SAN FRANCISCO - If Tool's riveting performance here Monday night is anything to go by, Canadian fans should brace themselves when the band swings down into Vancouver, Toronto, and likely Montreal this month and next.

Tool hit the stage at the historic Warfield Theater Monday night for the fourth date of their North American jaunt and easily proved they can still stir up their special brand of open nerve endings being brushed by steel wool.

The show started at a frenzied pace as the band barrelled through songs from their new album, "Aenima," rarely stopping for audience chit-chat or grand posturing. Drummer Danny Carey and new bassist Justin Chancellor built heavy and tension-filled grooves, which guitarist Adam Jones spiked with shrieks of feedback. The band created a mood that was both electric and dangerous.

When vocalist Maynard Keenan entered, he began to writhe under the bright lights like a sweaty albino python. His shaved head glowed and reflected light as he danced to the tribal rhythms of his band. The drums were what you would expect to hear on the river banks of Joseph Conrad's imagination, and the sound of the guitar/bass onslaught was enough to shove you back into your seat.

But the power wasn't just in the music.

When Keenan sang, it was as though he was spitting venom at everything he hates in this world. Religion, conformity, pressure and politics were denounced as viciously as Tool's ex-bassist, Paul D'Amour, whom Keenan blamed for the three-year wait for a follow-up to their platinum-selling Undertow.

"If Paul was here, we wouldn't even have a new album," he said before launching into a fearsome version of "Jimmy."

The performance was solid and the stage show was almost frightening, with beautiful and disturbing images projected onto two screens at the back of the stage, images of naked men dancing and the laughing faces of people gone insane.

It was as though that was how the band wanted its audience to see them. When the first chords of "Sober" rang out, a mass of sweating, half-naked men (and a few brave women) ran to the mosh pit and started shoving each other mercilessly, all the while singing along, knowing every tiny nuance of this brilliant song.

To make matters more surreal, the scene in the crowd mirrored the psychedelic, filtered image being projected onto the screen.

No wonder Keenan was laughing as he left the stage.