This dog cake (for humans) features a collar made from green sour gummies and candy-coated chocolate.
Trim blondie to 6-inch square; repeat with brownie. Cut out small bones from scraps with dog-bone-shape cutter.
Coat a large dog-shape cutter with cooking spray. Cut out a dog from center of each 6-inch square. Carefully place brownie dog into cutout in blondie, and blondie dog into cutout in brownie. Spread brownie with frosting. Top with blondie. Decorate with green sour gummies and candy-coated chocolate for collar. Refrigerate until set, 20 minutes. Serve with ice cream and dog bones.