BERKELEY — There’s a variety of ways to spend a milestone birthday. You can take a trip, for example, or get together with long-time friends. To ring in his 60th, vocalist Maynard James Keenan did both. He got his bands A Perfect Circle and Puscifer, as well as legendary Bay Area band Primus, to go on tour together. Dubbed Sessanta, Italian for “60,” the trio arrived at the Greek Theatre Sunday for a unique performance.

Rather than the usual format of bands playing one at a time, this show was a living organism with mini-sets and collaboration, allowing band members to join other bands’ sets. This format flowed with almost no down time. That equated to about 30 songs over three hours for the sold-out gig.

“I smell marijuana; let’s see how stoned you really are,” Keenan announced early on, looking for a response.“You are very stoned.”

There was no filming allowed at the show up to the finale jam that brought all the musicians on stage together. The rules were introduced by a video of Keenan acting as an old-timey broadcaster introducing Spam, and adding that anyone caught filming would be thrown into the grinder that becomes the meat-like product. Once he was on stage he said it again to drill down the message.

“We want you with us; we’re gonna stay connected through the entire birthday party,” Keenan said. “Then your neighbor doesn’t have to watch the show through the screen of your phone. If you can’t do that for three hours, there’s probably something wrong with you.”

A Perfect Circle, the first band of the evening, is on tour for the first time since 2018. The band recorded a new track, “Kindred,” to mark the occasion. The band brings a darker melodic right-brain energy compared to Tool’s left-brain power and intensity. It was  unusual at first to have the man of the hour hit the stage right away without an opener, but the crowd was enthused to see him so early.

Keenan stepped to the top of the riser as guitarists Billy Howerdell and James Iha and bassist Matt McJunkins walked to the front of the stage for the warlike and slow-burning “The Package.”

After Puscifer co-vocalist Carina Round rolled out a cart with party hats and other birthday trinkets to the stage, the band moved into a pair of ethereal and atmospheric tracks from A Perfect Circle’s most recent album, 2018’s Eat the Elephant: “Disillusioned” and “The Contrarian.” Round joined in on the singing.

Often shrouded in the darkness next to the drum riser during a Tool concert, Keenan, wearing a suit, spent plenty of time at front of the stage. Despite entering his sixth decade, Keenan’s voice was powerful.

Bars of vertical lights with columns of circular spotlights shot back out at the crowd and cascade over the stage. There were two large ramps at the sides of the stage, while the three drum kits of each band sat next to each other atop the riser. This setup left no need for set changes between bands. The top corners of the stage actually had couches and chairs for the non-performing musicians to lounge in or come and go. It felt like a living room with about 8,000 house guests.

“I love this place; this is one of the most amazing venues on the entire planet,” Primus bassist and vocalist Les Claypool said as his band took the stage.

The evening also offered a debut of a newly renovated Greek, with the general admission and lawn area getting a facelift. The lawn is now tiered with new flat layers of grass added for seating. To each side of the lawn is a pair of additional seating areas, one with rows of chairs and the other with benches and standing tables. The changes did not go unnoticed by Claypool, who said he spent a portion of the day before the show exploring the new digs, giving it a positive review.

“I remember seeing shows up there on cheapskate hill, but that’s no more,” Claypool said.

Primus started with a four-song set of “Those Damned Blue-Collar Tweekers,” “Too Many Puppies,” “Sgt. Baker” and “Follow the Fool.” Claypool acted like the emcee of the party, keeping the energy moving, his frenetic bass lines providing the pulse of the music.

Puscifer was next in this round robin, the band veering into experimental and alternative territory. Keenan shared vocal duties with Round, adding an extra layer of depth and texture to the sound. The two played off each other magnificently, sending energy back and forth, writhing and stomping on the ground with the flow of the music. The band played “Galileo,” “Tiny Monsters” and “Indigo Children.”

Throughout the night, videos of an aging Keenan were mixed in; in one, the singer was shown telling some purposely eye-roll-inducing grandad jokes that made for a funny interlude to introduce Act II.

“What are bears without ears?” he asked. “…Buh…” There was a purposeful long pause of dead silence.

Primus returned for a trio of rousing tracks that got some of the biggest responses of the night, including “Jerry Was a Race Car Driver” and “My Name is Mud.” On the latter, Claypool briefly paused to announce a mid-song epiphany:

“I wrote that bass riff right here in the dressing room,” he said. “Let’s write another one here.”

Keenan then joined Primus to deliver the wordy, light-speed vocals on “Tommy the Cat.”

As the show went on, the stage revealed a few extra quirks, such as the tiny platforms the band members sat on could move up or down the stairs like a lift. Claypool rode a seat up, playing increasingly higher notes.

“You know what I realized, Maynard?” Claypool asked before the song. “You’re now an OG—original gummer.”

Puscifer performed a stunning series of songs, including “Flippant,” “Momma Sed” and “The Underwhelming.” As the sun began to set, the lights and staging really began to stand out. A perfect Circle stormed back with a set including “The Hollow,” “So Long, and Thanks for All the Fish” and “Weak and Powerless.”

After a brief intermission, the third act brought had the bands performing even closer together. The musicians played their individual songs from the recently released Sessanta EP in quick succession before everyone joined forces with a performance of “Grand Canyon,” a Puscifer song.

Follow writer Mike DeWald at Twitter.com/mike_dewald. Follow Derek Tobias at Instagram.com/shadowsandstrobes.