For a class last semester I tried to make a record by carving into wax, then making a mold of it and trying to see if it would play back. I went through a lot of materials before just choosing plaster as my final mold. The record didn't really work out but it was interested learning experience sense I had never made a mold before. One material I strongly considered was chocolate. To bad I didn't use it.
plaster cast (I made another one that was not cracked)