As children, Marina and her friend Rebecca stabbed their friend Lily as an offering to “Mercy Black,” a mysterious creature that promises to take away their and their families’ pain. 15 years later, Marina has returned home from the psychiatric hospital, and so, it appears, has Mercy.

This is pretty clearly inspired by the 2014 Slender Man case, and (from what I’ve heard, as I haven’t suffered through it personally …) better than the “Slender Man” movie. There are some interesting ideas about belief explored, and about the spread of urban myths, and there’s good atmosphere, tension, and scares. The ending is a little loose, with a couple of surprising twists, and it ends on a much more nihilistic note than I expected.

I didn’t go into this movie with very high expectations – it’s a Blumhouse straight-to-streaming release – but I came away enjoying it quite a bit more than I expected to. Maybe not destined to be a classic, but definitely a fun rainy-day movie.