They Live is a classic sci-fi horror film, and though I’ve only seen it once, I’ll never forget the look of the aliens. Their skulll-like faces are stuck in my brain, and Instructables user Pris Nexus 6 created some masks that capture the creepy essence of their visage perfectly. She shared the tutorial a couple of years ago and rather than sculpting the mask from scratch and casting it, she cleverly used existing plastic masks and Model Magic air dry clay to make the alien faces.
The blank mask (pictured below) is covered with the clay as a foundation. Using hot glue, she combined that mask with some scary teeth from a plastic demon/skeleton mask. Then:
Once the glue has dried, take some more model magic and blend the mouth part into the mask. Then you can begin adding some depth to the mask to make it look more skeletal. Create deep eye sockets that blend into the brow and parts of the cheeks. Leave gaps in this layer so the previous model magic layer you made will poke through. It will look like flesh tissue poking through a skull.
You can see a photo showing the combined masks below.
Get step by step guidance and photos at Instructables.