Prompts that start a story
A useful prompt gives you more than an atmosphere. It gives a person, a place, something wrong and a reason the person can't simply leave. Each prompt here is assembled from hand-written pieces built to fit together: the character suits the setting, the disturbance suits the sub-genre, and the complication raises the stakes.
Intensity changes the kind of complication you get, from a slow, deniable strangeness to an immediate threat. If you want something specific, lock the options you care about and let the rest vary.