A heavy metal singer met the not-so-jolly version of Santa up in NorCal -- where an insult hurled at the guy's city didn't land so well for him ... although, he did land punches. A deathcore band called Smack'd Up was recently performing up in Sacramento in what appears to be some kind of low-key show in a warehouse ... and not packed at all. Frontman Matt Kupers was on the mic and apparently got frustrated with the energy in the room. He stops his gig to chastise the crowd, saying he thought he was in Sac Town and that the audience would bring it. He hurls some expletives and essentially jabs at the residents. Welp, some dude out in the crowd -- who was dressed as Kris Kringle -- didn't like what he was hearing, and he rushed Kupers onstage ... hopping up and starting to whoop on him. The fight only lasts seconds, but it ended with Kupers falling over and landing on his ass. No word on whether this escalated into anything further -- legally speaking -- but on its face, it looks like they just left it there in the streets. The lesson ... Sacto throws down, baby!
