The Cacodemon eyeball was very fun and challenging to make. First, I made a simple silicone cup mold of the acrylic sphere I used for the eye. Then I cast a resin copy and ground a flat area for the pupil (see pic 1 below). Next, I took some Monster clay and carefully sculpted a gross pupil, referencing cat eyes. These pupils essentially work like sphincter muscles (see pic 2). Once the sculpt was complete, I molded it in a silicone cup mold, then cast an eye using a phosphorescent yellow pigment. Carefully, I painted it green but made sure that the yellow would still shown through. In the fourth image below, check out the painted eye beneath an LED light pad. Finally, I put that painted eye into the first mold of the acrylic sphere and filled it with water clear translucent resin to create the cornea over the pupil (see pic 3). My first attempt at this failed. The water clear resin I used proved to be unstable with the thin layer I was making over the pupil. All the eye parts were cast in my pressure pot to reduce air bubbles. This pressure pot with 60 lbs of air pressure in it, shrinks the bubbles making them invisible to the naked eye until the resin sets up which is usually in about 2-4 hours. This worked fantastically at first, but about a day after the eye was finished, the water-clear resin started to bubble and delaminate from the pupil. The resin was not completely set up. To resolve this I kept the mold in the pressure pot for 2 days to make sure the resin set up properly. In retrospect, I should have purchased newer clear resin.