Bake cake mix in a 13x9" pan according to package directions. In medium saucepan, combine pineapple with it's juice and sugar; cook over medium heat, stirring occasionally, until thick and syrupy, about 20 minutes. When cake is done, remove from oven and pierce top with a fork at 1" intervals. Pour on pineapple mixture and spread evenly over cake. Cool completely. In a medium bowl, combine pudding mix with milk; Blend until thick. Spread over cake. In a medium bowl, beat cream until soft peaks form. Add powdered sugar and vanilla; continue beating until stiff. Spread over cake. Refrigerate 24 hours. Before serving, sprinkle with coconut.
