Yes, on tuesday, June 13, 1978, voodoo rockabilly avatars The Cramps (in their greatest line-up, Lux Interior and Poison Ivy backed by Nick Knox and Byron Gregory) rolled into the recreation room of California’s Napa State Mental Hospital, to play for the residents. Don’t ask how this was ever allowed. Just give thanks someone had a camera.

Captured in black and white on rudimentary home video equipment, the 20 minutes of footage here?for 25 years a bootleg (un)holy grail?ranks alongside music’s most sacred artifacts, up there with Johnny Cash’s prison shows, James Brown’s Apollo stands, Dylan’s electric storms of ’66.

“Somebody told me you people are crazy,” says Lux, setting the tone while “The Way I Walk” fires up. “But I’m not sure about that.” As assembled patients, stirred by the sound, begin to shimmy, invade the stage, steal the mic, scream their souls out and try to escape, you might wonder how politically correct this is. But notice how the band treat this audience: exactly the same way they treat every other audience. The wildest night. The band may have sounded (fractionally) better on occasion, but they’ve never been so completely… cramped. The very stuff, people, of legend.