Poor Ah-nuld. Once, as Conan, he drove his enemies into the sea while listening to the lamentations of their women. Then, as the mighty Terminator, he came back, exactly as he promised, and laid waste to all who rose against him, or just happened to be in the room.

Now, in "End of Days," he's morphed into a somewhat less intimidating figure: He is the world's most heavily armed chaperon.

Yes! His latest billion-dollar blow-'em-up blows up lots of things real good, but mainly it's about Ah-nuld and his dozens of Glock pistols (Austrian guns for an Austrian guy, no?) trying to stop two adults from having sex! In the old Hollywood, this role would have been played by a starchy Republican spinster. Where is Margaret Hamilton when we need her? What about Eve Arden? Roz Russell, phone your agent.

All these ladies would have had more luck than Ah-nuld. They could wither with a glance; it takes him several high-cap mags to achieve the same effect, and to what end, really? I mean, it's the '90s. When people want to do It, they do It. So what if the world ends in consequence?

The movie is part action thriller, part ecclesiastical meditation but mostly new rules of dating for the millennium. No. 1 would be: "When the Devil asks you to dance, it's probably a good idea to say no, but be nice, you may have to network with him sometime in your career." When it's not focused on such matters, it's just another one of those standard hyperventilating, pulsating masses of unformed energy and seething twitching anger that are so damned busy they're almost entertaining. Too bad this isn't. The director, Peter Hyams, seems not to have read the script; possibly he was too busy fiddling with camera stops (he is, famously, his own cinematographer, and as a director he's a very fine cinematographer). But if you want to see Ah-nuld actually--oof! grunt! argh!--act, here's your chance. He even has a go at a weeping jag.

The story, to the extent that it can be penetrated, goes a little something like this: Every thousand years, Himself (also known as Scratch, Mephistopheles, Mr. Nibbs, Satan, dat ol' debil, der Teufel selbst, Ebon and so forth and so on) returns to Earth for a few days. What's he want? He wants what any sailor wants. He wants a date, see?

The deal is, he's looking for Rosemary's baby, grown up to be a cool chick (played by Robin Tunney). She's the One because she was born under the right star formation and has a birthmark like a horseshoe on her arm. Only she doesn't know she's the One. She just wants to be a good girl. But if the Devil can score with her, his imprisonment is over and he will rule. It says so, either in the Bible or the script, I forget which.

Schwarzenegger, as some sort of dimly described, patently unconvincing professional security guard, is minding his business when somebody takes a shot at his client. After seven minutes of action sequence, Ah-nuld corrals the shooter who turns out to be--this is the kind of movie it is--a priest who's cut out his own tongue with a pruning hook. Did the Devil make him do it? No, he was trying to do it to the Devil--that is, the client.

Actually, it's just Gabriel Byrne, who went to the bathroom in a restaurant and there had a nasty encounter in the men's room with the opaque specter representing the Prince of Darkness. We've just seen this smear of blur spring from the underground, and I don't mean the subway. Memo to self: Always stay out of men's rooms in New York. You never know what you're going to run into.

Freed and wearing Byrne like a suit of clothes, the Devil begins to roam, getting ready for his prom, which just happens to be from 11 p.m. to midnight Dec. 31, 1999, to connect the film, in the spirit of millennium angst, with all those alarming magazine covers. Byrne is probably the movie's best asset. Darkly handsome with a boulevardier's rogue charm, he swaggers through midtown like Donald Trump under a dye job, except that he has better taste in clothes. When people disappoint him, he orders the universe to crush them and of course that's an amusing power fantasy: Imagine walking down the street, and if someone displeased you by dress or deportment, you could simply erase him with a nod! Sounds like fun to me.

Alas, the virgin in question would prefer not to give it up to a guy with hoofs, even if her own stepmother sees a future in evil and wants the girl to marry above her station. Then, the church is divided into factions, one of which wants to smother her with piety under the dreary ministrations of Father Rod Steiger, and another of which wants to kill her to make certain the infernal congress never occurs. It's hard to tell which is more appalling, but guys keep coming out of the woodwork and Ah-nuld and his parter, eternal wiseguy-sidekick Kevin Pollak, keep blowing them off the surface of the planet.

The movie has one effective scene: To dissuade the hulky bodyguard from protecting the chosen One, the Devil tempts him. He offers Ah-nuld what God cannot: to restore what God has taken, that is, his lost wife and child, murdered in retaliation for his duties as a police officer. It's like Christ on the mountain, being offered the world (Ah-nuld as the new, very buff Jesus is a line the movie follows in other ways, too, including an ersatz Crucifixion). It just barely works, and when Ah-nuld cries in anguish, you have to call him Arnold, because, yes, that is indeed acting, not flexing.

As I say: It's silly, loud, brutal and way too long, and, worse, the action sequences (of which there are many) feel generic, over-reliant on flaming clouds of propane for oomph. And I think the movie fails in two smaller ways in terms of its own weird universe: One, at a certain point it replaces the silky, gangsterlike Byrne with a rough beast built of fire, for which we feel nothing. And two, it never shows us a vision of the end of days, so we never know what's at stake. When Mr. Beelzebub takes over, how would it be different from now? And . . . would we even notice?

End of Days, at area theaters, is 120 minutes longer than the millennium and is rated R for extreme violence and gore.