I created this with a styrofoam cup. I used an exacto knife and cut out sections while still leaving enough support for it to stay standing in its original shape. After I cut out sections I added pieces back in, in different spots. A problem I had when I was making this was getting it to still stand up without pieces. I overcame this by adding in other pieces to give it more support.
If I were to do this again I would mostly likely change what I did by coming up with a plan of what I was going to cut out, instead of just cutting out random pieces.