100 gecs’ funhouse-mirror pop dazzles at the Royale

100 gecs played to a sold-out crowd at the Royale.Nathan Klima for The Boston Globe

Guilty pleasures be damned: Experimental pop duo 100 gecs makes genre-mashing bangers that reject all notions of musical snobbery in favor of the good time that lies beyond, and they’ve become unlikely tastemakers in the process. At the hands of songwriter-producers Laura Les and Dylan Brady, decades’ worth of critically derided sounds — Auto-Tuned bubblegum pop, crunkcore, screamo, dubstep, and plenty more — melt into mischievous, often earnest tunes that revel in maximalism for the dazzling hell of it. The effect is only sweetened by the fact that their 2019 debut album, “1000 gecs,” catapulted them to the top spot of both the New York Times’ and VICE’s best-of-the-year lists.

Naturally, anticipation was high for Monday night’s sold-out performance at the Royale, which marked the band’s first headlining show in Boston after the pandemic scrapped their 2020 world tour plans. Their previous Boston outing, an opening slot on Brockhampton’s 2019 arena tour, showed them working out the kinks of a relatively untested live performance, but Monday night demonstrated that they’ve found their footing since then. Following an enthusiastically received opening set from hyperpop up-and-comer Alice Gas, Brady and Les bounced onstage donning yellow and purple wizard robes, in front of an LED backdrop modeled after the Windows 95 “3-D maze” screensaver. Head-banging and flailing between a massive set of prop speakers, they drew heavily from “1000 gecs,” with fan favorites such as the trash-talking “Money Machine” and electroska “Stupid Horse” sending the crowd into a frenzy somewhere between a hard-core show and a rave, breaking from the bangers only for an impish xylophone duet and an acoustic (yet still heavily Auto-Tuned) rendition of “gecgecgec.”

Laura Les of 100 gecs at the Royale, the duo's first headlining show in Boston. Nathan Klima for The Boston Globe

For all their eccentricities, 100 gecs have figured out what it takes to deliver a strange show and sound that actually connects. Les and Brady are self-professed scholars of the Billboard Hot 100, and while they might occasionally end a hard-core breakdown with an abrupt slide whistle or sound like a Casio keyboard losing a barfight, it’s a deep affection for pop music that makes their songs stick. Even the unnamed new tracks sprinkled throughout their set suggested a certain trend-savviness, evidenced by lashings of industrial emo-rap and their own spin on riff-heavy, Machine Gun Kelly-ish pop-punk. The spectacle of it all might be the initial draw, but infectious, holler-along hooks invite audiences to join in the fun.

And join in they did. A hard-dancing, crowd broke into a spontaneous “GECS! GECS! GECS!” chant throughout the set, eventually summoning said gecs back to the stage to encore with weed ode “800 dB cloud” and another unreleased track revolving around the chorus “damn, what’s that smell?” As a giddy crowd poured out of the building and into Tremont Street after the show, it became clear: “that smell” — a pungent medley of vape smoke, Gen Z mosh-sweat, and hundreds of spilled drinks — was the lingering effect of gecs.

100 GECS

With Alice Gas. At Royale, Oct. 25.