Preheat oven to 350 degrees. In a large bowl, mix cake mix, eggs, butter and water. Blend, stir in mandarin oranges and beat at medium speed until oranges are crushed and well mixed into batter. Pour into greased waxed paper 8-inch pan. When cake is completely cool, prepare icing.
ICING: Mix Cool Whip and drained crushed pineapple and vanilla instant pudding in large bowl until peaks are forms. Leave in refrigerator.