If you tuned in to watch “The Walking Dead” midseason finale, there’s a good chance you saw a rather creepy trailer during the airing. In the brief TV spot, a young couple on a date spots a mass of rats on the restaurant patio, and a pair of videographers follow the trail of rats inside a building.

The mysterious teaser’s origins have been revealed: it’s to promote FX’s new thriller series, “The Strain.” The show is due to premiere in July 2014, and it looks the viral promotion for the project is starting early.

“The Strain” comes from Guillermo del Toro, Carlton Cuse and Chuck Hogan and is based on a trilogy of novel written by del Toro and Hogan. The series follows Dr. Ephraim Goodweather as the head of the Center for Disease Control Canary Team in New York City. His team is tasked with investigating a viral outbreak that has a link to an ancient strain of vampirism. 

The strain spreads, leaving the Doctor, his team and a collection of New Yorkers to fight it for the good of mankind. Since rats are known to spread disease, that could be the connection between this subtle trailer and the actual TV show.

The cast thus far includes Corey Stoll, Mia Maestro, Sean Astin, Kevin Durand, Natalie Brown, Jonathan Hyde, Richard Sammel, Robert Maillet, Jack Kesy, Ben Hyland and Miguel Gomez. What did you think of the new teaser?

Posted by:Terri Schwartz