One possible element is a haunted location. The princess might live in a spooky castle filled with secret passages and rooms where strange things happen. Another element could be a malevolent force like a demon or a powerful sorcerer who targets the princess. For example, the sorcerer might use dark magic to make the princess see terrifying visions.
There could be a tragic backstory. Maybe the princess was born on an unlucky day, and it was prophesied that she would bring doom. This led to her being shunned by some in the kingdom. Then, as she grew up, those negative emotions attracted dark entities. Also, a death - related element can be there. For instance, the princess might be haunted by the ghosts of those who died unjustly in the castle long ago.
Ghosts could be a possible element. In 1928, superstition was still quite prevalent, and a horror story might involve the apparition of a vengeful spirit.
Well, in Sleeping Beauty, Maleficent could have been even more terrifying. What if when she cursed Aurora, she also made it so that all the animals in the forest turned against Aurora. So, instead of cute little friends, they were out to get her, with sharp teeth and menacing growls. It would make the story much scarier.
One common element is a curse. Often, a princess is cursed by an evil witch or sorcerer. Another is a spooky setting like an old castle or a dark forest. For example, in many stories, the princess is trapped in a haunted place.
One possible element could be a creepy old mansion. It might be abandoned and full of dark corners where strange things happen.
The waiter himself could be a key element. He might have a past he doesn't remember, which is somehow related to the horror. For example, he could have been involved in a murder at the restaurant in a past life, and now the spirits are coming back to haunt him. Also, the customers could be strange, like they are not really human but some sort of otherworldly beings just pretending to be normal diners.
One possible element is the sudden and terrifying hallucinations. People on bad 'ecstasy' might see grotesque monsters or distorted versions of people around them.
Malfunction could be one. Like when it doesn't stop vibrating or changes its pattern unexpectedly.
The Detroit Horror Story may contain elements such as the isolation of certain neighborhoods. These areas, cut off from the rest of the city, can feel like a world of their own, full of mystery and danger. The presence of graffiti - covered walls and broken streetlights can add to the spooky atmosphere. There could also be elements related to the city's history of racial tensions, which could manifest in stories of hauntings or vengeful spirits.
One possible element could be the use of his unique musical sounds as a trigger for the horror. His music often has intense and somewhat otherworldly beats that could be associated with something sinister.