One day Green Day was a fiery little trio from Berkeley with the percussive rumble of the Who, the perfect pop instincts of the Brill Building, and a small but hardcore following on the California skateboard circuit. A millisecond later, frontman Billie Joe, drummer Tré Cool, and bassist Mike Dirnt, all 22, woke up in the heart of the MTV maelstrom. They blanketed the Buzz Bin with ”Longview” and ”Basket Case.” They sold bushels of Dookie, an album whose cover showed their hometown being carpet-bombed with doggie doo. They got banned in Boston when a gig became a riot. ”It was almost artificially fast,” Dirnt says. ”There was no real touching-of-ground, except for touching all of the ground in the United States.” Literally: When Green Day touched down at Woodstock II, fans pasted the band with foul patches of sod. A fracas ensued; Dirnt cracked three teeth. ”No big deal,” he laughs. It doesn’t hurt when it happens so fast.