In case you haven't heard of it, Goodnight Mommy is a new psychological horror film from director Matt Sobel (Brand New Cherry Flavor).
And it's actually an English-language adaptation of the 2014 Austrian film of the same name, which is also known as Ich seh, Ich seh in German.
For a little backstory, the 2014 version was quite popular, scoring an 85% on Rotten Tomatoes with critics. And it even gained something of a cult following over the last few years.