Why didn't anyone told me about this masterpiece earlier? Highly recommend it

I'm not going to spoil anything but damn, such a good anime. It's horror, so it's fitting to watch it now in October, it's scary but more suspenseful and just unnerving, so if you don't like horror don't watch it. I remember seeing gifs and images years ago and being scared of it lol. It's also apparently based on a novel. High recommendation.

If anyone has watched it, what are your thoughts on it?