I LOVE this teaser.
It’s genuinely more creepy than some entire movies (which shouldn’t be a surprise considering the movie–and I assume this teaser–was directed by Mike Flanagan (Oculus, Hush, Ouija: Origin of Evil) because it’s all about projecting a haunting, vaguely sinister atmosphere.
Proof that what you don’t see can be as scary as what you do because there are plenty hints of some horrific events, but nothing is revealed.
Sometimes less is indeed more.