour into prepared pan.
Bake 25 to 30 minutes or until wooden pick inserted in center of cake comes out almost clean. Cool completely in pan on wire rack.
Combine water and 3 to 4 drops food color in small jar with lid or re-sealable food storage bag. Add coconut; shake until coconut is evenly colored. Set aside.
Remove wrappers from candies. Chop and place 4 candies in small microwave-safe bowl. Microwave at MEDIUM (50%) 1 minute; stir. If necessary, microwave at MEDIUM an additional 10 seconds at a time, stirring after each heating, until candy is melted and smooth when stirred. Transfer to heavy-duty (freezer) food storage bag and cut off one bag corner about 1/4 inch from tip. To make pumpkins, place dot of melted candy on bottom of one pumpkin spice candy; press bottom of another candy to it. Allow to firm. Melt chocolate chips and place in pastry bag with small tip. Pipe facial features onto candy pieces to resemble pumpkin faces; set aside.
Prepare CREAM CHEESE FROSTING. Remove 1/2 cup frosting; tint with food color to desired shade of green. Frost cake with remaining frosting. Sprinkle frosting with tinted coconut and place "pumpkins" on "patch". Add piped green frosting to form leaves. Makes 24 bars.
CREAM CHEESE FROSTING:
Beat 2 packages (3 oz. each) softened cream cheese and 1/2 cup (1 stick) softened butter or margarine in large bowl until well blended. Gradually add 4 cups powdered sugar and 2 teaspoons vanilla extract, beating to spreading consistency. Makes 3 cups frosting.