Satanic
“Four friends on their way to Coachella stop off in Los Angeles to tour true-crime occult sites, only to encounter a mysterious young runaway who puts them on a terrifying path to ultimate horror.”
That was the synopsis I found on IMDB… Here is my version:
“Four friends encounter a girl who makes a grafiti on their hotel wall before slashing her own throat. By doing so, she calls the Devil, who manifests himself by killing birds in a pool, sticking cuttlery on the kitchen ceiling and making very heavy footsep sounds.”
If that’s what people call “the ultimate horror”, then I’m Gandalf because there is even more horror in The Lord of the Rings.