As Halloween draws near, members of the undead are planning to crawl into downtown Langley as part of an annual flash mob.

At 4 p.m. on Friday, zombie dancers will congregate in front of Callahan’s Firehouse on Second Street and move to the beat of Michael Jackson’s “Thriller.” Young trick-or-treaters may be caught unaware by the eerie spectacle, which has coincided with Spooktacular Langley for the past few years.

Perhaps because it’s the unlucky 13th year for the event, organizers Daunne Zinger and Sue Jobst have had some difficulty finding dancers.

“If anyone is dying to participate, we have one more rehearsal before our flash mob,” Zinger said.

She advises people to email her at zingerd@whidbey.com for a rehearsal schedule and performance details. Dancers follow the same choreography in the famous “Thriller” music video, and step-by-step instructions can also be found at thrilltheworld.com, an organization dedicated to the worldwide simultaneous dance movement.

On Whidbey, dancers have been meeting twice a week to rehearse since the beginning of October.

“The thrill of seeing all the kids thoroughly enjoying us doing a flash mob is pretty inspiring to us,” Zinger said. “All of us that do it are lovers of performing. So any excuse to get out in front of people and dance, we’re certainly not going to turn that down.”

Zinger is a teacher at Island Dance, and Jobst, her fellow flash mob co-organizer, is the dance captain for her Luigi Jazz dance class. A core group of dancers join the zombie flash mob every year, but newcomers are always welcome.

Apart from wild moves, the flash mob is notable for its gruesome makeup and costumes. Pale faces, tattered clothes and blood feature heavily. Zinger explained that the premise is that the costumes reflect what the wearers were doing either professionally or at the time of their death.

“For those of us who like Halloween, it makes perfect sense,” Zinger said.