Starting today, fans can check out 20th Century Fox's new thriller Devil's Due in theaters, but earlier this week, several unsuspecting New Yorkers got the scare of a lifetime, thanks to an elaborate prank set up by the ad firm ThinkModo. The video, which currently has over 30 million views on YouTube, showed an unattended baby in the streets of New York City. When onlookers came to get a closer look at the infant, they got the shock of a lifetime, as this animatronic demon baby sprang to life, spewing projectile vomit and even giving "the bird" to some NYPD cops. Today, we have a behind-the-scenes video which showed some of the early tests of this baby's creation. Take a look at the video, then read on for more facts about this prank.

The campaign reportedly cost between $500,000 to $1 million, but this video has already amassed more hits than six of YouTube's most watched videos from 2013, so the cost was well worth it. The baby itself and the remote-controlled stroller took more than 200 hours to construct over the course of four weeks. The robot baby has 11 servo motors, with skin made of silicone and goat hair which was individually punctured into the "skin." The stroller motors were actually taken from two DeWalt drills, with a maximum speed of 2 miles per hour. The baby and stroller were controlled via model airplane remote controls, while the baby's evil sounds came from an iPod that was connected to a transmitter and speakers hidden within the stroller.

However, not everything went according to plan. During one take, the projectile vomit traveled so far that it actually hit one of the cameramen, and the drive belt on the stroller broke after it went over a pothole. Plus, the video was shot during the cold snap now known as the "Polar Vortex," which caused the motor controlling the eyes to freeze up. The baby couldn't blink until they thawed the motor out with a hair dryer.

CLICK HERE to check out the original video before heading to the theaters to see Devil's Due.