as well as a technical touch. For one scene in "Let Me In," a murder victim needed to be hanging upside down from a tree. Flipping upside down completely changes the way gravity acts on a face, Clement said, so he and his team got creative: They had their actor get on an inversion table, a piece of equipment used to relieve back pain by turning a person upside down.

The team placed the silicon, waited for it to gel, and then, as it was still slightly soft, flipped their silicone-coated model at a 45-degree angle. The resulting cast captured the upside-down effect perfectly, Clement said.

"It didn't look correct when you looked at it right-side up, but when you looked at it upside down, it was quite convincing," hesaid.

Clement isn't the only special-effects expert who repurposes materials and techniques for the perfect onscreen look. Mark Coulier, the director of Coulier Creatures and winner of an Academy Award for his work on 2011's "The Iron Lady," was responsible for many of the effects seen in the "Harry Potter" films. One particular challenge was a scene in which Daniel Radcliffe, playing Harry, sprouted webbed fingers for an underwater swim. Prosthetic webbing couldn't stand up against the force of the water, Coulier said, and whole-handed gloves just looked weird and bulky.

"We ended up covering his whole arm with a woman's stocking and we stuck the stocking together between his fingers and painted silicone on," Coulier told LiveScience.

Printing monsters

The digital world has changed the world of practical effects — there