It is a cold, cloudy and generally cheerless night in downtown Detroit. But for a breif moment, from the sidewalk outside St. Andrew's Hall, you can actually see a full moon -- the bright white flash of 16-year-old silverchair drummer Ben Gillies' naked ass stuffed through an open tour bus window. Gillies' vertical smile is greeted with delighted shrieks and approveing hoots frome the shivering teenage girls and sweat-drenched mosher dudes who have been clustered around the bus since silverchair wrapped up their feedback-laden encore of "Isreal's Son" nearly an hour ago, but that's nothing compared to the celebratory testosterone now raging inside the vehicle. "All right! Way to go, Gillies! The big brown eye!" raves the band's 16-year-old singer and guitarist, Daniel Johns. he's still breathless from the Austrailian trio's dash from the St.Andrew's backstage door, but his deceptively angelic features are bright with impish glee. Bassist Chris Joannou, who is also 16 and has his long , curly brown hair tucked up under a wool cap emblazoned with the logo of the band Korn, doubles over with laughter. The band's manager, John Watson, just rolls his eyes in bemused resignation while David Gillies, Ben's father , is spared of the entire experience. He and the other silverchair dads, Greg Johns and David Joannou, are still in the venue, packing up the band's gear. When they accomapany their sons on tour, the elders double as guardians and roadies. "Ok, who's gonna give me $10 for that?" the younger Gillies cackles, pulling his caboose out of the forsty night air and hiking up his sweatpants. Nobody ponies up, but he doesn't need the money anyway. silverchair's debut album, "Frogstomp", a youthful blast of wham and commercial riff-smarts, has sold more than 1 million copies n the United States since it was released here in June 1995. Back in Austrailia, the LP has gone triple platinum (210,000 copies) while its signature hit, "Tomorrow," ranks as that country's fourth best-selling single ever.

By the time Frogstomp runs its chart course, Johns, Gillies, and Joannou- all born to hard-working, middle-class families in the Australian coastal city of Newcastle--will have earned in the neighborhood of 1 million dollars apiece (safely held in trust accounts now being set up). Not bad for three high schoolers who got their big break only 20 months ago by winning a small-time demo-tape contest run by an Australian TV show.

But for silverchair, all confessed adrenaline junkies, a good adolescent prank is truly its own reward. Like the wild dressing room food fight (Chinese takeout) the boys had at Roseland, in New York. Or the birthday present they sent to Watson last year --- a strip-o-gram complete with flying cream pies. Or the stunt they pulled at the 1995 ARIA awards ceremony (the Aussie equivalent of the Grammys), where the band sent Josh Shirley, the 7-year-old son of Frogstomp producer Kevin Shirley,to accept its winner's statuettes.

Sure, it's juvenile. It's also more fun than worrying about record sales marketing plans and impending adulthood. "You always think that if you ver put a record out that it's all fancy hotel rooms and chicks," explains Gillies a few hours before the St. Andrew's show. "And we've seen the other side of it. You gotta do all the shit -- traveling, interviews, stupid photo shoots. All that other stuff is just a big pull." He makes the universal sign for jerking off.

"If I was older, maybe I'd enjoy this a bit more," Joannou says of overnight success. "I'd fell freer, not like people were watching me all the time."

So what do the members of silverchair like about their instant stardom? "The music," says Gillies without a momen't hesitation. "Playing. It's cool, too, because me and Daniel and Chris have been good friends since primary school,when we were 5 and 6." He brushes aside the long, dark brown hair falling over his face and smiles with radiant satisfaction. "It's really cool," he says, "to be able to do this kind of shit with good mates, isn't it?"

To appreciate the speed with which silverchair have risen from practice sessions in the Gillies family garage to Buzz Bin and beyond, dig this: The first big-time rock band that Daniel Johns, Ben Gillies, and Chris Joannou saw live was the popular Aussie group Screaming Jets in the summer of 1994 at the 3,500-seat-capacity Newcastle Workers' Club. The boys were also the opening act.

"It was sold out, and we were pretty nervous," recalls Johns, who was 15 at the time (Gillies and Joannou were 14). "It was just after we got a record contract. We played and then we got to go upstairs in to the VIP area and watch the Jets.

"But it was pretty, weird," he adds with colossal understatement."The Jets sounded so good. We thought we must have sounded like shit."

Even with a hit album and six months of international touring behind them, silverchair criticize themselvers with an intensity that is worse than anything they've received from the rock press. It's partly an Australian trait, a preemptive reaction to what is known there as the "tall poppy syndrome" --- cutting someone down to keep his ego in check. For the band members, it's also a self-awareness thing; they know just how fucking lucky they are.

"There are so many other bands our age that could really kick our ass," says Johns quite earnestly. "But no one really knows about them beacause they're still playing in the garage and can't get gigs. Just like we did."

"In the early days, I'm sure a lot of people used to come and see us just to see how shit we were," chortles Gillies. "And I think some of them still do."