Lay each banana curve side down on 12-inch piece of aluminum foil. Wrap foil around each banana, leaving tops exposed. Arrange bananas in single layer in 13x9-inch baking dish.
Cut banana peel lengthwise about ½-inch deep, leaving ½ inch at both ends. Drizzle with caramel dip. Arrange strawberry, marshmallows, blueberries, blackberries on top. Repeat with remaining bananas.
Bake 10-15 minutes, or until bananas begin to blacken and marshmallows melt.