It Follows (2015)

Perhaps one of the most unsettling horror films of this decade, David Robert Mitchell's sophomore entry It Follows left quite the mark upon its release. Widely regarded among film lovers as one of the best horror movies of the decade, it still didn't achieve the mainstream success that studio franchises such as James Wan's Insidious and The Conjuring series managed during the decade. There's a great monster at the center of this film that keeps the tension ramped up from start to finish.