Imagine you've picked the perfect costume for Halloween, spent hours designing it, tested it on your little sister. There has never been a scarier Halloween costume. But then about halfway through your rounds, your mask starts to itch. It's hot. It gets slimy from condensation. The elastic hurts your ears. People can't hear you talk. You can't see through the damned little eyeholes. But you can't take it off and thwart your efforts to be the scariest clown on the block, can you?

Of course not.

Now imagine if every day was Halloween and you might get a sense of what life is like for Slipknot.

Playing a sold-out show at the Shaw Conference Centre tonight, these nine otherwise normal dudes from Des Moines, Iowa, decided early in their career to wear masks and now they're stuck with them. Remember when Kiss took off the makeup? A repulsed public demanded they put it back on. Mudvayne - a Slipknot spinoff - tried to go out with no costumes and were rewarded with no record sales. And so Slipknot remains at the top of the heap of scary heavy metal clown bands and they owe a good deal of their success to their provocative image. No wonder they're so angry.

Percussionist Chris Fehn - a.k.a. "No. 3" in the band's anonymous onstage lineup - admits that not a day goes by that they don't rue the day they donned disguises.

"Yeah, it sucks," he says in a recent phone interview, though he's quick to add that it's also "cool." Performing as monsters - think pinhead meets The Silence of the Lambs - is actually very "liberating," Fehn says. The musicians can do things they might not normally do if they were, well, normal.

"Now it's such a part of us that we kind of forget it's on," he says. "We don't know it any other way."

Comparisons to Marilyn Manson are inevitable. Ironically, however, some of the music of Slipknot is scarier and more violent than anything Manson ever came up with - nine times scarier, even - yet this nonet has never got even a fraction of the flack. Why? Didn't take on the Christians, that's why.

Fehn explains, "We never pitched that whole religious angle. That's not what we're into. We're more into real emotions and the realness of everyday life. We're not a political or religious band. Who knows what all that crap's about anyway? Everything's so crooked now, it's like, whatever. We leave that to other bands. Not that we don't have a personal interest in it, but as far as our music goes, it's not something we play into."

So what does Slipknot play into? The fans ought to know more than anyone. From the venomous rage of their last album, Iowa, Slipknot's latest release, Vol. 3 (The Subliminal Verses), is a stark contrast, at least lyrically.

There's even a gentle acoustic ballad called Circle that seems completely out of character, beauty from the beasts. Fehn describes Iowa as "our Empire Strikes Back record" from the "dark, heavy, hard period," written and recorded in such haste that it all turned into a blur. Slipknot had much more time with Vol. 3, recorded with producer Rick Rubin (Marilyn Manson, Johnny Cash) in a house supposedly haunted by the ghost of Harry Houdini. Mildly supernatural events were experienced - flickering lights, odd sounds and whatnot.

Fehn laughs, "It's just typical Slipknot. We wouldn't do it anywhere else."

Overall, the new material suggests this band isn't just a one-trick nu-metal monster. Fehn says he expects everyone in his band to be playing music well into his 60s.

"This band is timeless," he says, working into a carnival-barker spiel typical of the scary metal band genre. "There are no heroes in the world right now, unless you got to see Metallica or something like that, and I think we fit that role. We're something kids can grab hold of and still enjoy when they're in their 40s. I've liked Metallica since I was 11 years old. Twenty years later, I'm touring with them and I'm still watching every show. I just love it. I think we're that next band."

Even with masks?

"This band is just non-stop. We've got so much talent and so many variables in this band that it could last forever."

Alice Cooper is still going strong, so you never know.

Scary clown bands we have known include:

ALICE COOPER - Godfather of shock rockers. Known for mascara, straitjackets, live snakes, depicting murder on stage, good golfer.

Defining work: Welcome to My Nightmare.

Scary lyric: "She's cool in bed. Well, she oughta be 'cause Ethyl's dead."

GWAR - Alien monsters' stated mission to "destroy humanity." Beheads effigies of annoying pop culture icons on stage, spews various fluids into the crowd at concerts.

Defining work: Pretty much anything.

Scary lyric: "I hate flowers and little birdies. Makes me wanna puke when I see something cuddly like you."

INSANE CLOWN POSSE - Violent clown duo from Detroit rap about torture, rape and murder in painstaking detail. Fans are called "Juggalos."

Defining work: The Great Milenko enjoyed a media boost in 1997 when the album was banned by their own record label, Disney-owned Hollywood Records.

Scary lyric: "Girl, you know I love you, but now you gotta die."

MARILYN MANSON - The new Alice Cooper earned the wrath of the American establishment not so much for being a scary clown - which he was rather good at - but by dissing Christians.

Defining work: Antichrist Superstar.

Scary lyric: "White trash, get down on your knees. Time for cake and sodomy."

KISS - Quartet of rock 'n' roll kubuki clowns offered bored teenagers in the late '70s a blessed alternative to disco. Since broken up, but still a marketing juggernaut.

Defining work: Alive.

Scary lyric: Not really a scary band per se, but the ubiquity of the lyric "I wanna rock 'n' roll all night and party every day" is kind of frightening.

HORRIBLE MENTION: Rob Zombie (horror comic-obsessed singer), the Misfits (venerable horror-punk band), Mudvayne (Slipknot spinoff), Mushroomhead (Slipknot-like band claims to have been playing scary clowns longer than Slipknot), Twizted (Insane Clown Posse spinoff), the Mants (defunct Calgary band that wore giant ant heads).