In 1998, there was a famous case in East Java, Indonesia, which involved a scary mythology figure known as "penanggalan," which is a female creature with a head that detaches from her body, and flies around at night searching for victims to suck their blood.
People in East Java became very afraid of this creature and rumors started to spread that some people were transformed into the "penanggalan." People also claimed to see bloodstains and other marks that supported these rumors.
So, many people started to take precautions to protect themselves, such as placing thorns or sharp objects around their houses, using amulets or potions, and even sleeping with the lights on.
The situation became so severe that the Indonesian Government intervened and created a team to investigate these claims. The team found no evidence of any supernatural or mythical creature, and instead, they discovered that the source of the rumors was due to mass hysteria and panic.
The team concluded that the social and economic instability in East Java after the Asian financial crisis created a sense of fear and anxiety among the people, leading to the emergence of this urban legend.
In simpler terms, people in East Java were scared of a scary story about a creature that wasn't real. This fear was due to a difficult time in their lives, and their minds created this story, making people believe it was true.