Prepare cake mix using box directions, substituting part of the water with pineapple juice. Pour into greased 9×13 pan and bake at 350°F (175°C) until golden and toothpick comes out clean.
Cool cake completely.
In a large bowl, whisk coconut and vanilla pudding mixes with cold milk for 2–3 minutes until thickened.
Stir in crushed pineapple until evenly combined.
Spread pudding mixture evenly over cooled cake.
Spread whipped topping over pudding layer and sprinkle with shredded coconut.
Garnish with maraschino cherries or pineapple slices.
Chill for at least 2 hours before serving.
