I made this Tinkerbell birthday cake using rice Krispies. I sculpted it to my liking and then made the icing coat. I then made marshmallow fondant and had fun making all the different colors. I then applied the fondant according to the most common colors needed for Tinkerbell. I cut out leaves for her dress and it turned out great.
I found that sculpturing the rice krispies at room temp was better for me since it keeps it shape. When it was frozen and began to defrost, it started to lose its shape. Hope this helps!! Enjoy!