A little over five years ago, Les Claypool was howling into a microphone to a sweaty, absolutely bewildered crowd at Bonnaroo. Needless to say, he’s made quite a splash on the scene since then, and probably owns the unofficial record for most fans won over to an unlikely genre. Now that Tool has tapped into the Bonnaroo generation, one might expect to see a Claypool-like assimilation of their music and live show into the iPods and summer plans of open-minded music lovers.

Tool may not have the extended song repertoire that many touring bands have, nor do their setlists change much from night to night. However, as their recent 4th of July Summerfest performance showed, a Tool concert is quite the thing to behold, and whether the harder edge suits you or not, most can’t help but come away impressed by their magnitude and smart ferocity.

“Let’s begin, shall we?” said frontman Maynard James Keenan as the band launched into the pounding opener “Jambi,” the first of several songs from their 2006 release 10,000 Days. As simple as his opening statement was, it probably could not sum up any better the whole ideal of live Tool. The show begins, almost like some complex math equation, and requires each fan to follow along to the precisely scripted music, cutting green lasers, and dark, abstract videos.

Tool’s music comes at you hard, in many directions, and without a stop. Prog-metal classics like “Stinkfist,” “Schism,” and “The Pot” erupted the crowd early in the set, while a long, drawn out instrumental that pulsed and swelled zoned out the entire amphitheater with dizzying visual effects. Some may have called this a “jam,” but each chord and reverberation was entirely planned with a purpose in mind. What that purpose means is entirely up to the individual, but it was very clear that there was something to be understood in the exactly two-hour set. Tool even prefers to skip the encore. Perhaps they feel that such a break in the action would dilute the meaning of the two hours they spent crafting.

After ending the show with the hard-hitting “Vicarious,” the four members of the group gathered mid-stage and had a group embrace (a sort of strange sight after seeing them thrash the shit out of things for two hours). Performing means a great deal to them, and after throwing a few token water bottles into the masses, it was obvious they were glad the crowd was a part of the experience. Sometimes a simple connection like that is all it takes to lock a new legion of fans into one of rock’s most progressive and exciting acts.