LEWISTON – Even before the first of four thundering metal bands began performing Saturday – including Grammy nominees Killswitch Engage and Lamb of God – the mosh pit formed and the slamming began.

Amid an open circle in the mob, men bashed into each other, bounded away and returned.

“It’s a rush,” said Erich Day, 21, of Bridgton. All the energy of the bands’ predatory rhythms and growling lyrics is released.

But there’s an etiquette in the mosh pit, too.

Though the city-owned Colisee posted guards to watch over the mob and keep the pit civil if not civilized, most members of the pit watch themselves.

“Everybody looks out for each other,” Day said. “There are occasional jerks. But people pick each other up.”

Such displays are routine for the bands that played here Saturday night.

The two headliners were preceded by SoilWork, who were introduced as “Sweden’s own Vikings of mass destruction,” and DevilDriver, whose sound was distinguished by its ability to be even louder than its Scandinavian opener.

“They are why I’m here,” said Travis McCorison, 22. He and a buddy, Thomas Crocker, 22, drove down from Old Town for the show.

Crocker came for “Killswitch Engage,” which originated in Westfield, Mass. McCorison, swilling beer before the show, pulled his shirt off before the band took the stage and yelled to his buddies over the music playing on the loudspeakers.

“It’s all about the energy,” he said.

Not that everyone could control themselves.

Even before DevilDriver took the stage, police had arrested two men for disorderly conduct, Lewiston Police Sgt. David St. Pierre said.

Both men were drunk and stopped before they ever entered the arena.

At least 2,100 tickets were sold in advance of the show, with hundreds more expected to purchase tickets before the final band began to play, said Kellie Morris, spokeswoman for the arena.

The Colisee can seat about 4,500 people for a concert.

Few people were seated as these bands played.

Many stood on the floor, while others stood and bobbed their heads in time with the musicians, bathed in blood-red stage lights.

As they played their last number, SoilWork lead singer Devin Townsend encouraged the bobbing heads: “aye! aye! aye!”

When the performance ended, the arena went silent. Then the loudspeaker kicked in with a recorded tune.

The singer: Tom Jones. The song: “It’s Not Unusual.”