The bloody hand in the story is so frightening because it violates our sense of safety. We expect places to be clean and free from such gruesome signs. When we see or hear about a bloody hand, our minds start to imagine all sorts of horrible scenarios. It could be a sign of a deranged killer on the loose, or perhaps a supernatural entity. The very sight or thought of it triggers our primal fear of the unknown and the dangerous.
The bloody hand is scary because it represents violence and danger. It's a visual reminder of something bad that has happened or is about to happen. It also creates a sense of mystery, as we wonder about the story behind it. Maybe it was a victim of a brutal crime, or it could be a sign from the afterlife. All these uncertainties add to the fear factor.
The mystery around it. We don't really know who Bloody Mary is supposed to be exactly. It could be anyone from a wronged woman to a witch. And the idea that just by saying her name in a specific place (the bathroom) and in the dark, something terrifying might happen.
Well, in the bloody hand scary story, often there's a mystery around the origin of the bloody hand. It could be that a victim was trying to escape from some horror and left this mark as a last sign. Sometimes, it's related to a curse, and the appearance of the bloody hand is a warning to those who enter a particular place.
The mystery. For 'Bloody Mary', not knowing if the ritual will actually summon something is scary. In other stories too, the unknown elements are frightening. Like in a haunted house story, we don't know what's making those noises.
The mystery surrounding the hand. If the story doesn't immediately reveal where the hand came from or what its purpose is, it leaves the readers in suspense and fear. It could be a cursed object, or something from another dimension.
The darkness is a big factor. Doing the 'Bloody Mary' thing in a pitch - black bathroom makes it scarier. Also, the idea of an unknown, probably angry spirit appearing is terrifying. Just the thought of looking into the mirror and seeing something that shouldn't be there is really creepy.
The hairy hand itself is probably quite scary because it's not normal. Hairy hands usually bring to mind something wild or inhuman.
The fact that it moves on its own is really terrifying. It defies the normal state of things, and that unknown power behind its movement makes people scared.
One reason could be the unknown. If the hand in the story has some sort of strange power or origin that's not clear, it creates fear. For example, if it moves on its own and there's no explanation for it, it's really spooky.
The sight of a bloody hook is often scary because blood is associated with violence and harm. It gives an immediate sense of danger and that something bad has happened or is about to happen.
The unknown factor makes it terrifying. You don't know what's licking your hand.