Place cake on platter, slice in 1/2 horizontally. Remove top and set aside.
Place candycanes in lg resealable bag, seal the bag and crush the candy w/ a mallet.
Spread 1/2 the whipped topping on bottom 1/2 of cake. Sprinkle w/1/2 the candy. Replace top of cake and spread remaining whipped topping over cake. Sprinkle w/ remaining candy. Refrigerate until ready to serve.