I'm going to make some fake eye balls for my mother's Halloween dinner this Sunday, for a bentos this week, and for our smaller, but scarier dinner on Halloween night.
One idea I had was using Daifuku or sweet red bean filled mochi. The red filling with the mushy sweet outside would be a wonderful treat, and I could try using food coloring to paint on details (if it works). Dango (boiled mochi balls without fillings) was another option.
The other idea I had was for a more savory treat. My husband and I made some "Go Bulgogi", as he likes to call it. Basically, you make bulgogi (korean grilled marinated beef) using ground beef instead of strips. This made it easy to stuff into Onigiri and was darned tasty. So, for the savory Zombie Eyes, we were thinking about making the "Go Bulgogi" into meat balls before cooking. Then we would wrap the cooked meatballs in the mochi dough much like the red bean paste is wrapped in the mochi dough, though I'm not sure if I would use a plain flavor or a sweet. (I think the sweet mochi casing would be a nice compliment to the savory sweet meat filling!)
Here's one sweet recipe my mother sent me. It looks good and was very different than what I was originally going to do. Enjoy!