We look at the music career of the former star of ''Welcome to the Dollhouse''

The fifth annual Oyster Bay High School talent show feels as all-American as the U.S. flag at stage left. Inside the colonial-mansion-style auditorium on April 15, teenage girls earnestly croon ”You Must Love Me” and ”Send in the Clowns”; the student jazz-rock ensemble jams on a Dave Matthews Band song. Parents clutch video cameras and munch baked goods. The only thing askew is the last listing in the program: ”Crash Course — Heather Matarazzo, soloist.”

Yes, that Heather Matarazzo — the tortured-geek star of the art-house fave Welcome to the Dollhouse, now an Ivory-complexioned 14-year-old freshman at this public high on New York’s Long Island. Between homework and softball, Matarazzo still pursues acting, recently in the upcoming Keanu Reeves thriller Devil’s Advocate. But tonight, her classmates and family will witness the debut of Heather Matarazzo — rocker.

”Music’s always been a part of me, and I thought, ‘What better way to express myself than tonight,”’ she chirps pre-show. Matarazzo may resemble your typical high schooler, but her musical tastes would terrify Dawn Weiner. She hates the Spice Girls, adores Courtney Love, and just purchased the Lost Highway soundtrack (”I love Trent Reznor”). ”I have no idea in which way it speaks to me,” she says of her grunge inclinations, ”but I know it does.”

The curtain reopens for the show’s finale, and out comes Matarazzo, wearing a non-grunge blue print blouse and cradling her electric guitar. She plays a soft, instrumental rendition of Nirvana’s ”Stay Away,” but only for a minute. The music stops, and Matarazzo brusquely strums the opening chords of ”the best song in the world” — Hole’s ”Violet.” She interjects a few Love-style wails into her wispy singing voice, and students squeal and bop in their seats.

The song ends, but the performance doesn’t. Matarazzo puts down her guitar, grabs another, walks purposefully to the front of the stage and — as parents and teens alike jump up in shock — starts smashing it to bits. An impromptu mosh pit breaks out on stage, and Matarazzo whirls herself around as the song crashes to a halt. Kurt Cobain would have been proud.

Before the show, Matarazzo was asked if she wanted to rock full-time. ”No way,” she said. ”I’m just doing this for fun.” But as soon as she is off stage — and right after she’s puked, out of sheer nervousness — the world’s least expected riot frosh is singing a different tune. ”It was such a great rush,” she swoons. ”It was the best!” The Weinerdog has left the building.