PREHEAT oven to 350°F. Grease and flour 2 (8- or 9-inch) round cake pans. Line bottoms of pans with wax paper. Set aside. Place cake mix, cocoa, eggs, water and dressing in large bowl of electric mixer. Beat on low speed 30 seconds, stopping frequently to scrape bottom and side of bowl. Beat on medium speed 2 minutes. Pour evenly into prepared pans.
BAKE 30 to 35 minutes or until toothpick inserted in centers comes out clean. Cool 10 minutes; remove from pans. Immediately remove wax paper. Cool completely on wire racks.
CUT 2 oblong ovals from each side of 1 of the cake layers for the bunny's ears. Reserve remaining cake piece for the bow tie. Arrange cake pieces and the whole cake layer on large serving platter or cutting board covered with colored plastic wrap to resemble the bunny's head. Spread with the whipped topping. Decorate with candies. Store in refrigerator.