“Come children, gather round, but remain silent, for the sun has fallen. Shhhh….,” says the wizened old woman. Outside, a gentle breeze calmly rustles the trees and the moon lights the sky. The danger moves freely though.
In the above there’s no actual threat, rather there is the mention of the threat. Something could happen. Consequences are presented, but the monster could be just about anything. Truthfully, that’s what a monster is. The specifics don’t matter in this instance, but as the story progresses the monster would be revealed.
The monster would be entirely dependent on the context created by the story. It helps to have a connection between the story, the threat, and the threat’s manifestation. It doesn’t need to be a bland monster. If people are being drained of their blood, most people would think vampire, but it could be something else. Maybe it’s a pack of stirges, some kind of blood-drinking slime infestation, or really anything. Whatever it is, it should match the threat. Choosing a monster is like choosing a tool. You need to have the right one for the job. If you choose the wrong one, you might get the job done, but it might not be quality work.
At the end of the day, there is no one monster to rule them all. I love all my dreadful creatures, and even the loveable squishy ones. Every monster has its role to play. I love them all.