Photo booths: where couples smooch and friends get goofy for the camera.
But these poor prank victims might now think of photo booths as dark, enclosed boxes where murder awaits. Cue the daunting music.
Black Box TV positioned two horrifying figures with makeshift weapons and masks on either side of a photo booth, waiting until the smiling occupants settled in for their snapshot and then whipping back the curtain and hollering murderously.
The result is a strip of photos showing the subjects screaming. The video has more than 247,000 views on YouTube.
If the video was intended to be anything but terrifying, the humour is dampened by no one appearing to laugh or even smile when they're told it's a prank. Some of the victims get angry, swear and the last one even cries.
Black Box TV's last prank elicited similar angry reactions from job seekers brought into a warehouse and then frightened with a chainsaw. In another prank from May, people touring an apartment see a woman lying on the floor covered in blood. A man runs out wielding a weapon and chases them in a scene that could give even the toughest of horror film-lovers a heart attack.
YouTube users regularly call the pranks staged, but if they are real, let's hope these victims appreciate a good scare.