Gross and edible... the jello brain. We tried different colors and presentations. The blue brain was lit from a tube/stand below the glass plate. The pool underneath the brain is a nice effect, but is indeed slightly melted jello... beware the hot light bulb! A bit of milk added to the liquid of the jello mix gives the brain more opaqueness.
The year we planned the Mad Scientist Lab, we went looking for this jello mold, and found it at a local toy shop. I've seen them online as well.
We found additional edible body parts by poking around at various discount stores. Bags of foil wrapped chocolate eyes, ears, etc. filled a small plastic cauldron.
Canning jars, glass beakers and stainless steel trays make nice serving pieces. And a liberal sprinkling of rubber rats around the food didn't seem to scare off snackers! American Science and Surplus has been a favorite and affordable prop supplier for years for lab equipment and more. Their collection of odds and ends is inspiring!