Deep into Richard Kelly's miasmic 160-minute fantasy "Southland Tales," an actor who used to call himself "The Rock" places a gun at his temple and says, "I could pull the trigger right now and this whole nightmare will be over," and every impulse screams: "Do it!"

It comes too late, however, as the will to live is lost in the first reel when ex-Rock Dwayne Johnson, playing a $20-million-a-film movie star, tells of an infant that has not had a bowel movement in six days and warns that a thermonuclear baby fart could blow up the world.

Written and directed by Richard Kelly and employing most of the creative team of his 2001 film "Donnie Darko," the picture was conceived in tandem with three graphic novels that tell the story leading up to the end-of-the-world scenario depicted in "Southland Tales."

The film strives to rank alongside such classics as "Brazil" and "Blade Runner" but falls more into the category of "Mars Attacks!" and "1941," and boxoffice potential will rely on very tolerant young audiences.

Kelly, cinematographer Steven Poster, production designer Alexander Hammond and costumer April Ferry succeed in putting some impressive images on the screen as the city of Los Angeles sees its final days. But the English term "shambolic" best describes a slow-paced, bloated and self-indulgent picture that combines science fiction, sophomoric humor and grisly violence soaked in a music-video sensibility.

The opening sequence shows a nuclear mushroom cloud bursting over Abilene, Texas, but the after-effects aren't too bad because by 2008, the Venice natives in Los Angeles remain pretty much as they've always been.

A new fuel called "fluid karma," using hydroelectric power drawn from the ocean, promises to save the future, though scientists, corporations, the Pentagon and big government inevitably start to fight over it.

Several factions want in on the action, including a Marxist group, a porn actress bent on blackmail and assorted gun-toting freaks. Somewhere at the heart of things is the movie star who has written a screenplay detailing a geological phenomenon that he imagined but turns out to be actually happening. It has something to do with a breach in the space/time continuum, the usual stuff.

There's also a police officer who exists in two forms (both played by Seann William Scott), and it becomes important that the two incarnations meet. Or don't meet, something like that. Not that it matters. Sequences exist for themselves, and few would be missed, though one or two are quite entertaining. Justin Timberlake, who doesn't have much to do as some kind of soldier, features in a bizarre dance number to the fabulous Killers track "All These Things That I've Done" that has MTV rotation written all over it.

Familiar faces including John Larroquette, Jon Lovitz, Miranda Richardson and unbilled Janeane Garofalo pop up here and there to no great effect. Wallace Shawn and Zelda Rubinstein are on hand, as you would expect, as mad scientists.

Scott, Johnson and Sarah Michelle Gellar, as the porn star, do their best with the lame material, but it's uphill work. There was more fun and greater character development in "Starship Troopers."

SOUTHLAND TALES
Universal Pictures and Cherry Road Films

A Cherry Road/Darko Entertainment and MHF Zweite Academy Film production

Credits: Writer-director: Richard Kelly; Producers: Sean McKittrick, Bo Hyde, Kendall Morgan, Matthew Rhodes; Executive producers: Bill Johnson, Jim Seibel, Oliver Hengst, Katrina K. Hyde, Judd Payne, Tedd Hamm; Director of photography: Steven Poster; Production designer: Alexander Hammond; Editor: Sam Bauer; Music: Moby.

Cast: Boxer Santaros: Dwayne "The Rock" Johnson; Roland Taverner: Seann William Scott; Krysta: Sarah Michelle Gellar; Dr. Soberin Exx: Curtis Armstrong; Brandt Huntington: Joe Campana; Cyndi Pinziki: Nora Dunn; Starla Von Luft: Michele Durrett; Dr. Inga Von Westphalen/Marion Card: Beth Grant; Dion: Wood Harris; Vaughn Smallhouse: John Larrroquette; Serpentine: Bai Ling; Bart Bookman: Jon Lovitz; Madeline Frost Santaros: Mandy Moore; Sen. Bobby Frost: Holmes Osborne; Zora Carmichaels: Cheri Oteri; Veronica Mung/Dream: Amy Poehler; Martin Kefauver: Lou Taylor Pucci; Nana Mae Frost: Miranda Richardson; Shoshana: Jill Ritchie; Dr. Katarina Kuntzler: Zelda Rubinstein; Fortunio Balducci: Will Sasso; Baron Vin Westphalen: Wallace Shawn; Hideo Takehashi: Sab Shimono; Simon Theory: Kevin Smith.