Before a single musician could take the stage, the surprises were already beginning. After performing an unannounced set together in the Comedy Tent earlier in the day, Zach Galifianakis and Jon Hamm teamed up once again to start off the late night party with a duet of "We Are the World."
From then on the announced and unannounced guests popped in for a song or two (or four), promptly caused the crowd to lose its collective mind, and then slipped away back behind the stage. Jurassic 5's Chali 2na held down MC duties as the artists reveled in inciting the audience into a nonstop dance party.
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Chance the Rapper -- no stranger at all to guest appearances at this 'Roo -- summoned the spirit of Christopher Wallace for a rendition of "Juicy," while Bleachers frontman Jack Antonoff seemed to more closely mirror The Boss. With a confident smile and a repertoire of stage gestures to direct the crowd, Antonoff blasted through Bruce Springsteen's "Dancing in the Dark" and Talking Heads' "Psycho Killer" as the sole lead vocalist.
Later, electronic-soul singer SZA popped in for Michael Jackson's "The Way You Make Me Feel" and then a duet with Antonoff, "Under Pressure," a star-studded collab effort in its own right with throwback heroes Queen and David Bowie.
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"Are you ready to take a trip down memory lane?" asked Darryl "D.M.C." McDaniels when he appeared onstage about two hours after the start of the show. He and Chali 2na performed a double block off Run-D.M.C.'s classic Raising Hell: "Peter Piper" and "It's Tricky." With Chali 2na to the sidelines, Cherub's Jordan Kelley tagged in for Aerosmith's "Walk This Way" and even pulled off a passable Steven Tyler impression. Kelley added a few colorful scarves to his mic stand -- a la Tyler -- and made (what sounded like) sandpaper tearing in his throat during his screechy rendition of the chorus.
Undoubtedly the weirdest moment of the Superjam! also happened to involve Kelley. As the indie-electronic artist sang the incredibly goofy Rocky III song, "Eye of the Tiger," Corey Feldman suddenly appeared onstage in a glitter-adorned jacket and with his eyes glued to the screen of his smartphone.
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By 3:30 a.m., the event's scheduled end-time had come and gone and no one was in any mood to step back into the present. "Well, my friends. The time has come," offered Jamie Lidell as he launched into the first encore, a more than eight-minute version of Lionel Richie's "All Night Long." Chance returned to the stage to finish the night, running through Bell Biv DeVoe's "Poison" and then perhaps the quintessential throwback party song, Montell Jordan's "This Is How We Do It." As the house music came up and the chants of "One more song" faded into the night, the weary 'Rooers who witnessed the entire two and a half hour hour experience knew they had witnessed something special.