Zombie Butt Touch … What?

Zombies are known for flesh-ripping, brain-eating and staggering around like frat boys on 2nd and Market at 2:30 a.m.

They’re not known, at least at this point, for butt-touching. That may change. The Zombie Butt Touch 4 is set for April 27 at Underground Arts. It’s a zombifed multi-media extravaganza of music, makeup and a little happy mayhem.

But, er, where did the butt-touching come in?

“We used to have butt touch parties when I was an actor at [Eastern State Penitentiary’s] Terror Behind the Walls,” says head zombie Keith Tritton. “All the actors would dress as zombies and we’d start drinking, get drunk and slap each other’s asses.”

From small things, big things one day come. The first Zombie Butt Touch took place at a private residence in 2007, well before “The Walking Dead” and other zombie-centric obsessions. It grew to the 941 Theater in 2009 where more than 300 attended, but it’s been dormant since.

Zombie viruses are like that.

“We took a break,” Tritton says. “The third one was so successful that we didn’t know how to go about it after that. We always had ideas in our heads about making the next one bigger but it took time to figure out how to do that. We’re really inspired by the venue, the Underground Arts. It’s a cool space and perfect for a zombie party.”

Butt Touch 4 features professional zombie makeup artists, offering their services for free with admission, three rooms of music, immersive blacklight installations, video-mapping projections, interactive theatrical performances, and comely blood fairies.

“The blood fairies roam around the party armed with squeeze bottles of blood,” Tritton says.

Actually, Butt Touch 4 has some heavyweight DJs on the decks. Kindzadza is coming over from Russia and Coral is flying in from Seattle.

“Out headliner is Kindzadza,” Tritton says. “He’s a pioneer in the psy-trance sound and he’s finally coming to the U.S. for a tour.”

He’d better be ready for a butt touch.

“It’s fairly likely you’ll get your ass slapped at some point,” Tritton said. “But it’s not like a free for all, it’s one subtle element.”