Becoming a vampire in the Buffy the Vampire Slayer universe requires making and wearing prosthetics. Imgur user mignolafan, a.k.a. Zach Jones, made a custom piece for his friend to wear to Calgary Comic and Entertainment Expo so he could become Spike. He started by molding his friend’s face so the prosthetic would fit properly. He says:
I used alginate to pull a highly detailed mold, and encased that in a plaster bandage mother mold to help hold rigidity. I made the casting in the photo from ultra-cal 30, an industrial plaster. The longer you mix the plaster the harder it will set. Burlap strips were used with the plaster to strengthen the final casting and bulk up the size.
Then he used plasticine to get the basic forms of the prosthetic in place. You can see a couple of in progress pictures below.