These ads take 'viral' marketing to a whole new level: To promote the new Steven Soderbergh movie 'Contagion,' a group of microbiologists and immunologists were tapped to create a billboard out of bacteria.

Starting with two poster-sized petri dishes, they treated them with bacteria and fungi and let them grow into the film' logo and title. The result is both creepy and a little gross, a perfect fit for a movie about the spread of a deadly disease.

Check out the making-of video below:

[via Movies.com]