Workers at a Costa Rican hospital were mystified when the siren of an ambulance activated on its own and a later check of the security footage from the site revealed an eerie shadow moving away from the vehicle. According to a local media report, the strange incident occurred last Friday evening at a Red Cross facility in the district of Pocosol. As seen in the video below, staff at the site that night were startled by an ambulance's siren that inexplicably came to life. Rushing out to the parking lot to deal with the situation, the puzzled workers found no one in the area who could have been behind the sudden commotion.

Curious to get to the bottom of the odd event, staff subsequently turned to the building's security system and saw that, seconds after the siren turned on, a peculiar shadow was captured leaving the scene as the workers exited the building. Since being posted online, the spooky video has gone viral on social media in Costa Rica with many viewers suggesting that the curious form seen in the footage could have been a mischievous ghost that wanted to give the workers a scare. Meanwhile, more skeptical observers have argued that the incident was probably a prank pulled off by a particularly furtive troublemaker. With that in mind, what do you mean of the weird scene? Weigh in with your thoughts at the C2C Facebook page.