Inspired by different sources online, I managed to make a convincing Residents Eyeball.
First I took a beachball, around 14-15 inches and used it as a base for paper mache. I applied 3 or 4 layers of newspaper, and then two layers of computer paper. (Also make sure to coat the beachball in vassaline so that paper mache won’t stick to it.) Afterwards I cut out a hole for the pupil, then I painted the whole thing with two coats of white acrylic paint; then I painted the Iris with one coat of three different shades of blue. The nylon for the pupil was hotglued inside the eye itself. The veins were made with caulk and painted crimson. (I also recommend attatching a helmet or hard hat inside the eye to insure stability) The top hat was made out of cardboard and then layered in rubber seamless tape.(WARNING: The top hat is heavy.) The top hat was then hotglued.
I hope this helps, there aren’t many thorough instructions online, so this my best attempt to add to the pile.