Pig Lickin' Cake

1 (18 1/2 ounce) box Duncan Hines?
    yellow butter cake mix
3/4 cup vegetable oil
4 eggs
1 (11 ounce) can mandarin oranges and juice

Beat all ingredients together for 4 minutes. Bake at 350 degrees F in 3 layers for 20 to 25 minutes. The layers will be thin. This cake is best done in 3 layers, but it may be baked in only 2 layers or in a tube pan; bake the cake longer, however. Cool, then ice.

Icing
1 small box instant vanilla  pudding mix
1 (15 1/2 ounce) can crushed pineapple, drained
1 (9 ounce) container frozen whipped topping, thawed

Mix all ingredients by hand. Do not use an electric mixer. Iced cake is best kept refrigerated, and it keeps well.