I think it's the feeling of being watched. Imagine Penny on Tumblr sharing her thoughts and photos. Then she realizes that someone is closely monitoring her every post, every like, every comment. And this person has malicious intentions. Whether it's through seeing a strange face in the background of her photos or getting messages that hint at them knowing her every move, that constant feeling of being under surveillance is truly the scariest part.
For me, it would be the sense of the unknown seeping into the real world. Say Penny posts something normal like a picture of her garden. Then she starts getting comments about a dark figure that's going to come for her. And then she actually starts seeing glimpses of that figure in real life. The blurring of the line between the online Tumblr world and her real, everyday life is extremely scary.
It could be about a character named Penny who has some sort of terrifying experience on Tumblr. Maybe Sid is either a witness, a perpetrator, or another victim in this horror story. It might involve things like supernatural events, cyber - bullying on Tumblr that turns into a real - life horror, or a mystery related to Penny and Sid's online and offline lives.
There was this Penny on Tumblr. She was into exploring abandoned places and would post pictures of them. One day, she visited an old asylum. She took a photo and posted it. After that, she noticed a figure in the photo that wasn't there when she took it. The figure seemed to be getting closer in every photo she had of that place. Then, she started having nightmares about the asylum. In her dreams, she was trapped there with that figure chasing her. It got so bad that she stopped using Tumblr altogether to try and escape the horror.
For me, it's the feeling of being watched. In a graveyard, there are so many places for unseen eyes to lurk. Every rustle of the leaves, every creak of a branch could be a sign that something is observing you, and that's truly terrifying.
The scariest element could be the loss of control. Just like in the case where a person's long nails start to act on their own, moving without the person's will. It makes one feel powerless against this strange and unnatural phenomenon.
The change in their appearance. For example, if their cute yellow bodies turn into a sickly gray, and their big eyes become sunken and bloodshot. It's a huge contrast to their normal, adorable look, which makes it really terrifying.
The constantly changing shape. In a horror story, if the parallelogram keeps changing its angles and side lengths, it can create a sense of disorientation. For example, a character might think they are running in a straight line along one side, but suddenly the side shifts and they find themselves in a completely different and terrifying part of the parallelogram - like space.
The sudden contrast between the beauty of spring and the horror. For example, the bright flowers and sunshine being disrupted by a dark, menacing presence. It's like the idyllic spring setting is being corrupted.
The unknown. In Destiny, there are so many mysteries and uncharted areas. When you don't know what's lurking in the shadows or around the next corner, it's terrifying. It could be a new and powerful enemy that we've never seen before, or some strange force that defies all the rules we know about the game's universe.
The unknown source of the shedding. If you don't know what's causing it, like in a haunted house where the walls are shedding some strange substance, it creates a lot of fear because your mind starts imagining all sorts of terrifying things.
The sudden movement of the chopsticks on their own. It goes against the normal use of chopsticks and is very unexpected, like in a story where a person is calmly eating and then the chopsticks start wriggling in their hands.