You could write about haunted houses or creepy old cemeteries. They always give that spooky feel.
Another theme could be revenge. Maybe there is a wronged spirit in the 'magpakailanman horror story' that is seeking vengeance on those who did it wrong. For example, a person who was unjustly killed comes back as a ghost to haunt the people responsible for their death. This theme often adds a sense of justice, albeit a spooky and often violent one, to the horror story.
One possible theme could be the fear of the unknown. Since it's a horror story, Abigail and Sanam might be facing something they can't understand, like a strange supernatural force. Another theme could be isolation. If they are in a situation where they are cut off from help, it adds to the horror. For example, if they are in a desolate place like an old, empty building in the middle of nowhere.
One possible theme could be isolation. The Rohtang Pass is a remote place, and being alone or cut off from help in such a location can be very scary.
The theme of lost dreams could also be present. Many people come to Los Angeles with big dreams that often don't come true. In a horror context, these unfulfilled hopes could turn into something menacing. Maybe the ghosts of those who failed are out to haunt the new arrivals, or there are supernatural forces that prey on the desperation of those chasing their dreams in LA.
One possible theme could be the fear of the unknown. Since the knock is something mysterious, it represents the unknown danger lurking.
In 'gorgon a horror story', a likely theme is the battle between good and evil. The Gorgon could be seen as an embodiment of evil, and the characters who oppose it represent good. Another theme could be the theme of transformation, not just in the literal sense of being turned to stone, but also in how the characters are changed by their encounters with the Gorgon. They might become more cautious, more desperate, or even more heroic in their attempts to survive.
The theme of the unknown can also be present. There could be strange, unidentifiable shapes or noises in the dream. The dreamer doesn't know what these things are or what they might do, and this uncertainty creates a sense of dread.
A theme of betrayal could also be present in the Veronica horror story. Perhaps someone she trusted, a friend or a family member, has led her into the horror situation. Or there could be a betrayal from a supernatural entity that she thought she could trust or make a deal with. This betrayal then becomes a major part of the horror that she has to endure.
Another theme might be the idea of a cursed object. The ribbon could be cursed, and anyone who interacts with it is doomed to face horror. This theme often plays on the fear of the inescapable consequences of coming into contact with something that is 'tainted'. For example, the characters in the story might try to get rid of the ribbon, but it always finds its way back to them, bringing more and more horror. It could also be about the theme of revenge. Maybe the ribbon was once a symbol of love or friendship, but something bad happened, and now it's a tool for revenge, and the horror it brings is the revenge being exacted on the unwitting victims.
One possible theme could be the fear of the unknown. When we don't know what's out there in the dark or in an unfamiliar place, it can be truly terrifying.