The way you sell movie tickets to something like Contagion, Steven Soderbergh’s disturbing new thriller about a global pandemic, is, of course, to scare the bejesus out of people. The trailer with Gwyneth Paltrow’s eyes rolling around in her head does a pretty good job of it. But apparently, that wasn’t enough, at least not by the lights of Warner Bros. Pictures Canada. They decided to spread the fear by visualizing the spread of the virus itself.

Late last month, the studio tapped a team of microbiologists and immunologists to grow a pair of “bacteria message boards.” The scientists injected two giant Petri dishes with a concoction of live bacteria, including penicillin, mold, and pigmented bacteria, then placed the dishes upright in an abandoned storefront in Toronto. Over night, the bacteria sprouted the word “Contagion,” in all its splotchy, fuzzy-blue glory. You can watch it grow, too, (lucky you!) in the timelapse video above.

No idea if Warner Bros.’s little exercise in guerrilla marketing convinced anyone to head to theaters, seeing as how the billboards weren’t scary as much as they were just plain gross. We, however, would’ve payed good money to watch people pass by them all day. Their expressions–redolent of someone taking a big whiff of sour milk–were cinematic enough.