FILM : Engendered ‘Species’ : XFX in Sun Valley sprinted to create an alien that would attract and repulse viewers.

How do you make millions of people scream?

Steve Johnson needed a few pairs of pantyhose.

No, Johnson’s Sun Valley company, XFX, wasn’t crafting the special effects for “Attack of the Killer Nylons.” But women’s hose did come to the rescue for Johnson while making the alien hybrid for the film “Species,” a Roger Donaldson-directed thriller starring Ben Kingsley, which opens today.

“One of our major hurdles was how to keep her mobile but translucent,” Johnson said of “Species” creature star Sil, a quick-growing, quick-killing lab experiment created by splicing together DNA from an alien and a human female. Sil was designed by H. R. Giger, who won an Academy Award for his design of the “Alien” creature.

To build a creature that allowed light to pass through her interior, Johnson’s special-effects team labored for weeks to make an animatronic puppet whose legs, arms, chest and head were covered with a clear plastic shell.

With only a few weeks left before shooting, the team was still struggling to find a translucent but flexible membrane to cover Sil’s torso and neck.

“I was racking my brain at home, in the shower, in my sleep, everywhere,” Johnson said. “Then it hit me: ladies’ pantyhose. I bought a bunch of hose on the way to work. We put it on Sil and it worked perfectly. It’s incredibly mobile and doesn’t wrinkle.”

Welcome to the madcap, macabre world of monster-making, where some pantyhose and a lot of ingenuity can separate the special-effects pros from the rest of the pack.

In a marathon monster-making session, Johnson and his crew took two pen-and-ink drawings by Giger and transformed them into a slashing, animatronic puppet.

As the animatronic wizard behind “Poltergeist II,” “The Stand” and “The Abyss,” Johnson and his crew were no strangers to creature features.

But this film presented a horrifying task, even for Johnson: Whereas studios normally grant about 24 weeks to build a puppet, delays in choosing a special-effects crew had slashed the time to about half that. Several other special-effects teams had tried to please Giger, but couldn’t.

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“We had so little time,” said XFX art director Bill Corso. “We only had 12 or 13 weeks before they started shooting.”

Johnson’s team began its daunting task armed only with Giger’s sketches of Sil’s front and back. Giger had drawn a willowy, curvaceous form with hair like Medusa, clawed hands, spikes in her back and the face of a cadaver. Internally, the creature’s organs were visible through translucent skin.

“It was meant to draw your eye to the creature at the same time you are repulsed by it,” said Joe Fordham, XFX’s production coordinator.

Using Giger’s two drawings, Corso made sketch after sketch, from every angle, until the creature began to take on a three-dimensional form in Johnson’s eyes. To ensure that the creature’s feminine curves would stand out amid its horrific countenance, Corso brought in a model who posed in leotards.

Within a week of receiving Giger’s sketches, Johnson’s team began sculpting a seven-foot-tall clay model of Sil. Johnson stayed in constant touch with Giger to ensure his satisfaction, faxing sketches and sending videotapes to Giger’s home in Switzerland.

Often, Johnson’s team had to find the fine line that satisfied everyone.

“The producers and directors would come in and say, ‘She needs to be more masculine. Beef her up,’ ” Corso said. “Then Giger would say, ‘She’s not sexy enough.’ ”

At least a dozen other “Species” effects the XFX team also was making chewed up time. These included an amoeba-like creature, a tentacled alien, a chrysalis, an exploding head and six mechanical rubber arms with spring-loaded elbows.

Within three weeks of starting the project, the XFX team began making a silicone mold of Sil. From these molds, transparent pieces of the creature’s head, legs and arms were made.

Then Johnson’s group tackled the task of Sil’s mechanical inner structure.

During the next six weeks, XFX technicians developed four main animatronic puppets--one with a simulated birthing ability, another for stunts, a third for pyrotechnics and one “hero” version with snakelike breasts, nictitating eyes and writhing, tentacle-like hair.

For non-puppet scenes, Johnson’s crew also completed a rubber body suit, briefly worn by an actress, and a model digitized by a Utah firm to create a computer-generated image.

The XFX crew did get a bit of a break timewise by not having to conceal some of the innards of the biomechanical creature.

“The whole interior of her neck is an actual ball in a socket with cables,” Corso said. “You can actually see it, but you’re not sure what it is.”

Finally, the mechanized inner parts were covered with the translucent outer shell--including Johnson’s nylon torso--to finish the creature.

And just in time. Johnson’s puppets barely made it to the first day of shooting. “The paint was still drying when we put her in the hot tub” for the first scene, Corso said.

The “Species” project was the most work ever done by XFX in the shortest amount of time, Johnson said.

“The greatest challenge was getting Giger’s design across,” Johnson said. “It can be so difficult, that you can just throw up your arms.”

But the frustrations paid off. After seeing the rough cuts of Sil in action, Giger sent the XFX team a note.

“You made me very happy,” Giger wrote. “For this, you should get an Oscar, at least.”