Despite the implication of the Alien3 logo, there's really only one creature running loose on the planet Fiorina 161. But special-creature-effects artists Alec Gillis and Tom Woodruff Jr., who together form Amalgamated Dynamics, Inc. (ADI), had to build a virtual army of the beasts to portray the monster as it changes form throughout the film.
''I've never seen one like this before,'' Sigourney Weaver's Ripley says early on. ''It moves differently.'' In previous Alien films, the creature always gestated inside a human being; this time a dog is the unfortunate host, and the creature that emerges shares some of the dog's characteristics. The first form of the alien to make a (thankfully fleeting) appearance, dubbed the ''Dogburster'' by Gillis and Woodruff, is essentially a hand puppet thrust through the chest of a mechanical rottweiler.
For the next shot, showing the newborn alien clambering unsteadily to its four feet, ADI constructed a large, cable-controlled puppet, its nylon skin slathered with a slimy substance called methylcellulose (the same stuff used to thicken fast-food milkshakes). The ADI crew called this version the ''Bambi- burster.'' ''Director David Fincher wanted the women in the audience to go 'aww' when it first tries to stand up,'' says Gillis, ''and the next time you see it, it's spitting acid.''
The ''Acidspitter,'' a sort of adolescent phase of the alien that squirts acid blood, is another cable-controlled puppet, mounted on Woodruff's arm. It makes only one appearance, rearing up at a prisoner who peers into a vent where it's molting.
For the adult alien, Gillis and Woodruff, both 33, wanted to create a creature more faithful to the original drawings of H.R. Giger, the Swiss illustrator who designed the look of the first film. Also taking into account Fincher's directive that the creature should be ''a freight train with teeth,'' the FX team sought to combine the features of a predatory cat with an insect to create a four-legged alien that could run up walls and across ceilings. (One of the film's more interesting innovations is showing the action from the creature's point of view as it scampers, often upside down, after its prey.)
The new alien is more wasp-waisted and sleek than its predecessors, and the blank, porpoise-like skull-dome has been restored. ''One of the scariest things is that it has no eyes, yet it can find you,'' says Woodruff, who, with Gillis, honed his technique on the giant worm in Tremors. One new detail was lips. ''When the lips are closed,'' Gillis says, ''there's more of a shock when they open up and you see silver teeth. They also look like they could kiss you.''
ADI constructed a few heads for the alien, each customized for a particular task. The ''hero head,'' designed for close-ups, could pull its lips back in a snarl. The ''tongue head,'' operated by Woodruff's hand inside its neck, could open its jaws and extend its fanged tongue. One head had a pneumatic plunger to fire a hard tongue through a model of a character's head.
Despite all the technological innovations, though, the adult alien ultimately comes down to a man in a rubber suit-an approach that hasn't changed much since 1954's The Creature From the Black Lagoon. Woodruff the man would climb into the outfit, and technicians would affix whichever head was needed. ''I don't mind the feeling of fiberglass,'' he says. ''We didn't want to bulk up the suit with buckles or a fly, so I got glued into it and stayed there all day. I drank just enough liquid to be safe.'' In an age of 70 mm technology and computer-generated effects, it's nice to know some things are still done the old-fashioned way.