Imagine minding your own business, waiting for an elevator to open up, when the doors pull back to reveal a strange man choking a victim. What would you do? Scream? Run? Call 911?

All of those reactions are very natural, judging by what happened when viral marketing agency Thinkmodo concocted its phony elevator murder scene. It was all in service of promoting the new Colin Farrell film, Dead Man Down, to capture people's reactions via video. One after another, people walked up to the elevator — coaxed there by a Craigslist ad asking for research participants — and then got the shock of their lives. The agency is extremely lucky no one got hurt, though one person did smack down the fictional assailant with a bouquet of flowers.

The incident is reminiscent of last year's ghost elevator prank from Brazil. (I don't know about you, but I kept watching this, wondering when one of these people would start clutching their chest.)

No lie, this is trés creepy. Ghost children might be the freakiest phantasms ever.

Viral video is like the holy grail of modern marketers and entertainment programs these days, and for as long as that continues, you know this type of shock content will go on… that is, until one of the "punkees" reacts with a knife or a gun. Might be time to think about that, Thinkmodo.