On the first day of the Bamboozle, the nine-stage rock festival spread across an East Rutherford, New Jersey parking lot, only one group of unlikely special guest superstars could outshine much-adored headliners Fall Out Boy. Still riding a two-year wave of rediscovery, arena-rock diehards Journey appeared as the secret performers for a four-song set. Or “Journey” as it turned out — the group appears to have been a stellar Long Island cover band called Evolution. Blasting out “Separate Ways,” “Faithfully,” “Any Way You Want It” and the still totally unkillable “Don’t Stop Believing,” Evolution — who many in the crowd, including this reporter, mistook for the real deal — cued a wildly mixed audience reaction, some fans literally shrieking or running towards the stage, others angrily storming away en masse. But even with a few freaked audience members gone, a triumphant “Believing” got a louder, more powerful sing-along than anything else the entire day.

Fall Out Boy kept the energy high with a set heavy on hits, strobe lights and Andy Hurley, one of the most animated drummers around. For a show heavy with costume changes and videos, the band was clearly trying to keep things loose and casual. Cassadee Pope from Hey Monday helped sing the chorus to “Sugar We’re Goin Down” and bassist Pete Wentz shared a lengthy motivational speech apparently fueled by having watched Marley And Me. The band did their cover of Michael Jackson’s “Beat It” and ultimate party anthem “Hey Ya” by OutKast, the latter so seemingly spur-of-the-moment that the band stumbled over the bridge. When Wentz introduced it with, “I feel like everybody wants to dance right now,” that could have been any part of a pepped-up day where just watching bands could feel like overstimulation.

The rest of the day had a high-energy carnival atmosphere, from the ferris wheel to the bumper cars to (not kidding here) monkeys riding dogs. People came dressed as luchadores or Teletubbies. Since this is a Wonka-sponsored event, everyone was wired on a seemingly endless supply of free Kazoozles, Nerds and Tinglers. Accordingly, all the bands seemed to want to out-spazz each other: from electro-dorks LMFAO leaping all over the place and begging to see breasts, to GWAR giddily decapitating their version of Obama and coating the audience with a triumphant arc of stage blood.

Kid Cudi tried to rock the Kazoozle Stage in a stylish leather jacket, hoodie and sunglasses combo, but the 68-degree heat and energetic crowd made sure they were all off by set’s end. Although hit single “Day ‘N’ Nite” brought out the most camera phones and cheers, the audiences went wildest for high-BPM mixtape tracks like “Cudi Spazzin’ ” and “I Poke Her Face.” Afterwards, rising MC Asher Roth hopped around like a pogo stick, demanding the audience bounce and jump along at every opportunity. Without a full mastery of between-song banter, the rapper occasionally goofed around on stage in his mellow style, and his fun was infectious. Asher and his three-man crew even did a little synchronized goofball dance to Soul For Real’s bubblegum R&B classic “Candy Rain.”

In the same vein, Gabe Saporta of Cobra Starship included some choreographed between-song silliness in his own set with one of the dudes from Sing It Loud. Cobra Starships’ M.O. was perfectly clear: “We like to shake our ass, but at the same time, we like to fuck shit up.” And the neon-clad band tore through their set with tossed mic stands and funky numbers like “Kiss My Sass.” Even ’90s alt-rock mainstays Third Eye Blind got into the dancey act, peppering their set with chants like “To the left y’all, to the right y’all.” Set to release their first album in six years, 3EB got a warm welcome and one of the most vocal crowds of the day. The band treated the audience with some newer tracks that had a Fall Out Boy vibe, as well as an extended version of their rock-radio classic “Jumper” — complete with cowbell-and-agogo-heavy drum solo. Big hit “Semi-Charmed Life” was the natural closer, with a little bit of Nelly’s “Ride Wit Me” thrown in for kicks.

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• Fall Out Boy’s Video Tour Diary
• Asher Roth’s Nonstop Party