AMC lets The Walking Dead loose

While the heart of AMC's The Walking Dead series is the relationships between characters, it's the scenes with zombies that typically drive social media chatter. So for the show's season three return earlier this year, Leo Burnett engineered a buzz-worthy zombie idea to help augment awareness and excitement for the show 10 days before its return.

The agency created eight-feet-tall rotting zombie hands and placed them in the middle of Toronto's Union Station. A finger from the installation was cut off each day, "counting down" to the show's return. People were invited to post a picture of the installation on social media (and include the hashtag #TWDFeb10) for the chance to win a lopped off zombie finger.

Taking it one step further, the agency also chained "walkers," the show's name for zombies, to the giant hands and let some free to roam the train station during peak hours.

In one week, the rotting finger installation garnered more than 18 million Twitter impressions and more than 900,000 media impressions with coverage in Toronto's biggest news outlets. The show also gained 11,000 new Facebook fans and awareness of the stunt spread across the world with mentions on more than 60 blogs in multiple countries.