Last night I came up with an idea for a cake I am making and realized I needed some Rice Krispy Treats in order to give bulk but not a lot of weight to my fondant creation. I did not have any rice cereal in the house or premade RKTs. So, I improvised with crushing up some Cheerios and making the recipe the same way. Not too bad but not great either.

So, I was wondering what else can be used in this situation?

If you're not picky about it being edible, you could use styrofoam. I wonder how popcorn would do? It's pretty light. You'd probably want to pop it without salt or butter, though. Or maybe not, given the popularity of those salty caramel mixtures lately!