They call it the bends, and in scuba diving it can kill you.
Either that, or the too-fast surfacing from the ocean deep can cause delirium and hallucinations.
It was a little bit of both depth charges that sounded last night, as Britain's Radiohead brought its intensely beautiful noise to a sold-out RPM club.
The new album is called The Bends, and in the sweaty confines of RPM the music from it seemed to travel through droplets of water, to be absorbed by both the ear and the body.
Radiohead boasts a first-class singer in the carrot-topped Thom Yorke, who can reach the high tenor range of such fellow sonic craftsmen as Jeff Buckley and Grant Lee Phillips. He's also no small talent on guitar, both electric and acoustic, and flanked by lead guitarist Jon Greenwood and rhythm guitarist Ed O'Brien, this was a band capable of great power, as they demonstrated in songs like "Just" and "Anyone Can Play Guitar."
The latter tune was preceded with a small personal note by Yorke, about the killer headache he was experiencing. "I'll dedicate this song to my migraine, which I've got at this moment, and I've got to kill somehow," he said.
Most migraine sufferers try to reduce noise, vibration and light. Yorke went the opposite way, pogoing about the stage with high energy, as if he was trying to knock the beast out of his head.
Either that, or he was willing to let Colin Greenwood's pulsing bass lines eradicate the pain, a tactic that might have worked on the alternately soft and heavy "Planet Telex."
Other times, Yorke was the picture of serenity, strumming on acoustic guitar as he sang the delicate "High & Dry" and the U2-sounding "Fake Plastic."
The show kept building toward the inevitable playing of "Creep," the hit single that had the band unjustly lumped in with too many one-song poseur acts from Britain.
"We've got other songs," Yorke said, almost apologetically. "This is one of our songs. We still like this song, and we don't care that it's been played to death."
Maybe it has been, on radio at least, but no apologies were needed.
Yorke and Radiohead brought more than just one fine song to RPM last night, more even than a few fine songs.
They also brought a feeling that they really are in it for the music, not the music magazine covers, and for the listener, that can cause the most beautiful hallucinations of all.