Is there any more prosperous genre these days than horror? The scary, the dark, the depraved, the disturbing - both commercially and artistically, the fright flick is thriving. "Backrooms" is the latest phenomenon, after the barely 2-week-old "Obsession", but this one feels even more like an inflection point on many fronts - possible proof that something going viral can translate into a hit movie after all, that web series might be the next pool for Hollywood to drain its ideas…