Remove cakes from the pans. Use a serrated knife to cut the tops off each layer of cake.
Put the first layer down on a cake plate. Place a 4" cookie cutter in the middle and spread frosting around the outside.
Using the 4" cookie cutter, create a hole in the middle of the next layer. Place it on top of the first layer and add another layer of frosting.
Repeat with the third layer.
Add assorted candy into the hole. Make sure you fill it all the way up to the top.
Frost the top portion of the cake and add the final layer (bottom side up).
Give the entire cake a nice crumb coat and set it in the fridge for at least 30 minutes.
Once the cake is cooled, prepare a piping bag with a colorful frosting and a ribbon tip.
With the larger side of the ribbon tip facing down, pipe all the way around the cake. Once you have gone all the way around, start 1/4" above the first later and do a second layer.
Alternate colors until you reach the top.
With the larger side facing out, pipe around the top of the cake.
Alternate colors until you reach the center.
Add a DIY cake topper.