To ingest Alien vs. Predator on its own slimy, divertingly synthetic terms, it helps to forget everything previously known -- and loved -- about the franchise monster aliens who get star billing. The original, terrifying, maxi-toothed 1979 Alien, with her unsightly drool, has little in common with the oh-here-they-come-again mother and hatchlings who stir up trouble in this perfunctory showdown, and the Predator fought by Arnold Schwarzenegger so pre-gubernatorially back in 1987 has been replaced by what appears to be a very middle-aged head-chopper in rubber-tube dreadlocks.
Still, there's pass-the-time fun to be had, of a special FX kind, in the video game-style sequel served up by Paul W. S. Anderson, set 2,000 feet beneath an Antarctic ice cap in a hidden pyramid where Predators have, it turns out, hunted Aliens since time began. It's just the dubious luck of a group of human explorers and treasure hunters that their expedition coincides with the next big A vs. P amazing race.
The face-offs -- and I do mean face-offs -- between megamonsters is pretty standard, goo-on-goo computer-enhanced combat. But the humans are interesting, while they last, if only because Anderson has assembled a strangely cool cast willing to get slimed and say stuff like ''It seems that we are rats in a maze!'' ''Aliens''' Lance Henriksen plays the billionaire adventurer intent on uncovering the pyramid (before he dies of a mysterious billionaire's respiratory disease). His specimen team includes Sanaa Lathan (only recently sparkling in ''Raisin in the Sun'' on Broadway) as ecologist and group leader, ''Trainspotting'''s Ewen Bremner as a geologist (and Scottish comic relief), and ''Under the Tuscan Sun'''s Raoul Bova as the handsome Italian archeologist a girl would most like to get sticky with deep underground.