The Austrian horror film GOODNIGHT MOMMY seems to have come out of nowhere. I was first introduced to it at a secret screening during 2014’s Fantastic Fest in Austin, Texas. I had no clue what I was in store for. Not only was the screening unannounced, I had never even heard of the film or the filmmakers before. Now it is playing this year’s Boston Underground Film Festival, though the premise of the film is still a bit shrouded in mystery to American audiences. Most films benefit from the viewer being slightly in the dark about what they are about to see, and GOODNIGHT MOMMY embeds this proclivity to mystery by telling the story through children.