LAST YEAR IT WAS AN ESTHETIC invasion of teetering metal cubicles on MacArthur Boulevard. The year before, a Used Wars Lot suddenly materialized at 12th and U NW, displacing the drug dealers. In '85, cardboard figures in Goodwill clothes mysteriously appeared scaling the Lansburgh Building.

Call it junk, call it art. Art Attack doesn't care as long as you call it something. The artists collective that has been shocking Washington since 1978 is about to open a new show this week at the left-of-center Olshonsky gallery.

Moving indoors is something of a departure for Art Attack, whose usual mission, as the artists see it, is to transplant art from exclusive galleries to where more people can see it and react to it -- in abandoned buildings, the streets, wherever.

"People are intimidated by galleries," says Lynn McCary, an arts administrator by day, Art Attacker by moonlight. "They feel

like they shouldn't be there or that they should buy something or compliment the work." She promises that the art in this gallery show will be different. "You can touch it, hit it, change it, yell at it. There are no restrictions."

Unrestricted might be the best way to describe the group's membership, too. Its often changing ranks have included such locally established painters as William Dunlap, Mark Clark and Kevin MacDonald. Art Attack is currently composed of McCary, Jared Hendrickson, Evan Hughes and Alberto Gaitan.

Hendrickson is a performance artist/poet/musician/filmmaker/writer. As he talks about Art Attack's mission, his body contorts in spasms of energy. "I'm not out there to please people or satisfy people," he says, "nor am I out there to frighten them or disturb them. I have to do this for myself or I'll go to the grave a wretched creature." When he's not assaulting the senses of Washington residents, he spends his spare time writing a novel about the "ultimate relationship," a love so passionate it brings about the apocalypse. ("I'm a hopeless romantic," he confesses.)

You'd never believe Hendrickson works with Hughes. This co-conspirator is a solemn presence with thin face and deadpan delivery. He makes exquisite furniture by day but, for Art Attack, he builds such offbeat pieces as the "Wheel of Misfortune," a game-show parody.

Rounding out -- or perhaps squaring off -- the group is Gaitan, who says he handles Art Attack's "aural component." In other words, he does the music. He speaks the language of someone who day-gigs as a computer organizer for a group of surgeons. His conversation is sprinkled with high-tech buzz phrases: "interactive elements" and "purely abstract space" and such. All in the service of "demystifying art."

So, rest assured, while Art Attack may be moving into the gallery scene, it's not going middle of the road. "If we ever become conventional," says a horrified Hendrickson, "we might as well become businessmen or accountants."