Can't two undead, teenager-hating killing machines just get along? Apparently not. But you can hardly blame the razor-fingered madman from ''A Nightmare on Elm Street'' and the hockey-masked cutup from ''Friday the 13th'' for being cranky: It's taken New Line 11 years to bring their matchup to the big screen. After buying the ''Friday'' rights from Paramount in 1992 (and teasing the showdown in 1993's ''Jason Goes to Hell''), the studio had a horrific time developing a workable script. The problem? ''Finding a story line that puts these two together without spending three hours,'' says director Ronny Yu. Seven screenwriters later, we open on Elm Street, where kids are being drugged by their parents with a dream suppressant. A powerless Freddy rouses Jason from his between-movies slumber and sics him on his old hood to stir up some fear -- and, he hopes, a new generation of nightmares. Surprise -- the partnership doesn't go well. ''Freddy is like a puppet master who loses control,'' says Robert Englund, who plays Freddy. ''Jason can't stop -- he's killing my victims!''
Caught in the middle of the freakish feud, Elm Street's youths (Monica Keena, Jason Ritter, and Destiny's Child singer Kelly Rowland) pit Freddy against Jason (Ken Kirzinger) and watch them hack the holy hell out of each other. ''I call it 'The Four Fingers of Death Versus the Machete,''' says Yu, who spruced up another fading horror franchise with 1998's ''Bride of Chucky.'' But he'd rather die than reveal which monster takes the title: ''Jason has the physique, and Freddy has the brains.''