The J-pop band Babymetal might be ready for American mainstream; on Wednesday they appeared on The Late Show, a trio of chipper, hyper-choreographed Japanese girls harmonizing and talk-singing about eating chocolate while their kabukified metal band played their asses off. The guitars shredded, the drums did that blast beat thing, the girls—lead singer Su-metal, backup singers Yuimetal and Moametal—screamed and danced and looked both super-cute and super-serious.

The audience response, as far as I can tell, was happy bafflement, which seems to be the most common reaction to Japan’s more charming exports. Somehow Babymetal’s whole thing works, this cross-pollination of happy-happy J-pop and speed metal, the tension/release of gravel-crunching riffs coupled with chiptune aesthetics and kawaii theatrics and songs about the cruelties of bullying.

It could be that Babymetal is a novelty act, talent notwithstanding; Japan’s appetite for fads is gluttonous and paradoxical. But Su-metal, Yuimetal, and Moametal have been performing together since 2010. Six years is forever in the pop business and every year the band becomes less of a Harajuku-inspired, fan-service corporate creation, and more of a legit metal group, certain of its place within a genre it sort of invented (kawaii metal, melodic J-thrash, call it whatever). They have the iconography (a recent show had Su-metal “crucified” on a massive red cross while the crowd chanted Death! Death! Death!) and the chops. It worked for Slayer, it worked for Iron Maiden, it worked for Motorhead. Why not Babymetal?

The American metal community doesn’t know what to do with them—how do you maintain your metal cred while three girls in GothLoli outfits run around the stage to DragonForce-inspired solos? Here’s what you do: drop the scowl and have fun. So what if Lady Gaga used them for an opening act during her artRave tour? Bet you Five Finger Death Punch would do the same.

Babymetal’s second album Metal Resistance dropped worldwide April 1st (sly timing) and a world tour is underway.