Gaunt men with peeling faces and stony-eyed women dripping blood from their mouths leer around corners and loom from behind wrecked equipment, impervious to the bullets from a gun wielded by one of their would-be victims.
And it is all happening right at the heart of the multi-billion dollar complex where, last July, physicists announced the discovery of what they think is the particle -- the Higgs boson -- which made life and the universe possible.
Well, happening at least on the Internet (http://www.decayfilm.com/). Scientists at the centre on Wednesday said they were pursuing their efforts to reveal the great mysteries of the cosmos and had not noticed anything unusual.
"But that does explain why my neighbour shouted: 'Watch for the Zombies,' when I left for work this morning," said one puzzled physicist who is part of one of the two large teams which jointly tracked down the Higgs.
The gory action comes in an 80-minute horror film, "Decay", shot in 2010 around open areas of the sprawling CERN complex at weekends by budding young scientists from Britain and the United States, without formal management approval.
"They asked for CERN's endorsement once the whole thing was in the can," said spokesman James Gillies. "Clearly we can't endorse such a thing, but nor were we going to stop it. After all, it's just students doing the kind of thing students do."
The movie burst onto the World Wide Web, itself invented at CERN 20 years ago. A notice on its site and a press release from the makers, H2ZZ Productions, declares: "This film has not been authorised or endorsed by CERN."
FLESH-EATERS
The cinematic mayhem follows a disaster in the Large Hadron Collider (LHC), releasing the Higgs and its associated particle field which turn dozens of the technicians working around the subterranean complex into "living dead" flesh-eaters.
A group of scientists is isolated in the control room -- which the filmmakers move underground from its actual location on the surface -- and as they try to break out to safety they are picked off one by one by their zombie colleagues.
"It's a bit of fun in the best tradition of B-series Zombie movies," said a CERN researcher who followed the project. "It's well done, but I can't say the acting is Oscar quality."
"They wanted to make the film as unbelievable as possible, and the scientific 'facts' cited in it are laughable, so no-one could take it seriously."
The producers are at pains to underline that in making their technicolour epic they had no access to the actual 27-km (17-mile) circular tunnel where the LHC and the giant particle detectors and magnets are housed.
The writer and director of the film was Luke Thompson, who apart from his studies at CERN is a physicist and doctoral student at Britain's Manchester University, where the film had an early showing at the end of last month.
Co-producer and director of photography was Burton de Wilde, who holds a physics doctorate from Stony Brook University in the United States. The actors came from among CERN's several hundred doctoral or summer students.
The company set up to market the film says it has showings scheduled for several places in Britain, the United States and Europe.
"It might just turn out to be one of those off-the-wall successes," the CERN researcher said.
(Reported by Robert Evans, editing by Paul Casciato)