Horror prank in Japan based on RINGU film is truly terrifying

I'm suprised that this horror prank, at a haunted location in Japan, didn't give anyone a heart attack. 

The prank, based on the monster from the Ring film, is truly terrifying. During the prank, someone dressed like Sadako from the Ringu film—in costume, on stilts—chases people out of a tunnel and hides near the bathroom exit as people walk around at night. This is one of the scariest costumes used in a horror prank I've ever seen. 

I wonder if the people in the video ever found out this was a prank, or if they sped home and now need therapy for the rest of their lives. 

See also: Bobs Big Boy's unintentional horror museum