PASADENA, Texas -- Things took a turn at a graduation party when a family learned that the cake they purchased wasn't chocolate or vanilla - but Styrofoam.Nellie Flores told ABC7's sister station KTRK-TV that she and her sister, Marsy, ordered a graduation cake from a Walmart in Pasadena, Texas, last week.The two-tier cake was for Marsy's daughter who was having a graduation party.When it came time to pick up the cake on Thursday, Nellie and Marsy learned that it had not been made.They said a Walmart store manager told them to choose any cake from the ones that were ready to go. They took one of the cakes and put a photo on it.Everything was fine until it was time to cut the cake. That's when they discovered it was made of Styrofoam.The family said they felt humiliated and returned to the Walmart, where a manager gave them a $60 gift card for the value of the cake, in addition to another gift card and a free cake (not Styrofoam).Walmart released the following statement: