Trends that make otherwise average people wear clothes backwards, say, or pierce unusual outcroppings of flesh, often, of course, become cringe-worthy years later. Perhaps it was coming to terms with the embrace of pastel colors and technologically advanced hairspray; maybe it was the accretion of weird chemicals in the water supply, but in the ’80s, part of the metal scene went haywire. Somehow wrestling shoes and neon paint splatters made sense in the pop or New Wave scenes, but the “hair metal” bands of the ’80s looked all wrong when they juxtaposed music tailor-made for pissed-off boys with painted faces that would make Barbie look butch.

Many were the diehard metal fans who would sooner listen to Cyndi Lauper than Poison or Cinderella, but L.A. was nonetheless the center of an ’80s metal scene with a whole new look. In 1988, Penelope Spheeris released the second in her Decline of Western Civilization documentaries, and in this one (dubbed The Metal Years) she ventured into the frizzy heart of that metal scene.

Though plenty of rockers hailing from an earlier, less goofy rock era show up, from Aerosmith’s Steven Tyler to Ozzy Osbourne and Motorhead’s Lemmy, most of Spheeris’ subjects are hair metal devotees and performers. Most sport fern-like dos, made-up faces, and songs that make Spinal Tap look Nobel-worthy. Things reach their silly peak when the band London breaks out a Soviet flag to burn, following that with the nearly meaningless “Russian Winter”: “Snowbound, just like a Russian winter, yeah/ hellbound, just like a Russian winter in the U.S.A.” London also shows off its home digs—the band is filmed hanging out of a speeding old truck with a camper on the back.

The movie is full of such face-palm moments, from dimwitted performers bragging about penis size to a wonderful sequence in which Ozzy discusses his life in Black Sabbath while cooking eggs and bacon for breakfast. (He also famously misses his glass when he tries to fill it with juice, a moment that may or may not have been staged.)

All the same, the film gets into serious territory. Chris Holmes of W.A.S.P. gets blind drunk and self-abusive in his swimming pool with his mother watching, and two musicians show up to be stout antidotes to all the insanity. The down-to-earth Lemmy merely stands on a hillside smoking, offering common-sense views of his profession. Dave Mustaine of Megadeth proves his bona fides as an earnest spokesman for his music, almost singlehandedly transcending all the hairspray.

The must-see film for music fans who survived the ’80s or who don’t know how bad things really were opens this Wednesday at Pleasant Street Theater in Northampton.

*

In other news, the UMass Doo Wop Shop, which boasts the descriptor “UMass’ only all-male a cappella group,” hits the stage at Smith’s John M. Greene Hall to raise money for the American Cancer Society. That event was largely organized by Heather Craig because, she explains, of her appreciation for the group’s role in relieving stress during her husband’s illness. The Doo Wop Shop was founded by students in 1993, and, though the roster has changed over the years, the group continues to sing a huge number of shows for charitable causes.

April 28, 2 p.m., $15, John M. Greene Hall, Smith College, Route 9, Northampton, (413) 586-8686 or www.nbotickets.com.