These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Nightmare Fuel - Most cases with a supposedly "supernatural" culprit count. There are many of them. The live action "The Seven Mysteries of the School" ("Smoke and Mirrors" in the U.S. manga translation) case had a scene involving a science lab at night with a jar containing a human head that suddenly...opened its eyes.